wales bowel cancer screening pilot ......letter plus the full kit enhancement pack (containing...

Published August 2016

WALES BOWEL CANCER SCREENING PILOT: EVALUATION REPORT

PROJECT DATES: FEBRUARY TO APRIL 2015

2

ACKNOWLEDGEMENTS This pilot was developed in partnership with Public Health Wales, and funded and project managed

by Cancer Research UK (CRUK). Public Health Wales Screening Division (PHW) shared insight,

supported with stakeholder engagement and conducted analysis of the uptake data, with support

from Cancer Research UK.

The mailed interventions were fulfilled and distributed by DST Output UK, the mailing house

contracted to manage the bowel cancer screening invitation process for Public Health Wales.

This report was compiled by Becky White, Rosie Hinchcliffe, Helen Clayton, Nick Ormiston-Smith,

Kathryn Weir, and Hayley Heard.

3

CONTENTS

SUMMARY .............................................................................................................................................. 4

BACKGROUND ........................................................................................................................................ 5

EVALUATION METHODS ......................................................................................................................... 7

RESULTS ................................................................................................................................................ 15

DISCUSSION .......................................................................................................................................... 16

CONCLUSIONS ...................................................................................................................................... 18

END NOTES ........................................................................................................................................... 19

APPENDICES .......................................................................................................................................... 20

4

SUMMARY

Cancer Research UK (CRUK) worked in partnership with Public Health Wales Screening Division

(PHW) to run a Bowel Cancer Screening (BCS) service improvement pilot across Wales, from

February to April 2015. This project built upon learning gained from an earlier BCS pilot, which ran in

London in 2014. It aimed to encourage men and women aged 60-74 to complete and return their

guaiac Faecal Occult Blood Test (gFOBT) kit when it is received, by reducing barriers to completion.

The primary outcome measure was change in gFOBT uptake at 12 weeks after invite (i.e. the date

the invitee is sent the NHS test kit). Analysis showed that a personalised CRUK endorsement letter

(intervention A) sent three days following the NHS test kiti increased uptake amongst all screening

history groups, with the largest impact in those being invited for the first time (9.1% absolute

increase). The CRUK endorsement letter plus a kit enhancement pack containing three pairs of

gloves (intervention B) also increased uptake in “first-timers”ii (5.5% increase) and “previous non-

responders” (2.3% increase), yet it had the greatest impact in more deprived non-responders (3.2%

increase), particularly more deprived male non-responders (3.9% increase). The CRUK endorsement

letter plus the full kit enhancement pack (containing gloves & poo catcher) (intervention C)

increased uptake amongst non-responders (2.4% increase) only.

Out of home advertising (posters, pharmacy bags, press articles etc.) on its own (intervention D) did

not increase uptake in any of the screening history groups, and uptake among ‘previously screened’

invitees was significantly lower than controls. However, secondary qualitative research

commissioned to further understand these results did not identify any elements of the advertising

that discouraged participation, suggesting that the observed decrease in uptake could be caused by

factors that could not be accounted for in the uptake analysis. Nevertheless, some potential

improvements to the posters were highlighted by focus group participants.

In conclusion, the CRUK endorsement letter (A) worked effectively across the full screening

population, potentially because it was personalised (making it highly relevant to the individual), and

functioned as an additional cue to prompt participation, since it was received following an NHS test

kit. Results also suggest that a targeted approach would be more beneficial in helping to reduce

inequalities in Wales, by sending the CRUK endorsement letter (A) to first-timers only, and the CRUK

endorsement letter plus gloves (B) to non-responders in more deprived groups.

i The CRUK endorsement letter was designed to arrive approximately 2-3 days following the NHS test kit ii First-timers were defined as those being invited to screening for the first time, previous non-responders were

those who had been invited before but had never returned a used test kit, and previously screened were those

who had been invited before and returned a used test kit.

5

BACKGROUND Bowel screening in Wales

Bowel cancer is the fourth most common cancer in Wales and more than 900 people die from it each

year.1 Bowel screening aims to detect bowel cancer at an early stage when treatment is more likely

to be effective. In Wales, a bowel screening guaiac-based Faecal Occult Blood Test (gFOBT) kit is sent

via post every two years to men and women aged 60-74. Unfortunately uptake of the test in Wales

remains lower than target at around 51%.2

However, it is estimated that the NHS Bowel Cancer Screening programme will cut deaths from the

disease by 25 per cent among those who complete the test at least once3. By 2025 it is predicted

that gFOBT will save over 2,000 lives from bowel cancer each year in the UK4. In Wales, a number of

psychosocial barriers to participation have been identified, including:

• Fear and denial around the test outcome (i.e. preferring not to participate for fear it will be

a positive result)5-8

• Belief that it isn’t necessary to complete the test if you don’t have any symptoms 6, 8-10

• Belief that the test is difficult, unpleasant or unhygienic 7-11

• Poor knowledge of benefits and eligibility 6-12

Various interventions have been shown to increase uptake of gFOBT bowel screening.13 Cancer

Research UK (CRUK) and Public Health Wales (PHW) Bowel Screening Programme worked in

partnership to pilot four such interventions in Wales.

Project aims

The primary aim of the project was to increase participation in gFOBT by raising awareness of the

NHS bowel cancer screening programme (i.e. benefits/eligibility) amongst the eligible population,

and reducing barriers to participation:

• Increase uptake of gFOBT by 2 - 6%iii

• Raise awareness of the effectiveness of the test , along with benefits (and risks) of the

test

• Reduce beliefs that the test is difficult to complete

Interventions

An initial pilot project implemented in Greater London (2014) found that a CRUK endorsement flyer

(A5) included within an NHS test kit mailing failed to have an impact on gFOBT bowel screening

uptake. However, when the flyer was combined with either a separate kit enhancement pack

mailing, containing gloves and poo catchers (arriving approximately 2 days after the NHS test kit), or

with advertising, there were small but significant increases in uptake. When the CRUK flyer, kit

enhancement pack, and advertising were all combined together, uptake increased by 6.1 percentage

points among 60-69 year olds, and 7.3 percentage points among 70-74 year olds14.

iii The estimated increase in uptake was based on evidence from the London pilot. Uptake was expected to vary depending on screening

history, age, gender and level of deprivation

6

The pilot in Wales aimed to build on these learnings by re-formatting the flyer into a personalised

endorsement letter and sending it separately from the NHS test kit (posted 3 days followingiv), with a

view to understanding whether an additional contact had more impact. The individual impact of the

most effective intervention in London (i.e. flyer, kit enhancement pack (gloves & poo catcher) and

advertising) was explored further in Wales by posting three different versions of direct mail (see

below) and running advertising alone. The contents of the kit enhancement packs (pack) were also

split out to establish the relative cost effectiveness of each. The interventions were:

• Intervention A: CRUK endorsement letter

A4 personalised CRUK endorsement letter, outlining the benefits (and risks) of participating

in the NHS bowel cancer screening programme and providing a recommendation from CRUK

to complete the test. Posted three days following an NHS test kit with the aim of it arriving

2-3 days following an NHS test kit.

• Intervention B: CRUK endorsement letter plus pack with gloves

CRUK endorsement letter plus x1 kit enhancement pack containing x3 pairs of latex free

gloves. Posted three days following an NHS test kit with the aim of it arriving 2-3 days

following an NHS test kit.

• Intervention C: CRUK endorsement letter plus pack with gloves & poo-catchers

CRUK endorsement letter plus x3 kit enhancement packs; each containing x1 pair of gloves

and x1 poo catcher. Posted three days following an NHS test kit with the aim of it arriving 2-

3 days following an NHS test kit.

• Intervention D: Advertising only

Advertising only; consisting of posters on bus stops, posters on phone boxes, posters on the

interior, exterior and backs of buses, posters in pubs and shopping malls, on pharmacy bags

and press articles in regional press titles.

See Appendix 1 for examples of the intervention materials. For intervention costs, see Table 1

(summary) & Appendix 2 (detailed).

TABLE 1: SUMMARY OF INTERVENTION COSTS

Intervention A Intervention B Intervention C Intervention D

Total sample that

received intervention

9,300 7,300 7,300 11,094

Total sample included

in final analysis

8,875 6,995 6,981 11,094i

Total cost: £7,380.32 £12,417.87 £19,516.78 £69,126.91

Inclusions: Set up fees,

print

production,

fulfilment,

envelopes,

Welsh

translations for

letters and

mailing costs

As per

intervention A,

plus purchase and

delivery of kit

enhancement

packs containing

gloves only

As per

intervention A,

plus purchase and

delivery of kit

enhancement

packs containing

gloves & poo

catchers

Design and

artwork fees,

print production

and paid media

costs

i Sample receiving intervention D was defined at the analysis stage as those people identified as

having been exposed to advertising.

iv The CRUK endorsement letters were designed to arrive approximately 2 days following the arrival of NHS kits, as NHS kits were sent on a

Friday, and the CRUK letters were sent 3 days later on the following Monday. NHS kits would take an extra day to arrive due to the postal

service not running on a Sunday, so were likely to arrive Monday or Tuesday, whilst the CRUK letters were likely to arrive the following

Wednesday or Thursday.

7

EVALUATION METHODS Objectives

The final primary outcome measure was uptake at 12 weeks after invitation, amongst those aged 60-

74 who were eligible for the programme. An earlier initial analysis, also referenced in this document,

measured uptake at 6 weeks after invitation. The analysis of PHW bowel cancer screening uptake

data aimed to:

1. Determine whether the interventions significantly increased gFOBT uptake at 6 and 12

weeks after the invitation date, with all other factors (for which there is data) taken into

account.

2. Identify which intervention groups had the largest increases in uptake compared to

controls, in order to better identify the most effective interventions.

3. Identify demographic groups where the interventions had the greatest impact.

Secondary evaluation measures were used to further understand the results. After the uptake

analysis, follow-up qualitative research (focus groups) was commissioned to understand the

observed impact of advertising on uptake in previously screened invitees, and to identify any

improvements that could be made to the advertising. The methods and brief findings are detailed

in appendix 12, with insights incorporated into the discussion.

Summary of uptake analysis

The uptake analysis aimed to identify the impact of the interventions on uptake, by comparing

uptake amongst invitees in each intervention group to controls, who received normal care.

Logistic regression models were used to predict the probability of screening uptake in each

intervention group (A, B, C or D) compared to records in the control group. The models controlled

for other demographic variables that were found to affect uptake (deprivation, gender, age, and an

ethnicity proxy). Data for some factors known to be associated with bowel screening uptake such as

invitee’s ethnicity and household size were not available, however an area-based (Lower Super

Output Areas) proxy for ethnicity was available for the 12 week analysis.

The main effects of each intervention on the probability of screening uptake were modelled

separately for the three screening history groups; “previously screened”, “first-timers” (those being

invited for the first time) and “non-responders” (those who have been invited before but have not

returned a kit). This was due to large differences in underlying uptake as well as differing

intervention effects between the three groups.

For each of the three stratified models, further subgroup analyses were conducted to compare the

impact in the interventions in more deprived (Welsh Index of Multiple Deprivation (WIMD) quintiles

4 & 5) and less deprived (quintiles 1,2 & 3) invitees, and specifically amongst more deprived

(quintiles 4 & 5) males.

8

Intervention & control group allocation

Table 2 gives an overview of the interventions and the dates and areas where they were

implemented. Due to the complexity of the campaign, interventions were not randomly allocated on

an individual basis, but were allocated by week (see Appendix 3 for a breakdown of the intervention

group allocations by week). This approach was suitable for this project because the majority of

variation in uptake over time is driven by factors such as screening history and age of the

respondent, which could be accounted for at the analysis stage.

Posted interventions (A, B and C) were allocated by the week that the recipients were invited. All

people invited in the first week of the intervention received that intervention. NHS test kits are sent

out once a week, on Fridays. The posted interventions in this pilot were then sent out the following

Monday. Where the numbers invited in the first week were lower than the target sample size for the

intervention (7,300), invitees from a second “overspill” week were also sent the posted intervention.

The target sample size for each intervention was 7,300. This was larger than the minimum 4,356

cases needed to detect an increase in uptake of at least 3% (see Appendix 4 for power calculations),

as we anticipated that up to 40% of cases may need to be excluded at the analysis stage due to

contamination by advertising (see page 9 for more information on contamination). However, it was

possible at the results stage to account for contamination in the model, and a sensitivity analysis

also showed that contamination did not have a major impact on results, so the full sample of up to

7,300 cases were included in the results.

The majority of advertising activity ran in Cardiff & Vale and Aneurin Bevan Health Boards from 16th

March to 12th April 2015, with some bus activity (i.e. posters on buses) continuing for a further two

weeks until 26th April. Some of the advertising (i.e. bus activity) also spilled over into the

neighbouring Health Board of Cwm Taf. Intervention D was defined as those people sent kits from

Friday 20th March to Friday 17th April 2015 (inclusive) in Aneurin Bevan and Cardiff & Vale Health

Boards.

There was an error on the endorsement letters sent in the first week of intervention A (intervention

posted 30/01/15), where addressees’ first names and last names were in the incorrect order.

Intervention A was therefore rerun after the advertising had finished (intervention posted

20/04/15), to ensure an adequate sample of invitees sent the correctly addressed endorsement

letters. During the rerun week, the intervention was not sent to those invited in areas that had just

received advertising, i.e. Aneurin Bevan, Cardiff & Vale, and the advertising overspill area Cwm Taf.

Uptake in each of the intervention groups (A, B, C or D) was compared to uptake in a control group.

Invitees were identified as controls if they were sent gFOBT kits between Friday 16th January 2015

and Friday 29th May 2015 and received “normal care” (i.e. they did not receive any of the posted

interventions (A, B, or C) and were not identified as having been invited in an advertising area during

the advertising campaign (intervention D)).

9

TABLE 2: INTERVENTION & CONTROL GROUP ALLOCATIONS

Intervention group

Weekly kit sent

dates included1

Dates intervention

mailed/ advertising

ran

Location Total

sample2

Intervention A

CRUK endorsement letter

Fri 30th Jan 15

Fri 6th Feb 15

Fri 17th April 15

Mon 2nd Feb 15

Mon 9th Feb 15

Mon 20th April 15

Pan Wales3 8,875

Intervention B

CRUK endorsement letter + pack

(gloves only)

Fri 13th Feb 15

Fri 20th Feb 15

Mon 16th Feb 15

Mon 23rd Feb 15

Pan Wales 6,995

Intervention C

CRUK endorsement letter + pack

(gloves & poo-catcher)

Fri 27th Feb 15

Fri 6th March 15

Mon 2nd Mar 15

Mon 9th Mar 15

Pan Wales 6,981

Intervention D

Advertising only

Fri 20th March

Fri 27th March

Fri 3rd April

Fri 10th April

Fri 17th April

Advertising ran from

Mon 16th Mar 15 to

Mon 26th Apr 15

2 Health

Boards in SE

Wales:

Aneurin Bevan

& Cardiff and

Vale

11,094

Controls: All other people sent

invites from during study period,

who received normal care (i.e. did

not receive any of the mailed

interventions and were not

invited in one of the areas that

received advertising during the

campaign period)

Selected invitees

from

Fri 16th Jan to

Fri 29th May

N/A Pan Wales 67,761

1 Kits are sent each Friday. The call run file (i.e. details of those to be sent a kit) is generated the Friday before. 2 Total sample included in analysis, after exclusions. Includes contaminated cases. 3 Rerun week for intervention A (kits sent 17th April) did not include those sent kits in Aneurin Bevan, Cardiff &

Vale, and Cwm Taf.

Definition of uptake

An invitee has been counted as screened if they return a used test kit within 6 weeks (initial results)

or 12 weeks (final results) after the date they are originally sent their kit. This measure (returned a

used test kit) is consistent with PHW’s definition of uptake, but is different to the definition used in

the London Bowel Cancer Screening Campaign improvement pilot. In the London pilot an invitee had

to have returned a valid test kit, or have reached a definitive test result of either normal or

abnormal, in order to be counted as adequately screened.

Further analysis of the London pilot results showed no significant differences in the impact of the

interventions if the definition of uptake was similarly widened to include anyone who sent back a

test kit, due to the relatively small numbers of people who returned spoilt kits in London.

Eligibility and exclusions

In Wales, bowel cancer screening kits are routinely sent every two years to eligible men and women

aged between 60-74 years, beginning at their 60th birthday. Whilst the process to identify invitees is

10

the same in England and Wales, it should be noted that there are differences in the subsequent

process to identify the eligible population for the purposes of uptake analyses.

For this particular analysis, PHW excluded individuals who would not have been able to receive the

interventions, such as prisoners, and those who would have been sent a FIT (Faecal

Immunochemical Test) kit in this particular round, due to an inconclusive result in their last

screening round. These numbers are negligible (only 53 people).

In the 12 week analysis, a further 1,055 people were excluded because they met other ineligibility

criteria at the analysis stage. 3,761 were then excluded because they could not be linked to a WIMD

score. Unfortunately, 14 people were erroneously included in the analysis despite missing Health

Board of residence.

Variables included in dataset

The following variables were included in the dataset; the invitee’s age group, gender, screening

history, deprivation quintile (Welsh Index of Multiple Deprivation (WIMD)), Health Board of

residence, the week they were sent their kit, their allocated intervention group, whether they may

have been contaminated by the advertising campaign (i.e. seen the advertising when it was not

intended), whether they were eligible, and whether they returned a used test kit within 12 weeks

after they were sent their kit, or within 6 weeks for the initial analysis (see Appendix 5 for

metadata). Not all variables were included in the final logistic regression models.

In the final 12 week analysis, we also included an area level estimate of the individual’s likely

ethnicity, sourced from the ONS 2011 census. It is a proxy estimate, based on the percentage of

residents in the individual’s Lower Super Output Area (LSOA) that are white versus non-white.

Univariate analysis

Univariate analysis identified variables that impacted uptake, including other variables that we

would need to account for when modelling the effect of the intervention group. The univariate

analysis was conducted at the 6 week analysis, and not repeated at 12 weeks, except for ethnicity,

which was added to the model at 12 weeks. See Appendix 6 for univariate results.

Multivariate analysis development

A multivariate logistic regression model was developed to account for confounding factors that were

known to affect uptake (where data was available). Beginning with the intervention variable, other

explanatory variables were added to the main model; age group, screening history, deprivation

(WIMD quintile), gender, and ethnicity quintile. These variables were included in the final multivariate

model because they were significant predictors of uptake after controlling for the other predictors (p

<0.05), and were not closely interrelated with other explanatory variables.

The invitee’s Health Board of residence was not included in the final multivariate analysis, as this

would have introduced collinearity with the intervention variable. This is because intervention D was

mostly defined by the invitee’s Health Board of residence, as the advertising campaign ran in only two

Health Boards (Cardiff & Vale and Aneurin Bevan).

Week of invitation was not included in the final multivariate analysis. Further descriptive analysis

showed that a large proportion of variation in uptake by week could be explained by the proportion

11

of invitees each week who had been screened before (as uptake is substantially higher amongst

previously screened people than previously unscreened people). As interventions were defined by

week, introducing week of invitation as another variable could also have introduced collinearity.

Models split by screening history

Model development showed that when screening history was added to the model, there were notable

changes in the effect of the intervention groups on uptake. Whilst the univariate model for

intervention group showed that uptake was higher in intervention groups A, B and D compared to

controls, the model with both intervention group and screening history showed no significant

differences in uptake between intervention groups and controls, with the exception of A (see Table 3,

row: “Version 1) All invitees, contamination not accounted for”, column: “B) “Multivariate model”).

Screening history is likely to be the dominant driver of variation in bowel screening uptake, and the

proportion of people invited who have been screened before varies greatly week by week. This would

mask the comparatively smaller effects of the interventions, which were allocated on a weekly basis.

The decision was therefore made to stratify the main multivariate logistic regression model, and

report on the main effects of the interventions in different screening history groups; previously

screened invitees, first-timers, and non-responders. Table 3 shows a sensitivity analysis of the results

for the interventions at 6 and 12 weeks, using these different approaches to modelling screening

history (see row: “Version 1) All invitees, contamination not accounted for”, columns: di, dii, diii).

Stratification also enabled us to model interactions between screening history and other

demographic variables that affect uptake, without the added complexity of introducing interaction

variables into the models. For example, there was a different relationship between age and uptake

in previously screened invitees, compared to “first-timers”, and “non-responders”.

There was also an interaction between gender and deprivation occurring in previously screened

invitees only. This was omitted from the final model results for consistency between the three

stratified models.

12

TABLE 3: SENSITIVITY ANALYSIS OF INTERVENTION GROUP RESULTS, BY APPROACH TO SCREENING

HISTORY AND CONTAMINATION

Rows show results from model versions using different approaches to contamination. Columns show results from univariate & multivariate models: a)

without accounting for screening history, b) accounting for screening history, c) accounting for screening history and all other significant predictor variables

in the main model, and d) stratifying the main model by screening history. Results are shown both for initial 6 week and 12 week uptake analyses.

Intervention

group

a) Univariate model

(intervention group

only)

b) Multivariate model

(intervention group +

screening history)

c) Main model


screening history + all

other predictor

variables*)

di) Stratified model:

Previously screened

dii) Stratified model:

First-timers

diii) Stratified model:

Non-responders

6 Weeks 12 Weeks 6 Weeks 12 Weeks 6 Weeks 12 Weeks 6 Weeks 12 Weeks 6 Weeks 12 Weeks 6 Weeks 12 Weeks

Version 1) All invitees, contamination not accounted for

Intervention A 1.36* 1.39* 1.19* 1.24* 1.19* 1.23* 1.05 1.09* 1.49* 1.46* 1.47* 1.43*

Intervention B 1.43* 1.48* 1.04 1.06 1.03 1.05 0.94 0.95 1.27* 1.26* 1.45* 1.38*

Intervention C 0.99 0.98 1.05 1.04 1.05 1.04 0.96 0.94 1.18* 1.14 1.37* 1.39*

Intervention D 1.08* 1.10* 0.97 0.99 0.96 0.99 0.91* 0.92* 1.04 1.09 1.05 1.11

Version 2) Completely excluding contaminated invitees

Intervention A 1.36* 1.42* 1.20* 1.28* 1.21* 1.27* 1.11* 1.18* 1.44* 1.45* 1.41* 1.40*

Intervention B 1.42* 1.46* 1.06 1.09* 1.05 1.08 0.97 1.00 1.15 1.15 1.54* 1.50*

Intervention C 0.98 0.97 1.04 1.03 1.04 1.03 0.97 0.93 1.09 1.08 1.41* 1.45*

Intervention D 1.07* 1.08* 0.98 1.00 0.97 1.01 0.94* 0.95 1.04 1.09 1.04 1.09

13

Intervention

group

a) Univariate model

(intervention group

only)

b) Multivariate model


screening history)

c) Main model


screening history + all

other predictor

variables*)

di) Stratified model:

Previously screened

dii) Stratified model:

First-timers

diii) Stratified model:

Non-responders

6 Weeks 12 Weeks 6 Weeks 12 Weeks 6 Weeks 12 Weeks 6 Weeks 12 Weeks 6 Weeks 12 Weeks 6 Weeks 12 Weeks

Version 3) All invitees, with contaminated invitees moved to a separate “contaminated” intervention group within the intervention group variable

Intervention A 1.36* 1.42* 1.20* 1.28* 1.20* 1.27* 1.11* 1.18* 1.44* 1.45* 1.40* 1.39*

Intervention B 1.42* 1.46* 1.05 1.08 1.04 1.07 0.97 0.99 1.14 1.14 1.55* 1.50*

Intervention C 0.98 0.97 1.04 1.03 1.04 1.03 0.97 0.92 1.08 1.08 1.43* 1.46*

Intervention D 1.07* 1.08* 0.98 1.00 0.98 1.01 0.94 0.95 1.04 1.10 1.05 1.10

Contaminated

intervention

group

1.03* 1.01 1.07* 1.05* 1.08* 1.08* 1.09* 1.08* 1.09* 1.09* 1.09 1.07

Version 4) All invitees, with contaminated invitees included in original intervention groupings, plus a separate contamination variable

Intervention A 1.36* 1.39* 1.19* 1.24* 1.19* 1.23* 1.05 1.09* 1.49* 1.46* 1.47* 1.43*

Intervention B 1.43* 1.48* 1.03 1.06 1.03 1.05 0.93* 0.94 1.26* 1.25* 1.45* 1.38*

Intervention C 0.99 0.98 1.05 1.04 1.04 1.04 0.96 0.93 1.18* 1.14 1.37* 1.39*

Intervention D 1.08* 1.10* 0.98 1.00 0.97 1.00 0.93* 0.94 1.05 1.11 1.04 1.09

Separate contamination variable:

Contaminated

(ref:

uncontaminated)

0.98i 0.95* 1.04* 1.01 1.06* 1.04* 1.09* 1.07* 1.04 1.05 0.98 0.97

*P value < 0.05

i Results for version 4 of the univariate model are for the intervention group and contamination variables modelled separately in different univariate models

14

Contamination sensitivity analysis

During the 6 week analysis a possible contamination was identified, whereby invitees in the posted

intervention groups (A, B and C) from Health Boards where outdoor advertising (D) was run (Cardiff

& Vale, Aneurin Bevan, and spilling over into Cwm Taf) potentially could have been exposed to the

advertising, despite being in another intervention group. Seeing the advertising could have

potentially increased their likelihood of returning the kits and therefore impacted the results for

interventions A, B, C, and controls. For example, an invitee in intervention group C in Cardiff & Vale

who was sent their gFOBT kit on 27th February 2015 could have delayed returning their kit until

after the advertising campaign began in the area on 16th March. They could have seen the

advertising, and then returned their kit in time to be counted as screened (i.e. within the 6 weeks

following the date they were sent the kit). A similar situation applies to those invited in the

advertising Health Boards before or after the advertising campaign was run, who would otherwise

have been included in the control group.

At the 6 week analysis, contamination was accounted for by including contaminated invitees in their

original intervention groups, and adding a separate binary contamination variable to account for any

additional effect on uptake caused by being contaminated by advertising (see Table 3, model

versions 4i, 4ii, and 4iii).

However, at the final 12 week analysis, model results showed that when ethnicity was included, the

binary contamination variable was not significant in two of the three models. Moreover, ethnicity

and the contamination variable were correlated (see Appendix 11). The two were likely collinear, as

Health Boards where contamination was possible (those where advertising took place or spilled into

– Cardiff & Vale, Aneurin Bevan, and Cwm Taf) are also Health Boards with lower percentages of

white residents. This suggested that the contamination variable was not working as effectively as

intended, and was removed from the final models in favour of the ethnicity variable, despite its

limitations as a proxy.

Table 3 shows a sensitivity analysis of the possible 12 week models, which all include ethnicity as a

predictor variable.

Model version 1) used all invitees, including contaminated invitees.

In version 2) we re-ran the model but excluded contaminated invitees from the analysis completely.

Contaminated invitees were defined as any people who were invited from the two advertising

campaign Health Boards (Cardiff & Vale and Aneurin Bevan), unless they were part of intervention D

(i.e. sent kits during the advertising campaign weeks from 20th March to 24th April 2015). People

invited at any time in the advertising overspill Health Board (Cwm Taf) were also defined as

contaminated.

Version 3) included all invitees in the model, but the contaminated invitees identified in version 2)

were moved to a separate “contaminated” intervention group.

Finally, version 4) also included all invitees in the model, but the contaminated invitees were kept in

their original intervention groups as in 1) and 2). Meanwhile, a separate binary contamination

variable was included in the model to account for any additional effect on uptake of being

contaminated by advertising.

Removing the contamination variable had limited impact on the overall results for the interventions,

so final 12 week results have used models 1di, 1dii and 1diii.

15

RESULTS Final analyses of uptake at 12 weeks after invitation (using models 1di, 1dii and 1diii shown in Table

3) show that, in Wales, the interventions had substantially different impacts in different screening

history groups. See Table 4 for results, also Appendix 7 for odds ratios):

• Overall, intervention A (CRUK endorsement letter) had the largest impact of all of the

interventions in each of the screening history groups; first-timers (9.1% absolute increase)

,previous non-responders (2.6% increase), and previously screened (1.4% increase).

• Intervention B also increased uptake in first-timers (5.5% increase) and non-responders (2.3%

increase).

• Further segmentation of results showed that amongst more deprived non-responders,

intervention B (CRUK endorsement letter + kit enhancement pack with gloves) was the

intervention with the largest impact on uptake (3.2% increase) (see Appendix 8 & 9 for odds

ratios). The impact of intervention B was larger still amongst more deprived non-responders

who were male (3.9% increase) (see Appendix 10 for odds ratios).

• Intervention C increased uptake in non-responders (2.4% increase) only.

• Intervention D (advertising only) did not increase uptake in any of the screening history

groups, and uptake was significantly lower in intervention D amongst previously screened

invitees (1.6% decrease).

TABLE 4: INITIAL 6-WEEK AND FINAL 12-WEEK UPTAKE RESULTS

AMONGST 60-74 YEAR OLDS, BY SCREENING HISTORY GROUP Intervention Previously screened First-timers Non-responders

6 Weeks 12 Weeks 6 Weeks 12 Weeks 6 Weeks 12 Weeks

Modelled uptake in controls 70.1% 76.7% 32.3% 36.1% 5.9% 6.6%

Percentage point increase in uptake compared to controls:

Intervention A +1.0% +1.4%* +9.3%* +9.1%* +2.5%* +2.6%*

CRUK endorsement letter

Intervention B

-1.5%* -0.9% +5.3%* +5.5%* +2.4%* +2.3%* CRUK endorsement letter +

pack (gloves)

Intervention C

-1.0% -1.2% +3.6%* +3.1% +2.0%* +2.4%* CRUK endorsement letter +

pack (gloves & poo-catcher)

Intervention D -1.5%* -1.6%* +1.1% +1.9% 0.2% +0.7%

Advertising only

Table shows the modelled underlying uptake amongst controls, followed by the absolute (percentage point)

increase in uptake in each intervention group compared to controls.

* indicates that the difference was statistically significant at a 95% confidence level.

16

DISCUSSION Results suggest that a personalised CRUK endorsement letter (A) can increase gFOBT uptake across

all screening history groups in Wales. It was particularly effective amongst those being invited for

the first time (9.1% absolute increase), potentially by providing this group with further information

and context, and an additional prompt to complete the NHS test kit. CRUK endorsement of bowel

screening was substantially more successful in Wales than in the previous pilot in London, where it

was sent as a flyer in the same mailing as the NHS FOBT kit, rather than as a separate personalised

letter. The flyer may have been less noticeable than the letter as it was included in the same mailing

as the NHS FOBT kit alongside the other materials routinely sent10. It should also be noted that at the

time in Wales, invitees did not receive pre-invitation letters before the actual NHS test kit, as was

the case in London. This could increase the value of adding another point of contact or reminder to

the process in Wales, however further research is needed to check whether the CRUK endorsement

letter is still effective in other contexts, e.g. where people are sent pre-invitation letters.

The CRUK endorsement letter plus gloves (B) increased uptake amongst first-timers (5.5% absolute

increase) and non-responders (2.3% absolute increase). Amongst non-responders from deprived

areas, it was also the intervention with the largest impact on uptake (3.2% absolute increase). The

gloves could therefore be potentially addressing some of the barriers to completion of the test for

people who have not completed it before; such as perceptions that handling faeces will be

unpleasant or disgusting.3 Further research could confirm and explore how the enhancement pack

with gloves may address barriers specific to more deprived non-responders.

The CRUK endorsement letter plus gloves and poo catchers (C) increased gFOBT uptake amongst

non-responders only (2.4% absolute increase), and did not have a bigger impact than sending the

CRUK endorsement letter plus gloves only (B). This suggests that including the poo catchers in the kit

does not have an additional impact on invitees.

Advertising alone (D) did not increase uptake in any screening history group, and uptake was lower

amongst previously screened invitees in the advertising intervention group compared to controls

(1.6% absolute decrease). Follow-up qualitative research was commissioned by CRUK and conducted

by Beaufort to further investigate this (see appendix 12 for more information). Focus groups with

previously screened participants (as well as with non-responders and those yet to be invited, i.e. 55

– 59 year olds) did not identify any elements of the advertising that discouraged participation.

However, some suggestions were made for improvements to the posters:

• A more direct, personal call-to-action that goes further to addressing barriers, particularly

amongst non-responders (e.g. worry about the results, or feelings that the kit will be

“unpleasant” to complete). However, these improvements would need to be considered

alongside the need to support an individual’s informed choice.

• A focus on communicating essential information about the kit and programme to raise

awareness and knowledge (requested by those yet to be invited).

A possible reason for the observed decrease in uptake amongst previously screened invitees in the

advertising intervention group could be due to factors that could not be accounted for in the

analysis. Controls were sourced from across Wales, whereas the advertising ran only in Aneurin

Bevan and Cardiff & Vale Health Boards. Whilst other factors such as deprivation, ethnicity (proxy),

gender and age were controlled for in the analysis, it is possible that the characteristics of people

living in these Health Boards may further differ from the rest of Wales (e.g. proficiency in English,

social grade, education, differences between urban and rural services). Furthermore, whilst the

effect of contamination of controls by advertising over time has been examined, the effect of

17

contamination over space has not been controlled for (i.e. controls from other parts of Wales may

have travelled into Cardiff or Newport and been impacted by advertising).

It is important to note that other local contexts can also influence the effectiveness of out of home

advertising campaigns; such as the number of opportunities for adverts (e.g. number of bus stops),

population density and commute patterns, newspaper readership, and saturation of the advertising

landscape by competing campaigns.

18

CONCLUSIONS

The CRUK endorsement letter (A) was the most effective intervention, increasing uptake across all

the screening history groups. The results suggest that a targeted approach would be most beneficial

in helping to reduce inequalities in Wales:

• The CRUK endorsement letter (A) could be sent to first-timers only, as it had a large impact

in this group (+9.1%).

• The CRUK endorsement letter plus gloves (B) could be sent to non-responders in more

deprived groups, as it had the largest impact of any intervention in this hard-to-engage

group (+3.2%).

Improvements could also be made to the CRUK advertising materials (D); for example by striving to

focus messaging towards the information needs of first timers and non-responders specifically.

19

END NOTES

1. Based on the annual average number of bowel cancer (ICD10 C18-20) cases (2013) and

deaths (2014) in Wales

2. Bowel Screening Wales Annual Statistical Report, 2014-15

3. Hewitson P et al (2007) “Screening for colorectal cancer using the faecal occult blood test

Hemmoccult.” Cochrane Database System Review.

4. D. M. Parkin, P. Tappenden, A. H. Olsen, J. Patnick, and P. Sasieni (2008) “Predicting the

impact of the screening programme for colorectal cancer in the UK,” Journal of Medical

Screening, vol.15, no. 4, pp. 163–174.

5. Miles, A., Rainbow, A. & von Wagner, C. (2011) “Cancer fatalism and poor self-rated health

mediate the association between socioeconomic status and uptake of colorectal cancer

screening in England.” Cancer Epidemiol Biomarkers Prev.

6. Palmer, C., Thomas, M., Von Wagner, C. & Raine, R. (2014) “Reasons for non-uptake and

subsequent participation in the NHS bowel cancer screening programme: a qualitative

study.” BJC.

7. Ekberg M, Callender M, Hamer H & Rogers S (2014) “Exploring the decision to participate in

the National Health Service Bowel Cancer Screening Programme.” Eur J Cancer Prevention.

8. Chapple, A., Ziebland, S., Hewitson, P. & McPherson, A. (2008) “What affects the uptake of

screening for bowel cancer using a faecal occult blood test (FOBt): a qualitative study.” Soc

Sci Med.

9. O’Sullivan, I. & Orbell, S. (2004) “Self-sampling to reduce mortality from colorectal cancer: a

qualitative exploration of the decision to complete a faecal occult blood test (FOBT).”

Journal of Medical Screening.

10. Hall, N., Rubin, G., Dobson, C., Weller, D., Wardle, J., Ritchie, M. & Rees, C. (2013) “Attitudes

and beliefs of non-participants in a population-based screening programme for colorectal

cancer. Health Expectations.”

11. von Wagner, C., Good, A., Smith, S. & Wardle, J. (2011) “Responses to procedural

information about colorectal cancer screening using faecal occult blood testing: the role of

consideration of future consequences.” Health Expectations.

12. Bennett, K., von Wagner, C. & Robb, K. (2015) “Supplementing factual information with

patient narratives in the cancer screening context: a qualitative study of acceptability and

preferences.” Health Expectations.

13. Cancer Research UK: Evidence on increasing bowel cancer screening uptake.

http://www.cancerresearchuk.org/healthprofessional/early-diagnosis-activities/bowel-

screening-projects-and-resources

14. B. White, E. Power, M. Ciurej, S. Hing Lo, K. Nash, N. Ormiston-Smith (2015) “Piloting the

Impact of Three Interventions on Guaiac Faecal Occult Blood Test Uptake within the NHS

Bowel Cancer Screening Programme.” BioMed Research International, Article ID 928251.

20

APPENDICES

Appendix 1: Examples of intervention materials

Intervention A: A4, 2pp endorsement letter, sent 3 days following the NHS test kit

Intervention B: CRUK endorsement letter + x1 kit enhancement pack containing x3 pairs of latex free

gloves

21

Intervention C: CRUK endorsement letter + x3 kit enhancement packs, each containing x1 pair of

gloves and x1 poo catcher

Intervention D: Advertising only

22

Appendix 2: Detailed breakdown of intervention costs

Invoices1

Invoice

costs

Intervention A:

CRUK

endorsement

letter

Intervention B:

CRUK

endorsement

letter plus pack

with gloves

Intervention C:

CRUK endorsement

letter plus pack

with gloves & poo-

catchers

Intervention D:

Advertising

only

Set up costs

Design costs - updates to OOH creative, press and letters2 £6,042.00 £150.00 £150.00 £150.00 £5,592.00

Additional layout and artwork of bus formats £1,050.00 £1,050.00

Additional layout and artwork of bus formats - extra £180.00 £180.00

Welsh translations £60.00 £20.00 £20.00 £20.00

Ongoing costs

A3 & A4 posters £892.00 £892.00

Mediacom (press) £5,670.00 £5,670.00

Mediacom (press) £4,063.50 £4,063.50

Mediacom (bus panels) £8,555.86 £8,555.86

Mediacom (washrooms) £4,140.51 £4,140.51

Mediacom (6s & 48s) £38,983.04 £38,983.04

Set up, testing fees and print production of direct mail £9,307.00 £3,102.33 £3,102.33 £3,102.33

Full kits (gloves + poo catchers) x5,500 £17,570.00 £10,618.46

Gloves only kits x5,500 £5,235.55

Extra 6000 poo catchers £1,716.00

Additional full packs (gloves & poo catcher) and packs with gloves only

(2000 of each type of pack = 4,000 packs in total)3 £1,683.00 £841.50 £841.50

Additional production & fulfilment associated with intervention A, week two

re-print (2000)4 £1,142.00 £1,142.00

23

OS C5 envelopes (24,500) £1,054.00 £351.33 £351.33 £351.33

Additional C5 envelopes (7000) £779.00 £259.66 £259.66 £259.66

Destroying incorrect intervention A mailings & re-print of week two letters4 £326.00 £326.00

Courier £29.00 £29.00

Postage (split across interventions is estimated)5 £6,915.00 £2,000.00 £2,457.50 £2,457.50

Total £108,441.91 £7,380.32 £12,417.87 £19,516.78 £69,126.91

Costs per engagement (for sample included in final analysis) £0.83 £1.78 £2.80 £6.23

Total sample that received intervention (i.e. mailed direct mail or estimated

to have been exposed to advertising) 9,300 7,300 7,300 11,094

Total sample included in final analysis6 8,875 6,995 6,981 11,094

1 Note the above table excludes evaluation costs

2 This is an estimated split of design costs across the interventions

3 Packs with gloves & poo catchers will have cost more than packs with gloves only. Exact cost breakdown unknown.

4 Excluded from cost effectiveness analysis as costs are due to an error

5 This is an estimated split of postage costs across the three interventions

6 Number for intervention D does not differ to no. receiving intervention, as the group identified as having been exposed to advertising is an estimate established at the

analysis stage

24

Appendix 3: Intervention allocations by week

Week

number

in

analysis

Call run

(Friday)

Kits sent

(following

Friday)

Total

invitees

sent kit

in week

Intervention

group

allocation

Date mailed

intervention/

advertising

ran

Notes

325 09/01/2015 16/01/2015 8527 Control week NA No invitees sent interventions

326 16/01/2015 23/01/2015 5028 Control week NA above

327 23/01/2015 30/01/2015 3248 Intervention

A (error

week)i

02/02/2015 All invitees sent intervention A

328 30/01/2015 06/02/2015 4896 Intervention

A + controls

09/02/2015 Additional invitees sent

intervention A to reach sample

size. All other invites were

controls.

329 06/02/2015 13/02/2015 5035 Intervention

B

16/02/2015 All invitees sent intervention B

330 13/02/2015 20/02/2015 3573 Intervention

B + controls


intervention B to reach sample


controls.

331 20/02/2015 27/02/2015 5226 Intervention

C

02/03/2015 All invitees sent intervention C

332 27/02/2015 06/03/2015 5077 Intervention

C + controls


intervention C to reach sample


controls.

333 06/03/2015 13/03/2015 5085 Controls NA No invitees sent interventions

334 13/03/2015 20/03/2015 4683 Intervention

D

(advertising)

+ controls

16/03/2015 -

26/04/15

Advertising in ABU & CVUii.

Invites in all other Health Boards

were controls.

335 20/03/2015 27/03/2015 5314 Intervention

D

(advertising)

+ controls

16/03/2015 -

26/04/15

As above

336 27/03/2015 03/04/2015 6443 Intervention

D

(advertising)

+ controls

16/03/2015 -

26/04/15

As above

337 02/04/2015

(due to bank

holiday)

10/04/2015 1617 Intervention

D

(advertising)

+ controls

16/03/2015 -

26/04/15

As above

25

338 10/04/2015 17/04/2015 5972 Intervention

A rerun/

Intervention

D

(advertising)

+ controls

Intervention A

sent on

20/04/15.

Advertising

16/03/2015 -

26/04/15 in

ABU & CVU

Additional invitees were sent

intervention A to reach sample

size, due to an error in the first

intervention A week (kits sent

30/01/15).i Intervention A was

not sent to ABU, CVU Health

Boards, where advertising ran,

and CTUii where there was some

overspill of advertising. Those

sent kits in ABU & CVU Health

Boards were allocated to

intervention D (advertising) as

with previous weeks.

339 17/04/2015 24/04/2015 7745 Intervention

D

(advertising)

+ controls

16/03/2015 -

26/04/15

Advertising in ABU & CVUii.

Invites in all other Health Boards

were controls.






i There was an error on the endorsement letters sent in the first week of intervention A (intervention mailed 02/02/15),

where addressees’ first names and last names were in the incorrect order. Intervention A was therefore rerun after the

advertising had finished (intervention mailed 20/04/15), to ensure an adequate sample of invitees sent the correctly

addressed endorsement letters.

ii Aneurin Bevan (ABU), Cardiff & Vale (CVU), Cwm Taf (CTU).

26

Appendix 4: Power calculations for intervention target sample sizes

Calculations are based on this online tool: http://www.stat.ubc.ca/~rollin/stats/ssize/b2.html

Calculations assume a baseline uptake of 50%.

If the impact of the campaign were to be X% with significance of 5% and a power of 80% and a

two sided test then the sample size would need to be:

Baseline uptake Difference

aiming to see

Uptake after

the campaign

Minimum

sample size

required

50% 1% 51% 39240

50% 3% 53% 4356

50% 3.25% 53.25% 3711

50% 5% 55% 1565

50% 7% 57% 796

50% 10% 60% 388

Therefore in order to detect a 3% increase in uptake it is necessary that each intervention group has

a minimum of 4,356 observations.

27

Appendix 5: Metadata for variables included in dataset

Variable name Type Description Categories

AgeInvite Integer Individual’s age at invite (i.e. when

sent kit).

0: 60

Max value: 74

ageinvite_cat_3 Categorical As above 0: 60-63

1: 64-66

2: 67-74

gender_cat Categorical Gender 0: M (Male)

1: F (Female)

2: U (Indeterminate)

sxhistory_incid

ent

Binary Screening history of individual –

whether they have been adequately

screened before

0: Prevalent (never been screened

before)

1: Incidence (previously screened

at least once)

sxhistory_cat Categorical Screening history of individual –

previously screened, first-timer, non

responder

0: I (Incident i.e. previously

screened at least once)

1: P1 (First Prevalent Round i.e.

first-timer)

2: P2 (Subsequent Prevalent

Round i.e. non-responder)

HB_cat Categorical Individual’s Health Board of residence

when invited

0: ABMU (Abertawe Bro

Morgannwg)

1: ABU (Aneurin Bevan)

2: BCU (Besti Cadwaladr)

3: C&VU (Cardiff & Vale)

4: CTU (Cwm Taf)

5: HDU (Hywel Dda)

6: PT (Powys)

7: Unknown

WeekRecall Integer The week that the individual was sent

a kit

0: 325 (first week included in data,

i.e. kits sent 16/01/2015

Max value: 344 (final week

included in data, i.e. kit sent

29/05/2015)

INT_cat Categorical Allocated intervention group 0: Control

1: Intervention A

2: Intervention B

3: Intervention C

4: Intervention D (if living in C&VU

or ABU and invited between

weeks 333 and 339 i.e. the

advertising period)

Contaminated_

cat_hbonly

Binary Flag to state whether the individual

was sent kit at a time and place when

they could have been contaminated

(i.e. exposed to advertising).

Individuals allocated to intervention D

are not marked as contaminated.

Variable performs similar function to

intervention_contam.

0: No (not contaminated)

1: Yes (contaminated - any case or

control living in CTU, or invited

from C&VU or ABU and not

invited between weeks 333 and

339).

WIMDscore Continuous Area level estimate of the individual’s

Welsh Index of Multiple Deprivation

(WIMD) rank, based on their LSOA

(Lower Super Output Area) of

residence.

1: Most deprived LSOA in Wales

1897: Least deprived LSOA in

Wales

imd_quintile Categorical Area level estimate of the individual’s

Welsh Index of Multiple Deprivation

1: Rank 1517 to 1897 (least

deprived quintile)

28

(WIMD) quintile, based on their LSOA

(Lower Super Output Area) of

residence.

2: Rank 1138 to 1516

3: Rank 759 to 1137

4: Rank 380 to 758

5: Rank 1 to 379 (most deprived

quintile)

Eligible Binary Flag of whether the individual was

eligible for inclusion in uptake figures.

For example, if individual died or

moved away since they were sent their

kit and they didn’t respond, they are

not counted as eligible.

1: Yes

2: No

Responded_use

d

Binary Whether the individual was

adequately screened within 6 weeks

after being sent their kit (i.e.

responded with used test kit)

0: No

1: Yes

whiteperc_quin

tile

Categorical An area level proxy for ethnicity; using

the percentage of the residents in the

individual’s LSOA (Lower Super Output

Area) that are white vs non-white

(according to 2011 census).

1: 35% (minimum value) - 96.1%

white (Quintile with lowest

proportion of white residents in

LSOA)

2: 96.2% - 97.7% white

3: 97.8% - 98.5% white

4: 98.6% - 98.9% white

5: 99.0% - 99.9% (maximum value)

white (Quintile with highest

proportion of white residents in

LSOA)

29

Appendix 6: Univariate logistic regression results

• Intervention group: Uptake was significantly higher amongst invitees in intervention groups A, B and D,

compared to controls. Uptake in intervention group C was not significantly different to controls.

• Age group: Descriptive analysis showed that uptake increased with age from 60 years, but plateaued from

67 to 74 years. The age at invite variable was therefore recoded into a categorical variable with three age

groups. Uptake amongst invitees aged 64-66 and 67-74 were both significantly higher than those aged 60-

63.

• Screening history: Uptake was significantly lower amongst “first-timers” (people who were being invited

to bowel screening for the first time), and amongst “non-responders” (people who had been invited to

bowel screening before and never responded), compared to previously screened invitees.

• Gender: Uptake was significantly higher in females than males.

• Deprivation: The odds of uptake significantly increased with decreasing levels of deprivation (i.e. as Welsh

Index of Multiple Deprivation (WIMD) score increased). Final multivariate analysis used WIMD quintile

groups, for ease of communication of results.

• Health Board: Uptake was significantly lower in Cardiff & Vale, compared to the reference Health Board

(Abertawe Bro Morgannwg) (not shown).

• Week of invitation: There was large variation in uptake by week, but with no obvious trend over time (not

shown).

• Ethnicity (12 week analysis): as the percentage of residents within an invitees’ LSOA (Lower Super Output

Area) that were white increased, their odds of uptake increased. This was categorised into quintiles for

the final analysis, both for ease of communication, and because the relationship plateaued at higher

percentages of white residents.

Responded at 6 weeks Odds ratio P value

95% lower

confidence limit

95% upper

confidence limit

Intervention group

Control group 1.00 (ref)

Intervention A 1.36 0.000 1.30 1.42

Intervention B 1.43 0.000 1.36 1.50

Intervention C 0.99 0.771 0.94 1.04

Intervention D 1.08 0.000 1.03 1.12

Previous screening history

Previously screened 1.00 (ref)

First-timer 0.22 0.000 0.21 0.23

Non-responder 0.03 0.000 0.03 0.03

Age at invite

60-63 1.00 (ref)

64-66 1.31 0.000 1.26 1.35

67-74 1.44 0.000 1.40 1.48

Welsh IMD Score (ref=0) 1.00 0.000 1.00 1.00

Gender

Male 1.00 (ref)

Female 1.28 0.000 1.25 1.31

Responded at 12 weeks Odds ratio P value

95% lower

confidence limit

95% upper

confidence limit

Ethnicity (% white) (ref=0) 1.02 0.001 1.02 1.02

30

Appendix 7: Stratified multivariate logistic regression results for gFOBT uptake at 12 weeks amongst 60-74 year olds

Responded at 12

weeks

Previously screened (N=48,102) First-timers (N=15,635) Non-responders (N=37,967

Odds ratio

Mean

(%) P value

95% lower

confidence

limit

95% upper

confidence

limit Odds ratio

Mean

(%) P value

95% lower

confidence

limit

95% upper

confidence

limit Odds ratio

Mean

(%) P value

95% lower

confidence

limit

95% upper

confidence

limit

Intervention

group

Control group 1.00 (ref) 1.00 (ref) 1.00 (ref)

Intervention A 1.09 0.10 0.028 1.01 1.17 1.46 0.06 0.000 1.28 1.67 1.43 0.08 0.000 1.26 1.62

Intervention B 0.95 0.09 0.179 0.88 1.02 1.26 0.05 0.003 1.08 1.47 1.38 0.05 0.000 1.18 1.61

Intervention C 0.94 0.07 0.134 0.86 1.02 1.14 0.05 0.082 0.98 1.33 1.39 0.08 0.000 1.21 1.60

Intervention D 0.92 0.11 0.012 0.86 0.98 1.09 0.11 0.135 0.97 1.21 1.11 0.10 0.111 0.98 1.26

Age at invite

60-63 1.00 (ref) 1.00 (ref) 1.00 (ref)

64-66 0.95 0.27 0.123 0.88 1.02 1.34 0.02 0.009 1.08 1.68 0.54 0.27 0.000 0.49 0.59

67-74 0.92 0.59 0.013 0.86 0.98 0.91 0.04 0.3 0.76 1.09 0.33 0.50 0.000 0.30 0.36

Welsh IMD

Quintile

1 - Least deprived 1.00 (ref) 1.00 (ref) 1.00 (ref)

2 0.91 0.23 0.005 0.86 0.97 0.82 0.21 0.000 0.75 0.91 0.92 0.21 0.167 0.82 1.04

3 0.85 0.22 0 0.79 0.90 0.79 0.21 0.000 0.72 0.88 0.84 0.21 0.005 0.75 0.95

4 0.81 0.18 0 0.75 0.86 0.76 0.19 0.000 0.68 0.84 0.81 0.20 0.000 0.72 0.91

31

5 - Most deprived 0.72 0.14 0 0.67 0.77 0.61 0.16 0.000 0.54 0.68 0.73 0.19 0.000 0.64 0.83

Ethnicity (%

white)

1 - Least white % 1.00 (ref) 1.00 (ref) 1.00 (ref)

2 1.04 0.20 0.263 0.97 1.11 1.12 0.20 0.035 1.01 1.24 1.07 0.20 0.278 0.95 1.20

3 1.05 0.24 0.14 0.98 1.12 1.09 0.23 0.086 0.99 1.21 1.02 0.23 0.690 0.91 1.15

4 1.10 0.18 0.012 1.02 1.18 1.13 0.17 0.029 1.01 1.26 1.09 0.16 0.165 0.96 1.24

5 - Most white % 1.04 0.20 0.258 0.97 1.12 1.14 0.19 0.019 1.02 1.27 1.05 0.18 0.412 0.93 1.19

Gender

Male 1.00 (ref) 1.00 (ref) 1.00 (ref)

Female 1.08 0.54 0.001 1.03 1.12 1.45 0.51 0.000 1.36 1.55 0.92 0.47 0.025 0.85 0.99

Constant 3.70 0.000 3.39 4.04 0.54 0.000 0.48 0.59 0.17 0.000 0.15 0.20

32

Appendix 8: Stratified multivariate logistic regression results for gFOBT uptake at 12weeks amongst 60-74 year olds,

restricted to less deprived invitees only (WIMD quintiles 1-3)

Responded at 12

weeks

Previously screened (N=32,871) First-timers (N=10,050) Non-responders (N=22,981)

Odds ratio

Mean

(%) P value

95% lower

confidence

limit

95% upper

confidence

limit Odds ratio

Mean

(%) P value

95% lower

confidence

limit

95% upper

confidence

limit Odds ratio

Mean

(%) P value

95% lower

confidence

limit

95% upper

confidence

limit

Intervention

group


Intervention A 1.18 0.10 0 1.08 1.29 1.43 0.06 0.000 1.21 1.68 1.44 0.08 0.000 1.23 1.68

Intervention B 0.94 0.09 0.199 0.86 1.03 1.20 0.04 0.063 0.99 1.46 1.25 0.05 0.028 1.02 1.53

Intervention C 0.92 0.07 0.134 0.83 1.02 1.14 0.05 0.157 0.95 1.38 1.38 0.08 0.000 1.16 1.63

Intervention D 0.91 0.11 0.033 0.84 0.99 1.15 0.11 0.038 1.01 1.31 1.13 0.10 0.124 0.97 1.33

Age at invite

60-63 1.00 (ref) 1.00 (ref) 1.00 (ref)

64-66 1.02 0.27 0.635 0.94 1.11 1.18 0.02 0.218 0.91 1.52 0.54 0.27 0.000 0.48 0.61

67-74 1.00 0.59 0.975 0.93 1.08 0.78 0.04 0.018 0.63 0.96 0.34 0.50 0.000 0.31 0.38

Welsh IMD

Quintile

1 - Least deprived 1.00 (ref) 1.00 (ref) 1.00 (ref)

2 0.92 0.34 0.01 0.86 0.98 0.83 0.33 0.000 0.75 0.92 0.93 0.34 0.202 0.82 1.04

3 0.85 0.32 0 0.80 0.91 0.80 0.33 0.000 0.72 0.88 0.85 0.35 0.007 0.76 0.96

33

Ethnicity (%

white)


2 1.00 0.20 0.984 0.92 1.09 1.22 0.19 0.003 1.07 1.40 1.01 0.20 0.914 0.87 1.18

3 1.02 0.24 0.591 0.94 1.12 1.13 0.24 0.075 0.99 1.28 0.94 0.23 0.387 0.80 1.09

4 1.07 0.18 0.142 0.98 1.17 1.21 0.18 0.006 1.06 1.40 1.05 0.17 0.569 0.89 1.23

5 - Most white % 0.97 0.22 0.542 0.89 1.06 1.13 0.22 0.072 0.99 1.29 1.03 0.22 0.676 0.89 1.20

Gender

Male 1.00 (ref) 1.00 (ref) 1.00 (ref)

Female 1.11 0.55 0.000 1.06 1.17 1.48 0.51 0.000 1.36 1.60 1.04 0.46 0.437 0.94 1.14

Constant 3.48 0.000 3.14 3.86 0.51 0.000 0.45 0.58 0.17 0.000 0.14 0.19

34

Appendix 9: Stratified multivariate logistic regression results for gFOBT uptake at 12 weeks amongst 60-74 year olds,

restricted to more deprived invitees only (WIMD quintiles 4-5)

Responded at 12

weeks


Odds ratio

Mean

(%) P value

95% lower

confidence

limit

95% upper

confidence

limit Odds ratio

Mean

(%) P value

95% lower

confidence

limit

95% upper

confidence

limit Odds ratio

Mean

(%) P value

95% lower

confidence

limit

95% upper

confidence

limit

Intervention

group


Intervention A 0.92 0.09 0.189 0.81 1.04 1.51 0.06 0.000 1.21 1.89 1.41 0.08 0.002 1.14 1.75

Intervention B 0.97 0.08 0.607 0.85 1.10 1.34 0.05 0.019 1.05 1.70 1.60 0.05 0.000 1.25 2.06

Intervention C 0.96 0.07 0.635 0.83 1.12 1.15 0.05 0.274 0.89 1.48 1.41 0.08 0.004 1.12 1.77

Intervention D 0.92 0.12 0.131 0.82 1.03 0.95 0.11 0.629 0.79 1.15 1.07 0.11 0.506 0.87 1.33

Age at invite

60-63 1.00 (ref) 1.00 (ref) 1.00 (ref)

64-66 0.80 0.28 0.001 0.71 0.91 2.00 0.02 0.002 1.30 3.08 0.52 0.28 0.000 0.45 0.61

67-74 0.77 0.59 0.000 0.69 0.87 1.45 0.03 0.034 1.03 2.04 0.32 0.50 0.000 0.27 0.37

Welsh IMD

Quintile

4 1.00 (ref) 1.00 (ref) 1.00 (ref)

5 - Most deprived 0.90 0.43 0.005 0.83 0.97 0.81 0.46 0.000 0.72 0.91 0.91 0.49 0.163 0.80 1.04

35

Ethnicity (%

white)


2 1.10 0.21 0.091 0.98 1.23 0.96 0.22 0.654 0.82 1.14 1.14 0.21 0.156 0.95 1.38

3 1.09 0.23 0.130 0.98 1.21 1.06 0.22 0.472 0.90 1.25 1.18 0.22 0.077 0.98 1.42

4 1.12 0.17 0.055 1.00 1.26 1.01 0.15 0.919 0.84 1.21 1.15 0.15 0.177 0.94 1.41

5 - Most white % 1.19 0.16 0.004 1.06 1.35 1.27 0.13 0.014 1.05 1.53 1.04 0.14 0.709 0.84 1.30

Gender

Male 1.00 (ref) 1.00 (ref) 1.00 (ref)

Female 1.02 0.54 0.683 0.94 1.09 1.40 0.50 0.000 1.25 1.57 0.73 0.48 0.000 0.64 0.83

Constant 3.45 0.000 2.99 3.97 0.42 0.000 0.36 0.49 0.15 0.000 0.12 0.18

36

Appendix 10: Stratified multivariate logistic regression results for gFOBT uptake at 12 weeks amongst 60-74 year olds,

restricted to more deprived males only (WIMD quintiles 4-5)

Responded at 12

weeks


Odds ratio

Mean

(%) P value

95% lower

confidence

limit

95% upper

confidence

limit Odds ratio

Mean

(%) P value

95% lower

confidence

limit

95% upper

confidence

limit Odds ratio

Mean

(%) P value

95% lower

confidence

limit

95% upper

confidence

limit

Intervention

group


Intervention A 0.90 0.09 0.256 0.75 1.08 1.42 0.06 0.032 1.03 1.96 1.50 0.07 0.004 1.14 1.98

Intervention B 1.00 0.09 0.982 0.83 1.22 1.44 0.05 0.039 1.02 2.04 1.64 0.05 0.002 1.19 2.26

Intervention C 0.92 0.07 0.438 0.74 1.14 1.42 0.04 0.086 0.95 2.11 1.53 0.08 0.004 1.14 2.05

Intervention D 0.84 0.12 0.034 0.71 0.99 1.15 0.11 0.291 0.88 1.50 1.12 0.11 0.422 0.85 1.47

Age at invite

60-63 1.00 (ref) 1.00 (ref) 1.00 (ref)

64-66 0.80 0.28 0.018 0.67 0.96 2.36 0.02 0.004 1.32 4.22 0.63 0.30 0.000 0.51 0.77

67-74 0.89 0.59 0.188 0.76 1.06 1.54 0.02 0.085 0.94 2.53 0.36 0.48 0.000 0.29 0.44

Ethnicity (%

white)


2 0.99 0.21 0.865 0.84 1.16 0.95 0.21 0.657 0.74 1.21 1.29 0.22 0.038 1.01 1.64

3 1.03 0.23 0.758 0.87 1.20 1.14 0.22 0.267 0.90 1.44 1.20 0.21 0.136 0.94 1.53

37

4 0.95 0.17 0.546 0.80 1.12 1.18 0.16 0.199 0.92 1.53 1.40 0.15 0.013 1.07 1.81

5 - Most white % 1.20 0.16 0.042 1.01 1.44 1.36 0.13 0.027 1.04 1.78 1.19 0.14 0.21 0.91 1.57

Constant 3.27 0.000 2.71 3.94 0.35 0.000 0.30 0.42 0.12 0.000 0.09 0.14

38

Appendix 11: Collinearity between ethnicity proxy & contamination

variable

Regression of ethnicity proxy and contamination variable show the two were correlated. The results show the

percentage of white residents within an invitee’s LSOA (Lower Super Output Area) is lower amongst

contaminated cases than uncontaminated cases:

regress c.whiteperc i.contaminated_cat_hbonly

Source SS df MS

Model 82129.6057 1 82129.61

Residual 3120364.311 29.29892

Total 3202493.921 30.0698

Number of obs = 106503

F( 1,106501) = 2803.16

Prob > F = 0.0000

R-squared = 0.0256

Adj R-squared = 0.0256

Root MSE = 5.4128

Percentage white residents

within LSOA Coefficient P value

95% lower

confidence limit

95% upper confidence

limit

Contaminated cases -1.929946 0.000 -2.00139 -1.8585

Constant 97.06609 0.000 97.02743 97.10474

39

Appendix 11 continued: Stratified multivariate logistic regression results for gFOBT uptake at 12 weeks

amongst 60-74 year olds, including both ethnicity and separate contamination variable

Responded at 12 weeks


Odds ratio P value

95% lower

confidence

limit

95% upper

confidence

limit Odds ratio P value

95% lower

confidence

limit

95% upper

confidence

limit Odds ratio P value

95% lower

confidenc

e limit

95% upper

confidence

limit

Intervention group

Control group 1.00 1.00 1.00

Intervention A 1.09 0.028 1.01 1.17 1.46 0.000 1.28 1.67 1.43 0.000 1.26 1.62

Intervention B 0.94 0.140 0.88 1.02 1.25 0.004 1.08 1.46 1.38 0.000 1.18 1.61

Intervention C 0.93 0.099 0.86 1.01 1.14 0.091 0.98 1.32 1.39 0.000 1.21 1.60

Intervention D 0.94 0.085 0.88 1.01 1.11 0.079 0.99 1.24 1.09 0.183 0.96 1.25

Contamination

Uncontaminated 1.00 1.00 1.00

Contaminated 1.07 0.009 1.02 1.12 1.05 0.247 0.97 1.13 0.97 0.463 0.88 1.06

Age at invite

60-63 1.00 1.00 1.00

64-66 0.95 0.123 0.88 1.02 1.35 0.008 1.08 1.68 0.54 0.000 0.49 0.59

67-74 0.92 0.014 0.87 0.98 0.91 0.323 0.77 1.09 0.33 0.000 0.30 0.36

40

Welsh IMD Quintile

1 - Least deprived quintile 1.00 1.00 1.00

2 0.92 0.015 0.86 0.98 0.83 0.000 0.75 0.92 0.92 0.143 0.81 1.03

3 0.85 0.000 0.80 0.91 0.80 0.000 0.72 0.88 0.84 0.004 0.75 0.95

4 0.81 0.000 0.76 0.86 0.76 0.000 0.68 0.84 0.81 0.000 0.72 0.91

5 - Most deprived quintile 0.72 0.000 0.67 0.77 0.60 0.000 0.54 0.67 0.73 0.000 0.65 0.83

Ethnicity (% white)

1 - Least white % 1.00 1.00 1.00

2 1.05 0.168 0.98 1.12 1.13 0.025 1.01 1.25 1.06 0.329 0.94 1.20

3 1.06 0.069 1.00 1.14 1.10 0.061 1.00 1.22 1.02 0.784 0.90 1.14

4 1.11 0.005 1.03 1.19 1.14 0.021 1.02 1.27 1.09 0.204 0.96 1.23

5 - Most white % 1.06 0.110 0.99 1.14 1.15 0.011 1.03 1.29 1.04 0.520 0.92 1.18

Gender

Male 1.00 1.00 1.00

Female 1.08 0.001 1.03 1.12 1.45 0.000 1.36 1.55 0.92 0.026 0.85 0.99

Constant 3.57 0.000 3.26 3.92 0.52 0.000 0.47 0.58 0.17 0.000 0.15 0.20

41

Appendix 12: Follow up qualitative evaluation

Aims

Following the uptake analysis, further qualitative research was commissioned by CRUK and conducted by

Beaufort.

The primary aim was to explore reactions to the ad campaign amongst the three screening history groups, in

order to understand the observed decrease in uptake amongst previously screened invitees, and the lack of

impact amongst first-timers and non-responders.

Secondary aims included identifying improvements to the posters, and gathering further qualitative insight

about the motivations and concerns for these three different groups.

Methods

The following focus groups (N=36 participants) were conducted in January 2016, in two cities where the

campaign ran (Cardiff and Newport):

• 2x groups with previous responders (people aged 60-74 who said they had previously been invited

and returned a kit). One group was conducted with participants from ABC1 backgrounds, and the

other with participants from C2DE backgrounds.

• 1x group with non-responders (people aged 62-74 who said they had been invited before but not

returned their kit)

• 1x group with not-yet-invited (people aged 58-59 who said they had never been invited)

Groups included a mix of men and women, and also included 5 BME participants (African, and South Asian).

Due to difficulties recruiting non-responders, a small focus group (n=4) was run initially, which was

supplemented by a further paired depth interview with two BME non-responders.

Only participants from the target audience who could not recall seeing the adverts were recruited, in order to

best gauge initial reactions to the campaign.

Focus groups explored the following topic areas:

• Initial reaction to the poster

• Take out of main message/ call to action

• Perceived relevance of/ engagement with poster

• Perceived impact on behaviour

• Suggested improvements to poster

• Impact of CRUK branding

• Underlying attitudes towards the bowel screening test

Key findings

The focus groups did not identify any elements of the advertising that discouraged participation, as none of

the reactions or feedback indicated that the campaign would significantly affect screening behaviour in either

a positive or negative way. This conclusion is supported by the finding that the main message take out from

the campaign tended not to extend beyond the information that a kit is available. There is no evidence to

suggest that the characters used in the ads are creating an adverse reaction to the bowel screening kits. The

research did raise some suggestions for improvement and supported the need to further target the campaigns:

• Previous responders in this research were already mostly committed to screening, so the effect of the

ad was limited to reinforcing their current behaviour. Further investigation could be conducted to

establish effective messaging for intermittent responders.

• Non-responders may benefit from a more direct, personal call-to-action that goes further to

addressing barriers (e.g. worry about the results, or feelings that the kit will be “unpleasant” to

complete).

• Not-yet invited people require essential information about the kit and programme to be more

prominent, to raise their awareness and knowledge. For example, information about the age and how

often that they will receive the kit, and what they should do with it could be emphasised.

wales bowel cancer screening pilot ......letter plus the full kit enhancement pack (containing...

Documents