Surveys of Undiagnosed Surveys of Undiagnosed STIsSTIs

Bias due to Missing BiospecimensBias due to Missing Biospecimens

Charles Turner & Susan RogersCharles Turner & Susan Rogers

forfor

MSPP Research TeamMSPP Research Team

DisclosuresDisclosures

Neither author has personal financial relationships with commercial interests relevant to this presentation

Dr. Rogers is employed by and Dr. Turner is a consultant to the Research Triangle Institute (RTI).

RTI is a non-profit research organization that conducts surveys and other research for federal, state, and commercial clients.

Research SupportResearch Support

NIH grant R01-HD047163 from the National Institute of Child Health and Human Development

Monitoring STIs in the Monitoring STIs in the PopulationPopulation

Research TeamResearch Team

Susan Rogers, PI, Research Triangle InstituteSusan Rogers, PI, Research Triangle InstituteCharles Turner, Co-PI, CUNYCharles Turner, Co-PI, CUNYBill Miller, UNC School of MedicineBill Miller, UNC School of MedicineEmily Erbelding, JHU School of MedicineEmily Erbelding, JHU School of MedicineMarcia Hobbs, UNC School of MedicineMarcia Hobbs, UNC School of MedicineElizabeth Eggleston, Research Triangle Institute Elizabeth Eggleston, Research Triangle Institute Anthony Roman, University of MassachusettsAnthony Roman, University of MassachusettsSylvia Tan, Research Triangle InstituteSylvia Tan, Research Triangle InstituteJames Chromy, Research Triangle InstituteJames Chromy, Research Triangle Institute

Monitoring Monitoring Undiagnosed STIs in Undiagnosed STIs in

PopulationsPopulations

A New Paradigm for STI EpidemiologyA New Paradigm for STI Epidemiology

Focus simultaneously onFocus simultaneously on– diagnosed infections reported to DoHdiagnosed infections reported to DoH– undiagnosed infections prevalent in undiagnosed infections prevalent in

populationpopulation

OLD PARADIGMOLD PARADIGMTrack Diagnosed STIsTrack Diagnosed STIs

0

10

20

30

40

50

60

70

80

90

2005 2006 2007 2008

Diagnosed

NEW PARADIGMNEW PARADIGMTrack Both Diagnosed & Track Both Diagnosed &

Undiagnosed STIsUndiagnosed STIs

0

10

20

30

40

50

60

70

80

90

2005 2006 2007 2008

DiagnosedUndiagnosed

NEW PARADIGMNEW PARADIGMTrack Diagnosed & Track Diagnosed & Undiagnosed STIsUndiagnosed STIs

0

20

40

60

80

100

120

140

2005 2006 2007 2008

DiagnosedUndiagnosed

1998 Baltimore STD 1998 Baltimore STD and Behavior Surveyand Behavior Survey

In-person survey with biospecimens; Adults 18-35

79% biospecimen acceptance

7.9% prevalence of undiagnosed GC and/or CT; 15% among black females

Source: Turner, Rogers et al., JAMA, Feb. 13, 2002

1998 Baltimore STD 1998 Baltimore STD and Behavior Surveyand Behavior Survey

More Undiagnosed Infections than Annual Diagnosed Infections reported to DOH

MSPP Survey Program, MSPP Survey Program, 2006-20092006-2009 Adolescents and Adults in

Baltimore

Ages 15 to 35

Full probability sample

Fall 2006 thru Summer 2009

Survey ExecutionSurvey Execution

73,318 Telephone Numbers dialed

20,435 Households Identified

14,199 Households Screened

4,998 Eligible Respondents Identified

2,936 (59%) of Eligibles Interviewed

MeasurementsMeasurements

T-ACASI interviews on sexual behaviors and STI history

Biospecimens: Urine and Vaginal Swabs

NAAT testing for Chlamydia, Gonorrhea, and Trichomonas

BiospecimensBiospecimens

Biospecimens requested from All Survey Respondents

Mail-out and Mail-Back kits via US Postal Service

Monetary Incentive, $40 to $100

NAAT assays for Ct, GC, Tv

Biospecimen Biospecimen AcceptanceAcceptance

2,936 did 13-Minute Survey Interview

2,522 (86%) agreed to biospecimen

2,120 (72%) biospecimens received

Biospecimen Biospecimen NonResponseNonResponse 414 completed interview but

refused request for biospecimen

402 agreed but did not supply biospecimen despite repeated requests

Performance Improved Performance Improved with Experiencewith Experience

% supplying biospecimens% supplying biospecimens(linear p < 0.05)(linear p < 0.05)

60

65

70

75

80

Y-1 Y-2 Y-3

Equivalent Acceptance by Equivalent Acceptance by Gender, Race, Marital Gender, Race, Marital

StatusStatus% supplying biospecimens% supplying biospecimens

(all p > 0.40)(all p > 0.40)

0

10

20

30

40

50

60

70

80

Male vs.Female

Black vs.NonBlack

Marry, NvrMarry, D-W-S

Equivalent Acceptance Equivalent Acceptance Across Age Groups Across Age Groups

(p > 0.50)(p > 0.50)

0

10

20

30

40

50

60

70

80

15-17 18-25 26-34

AGE

Varied Slightly for Varied Slightly for Hispanics and by EducationHispanics and by Education

(HISP: p = 0.08; EDUC p = 0.02) (HISP: p = 0.08; EDUC p = 0.02)

01020

30405060

7080

Hispanic vs.Non_Hispanic

<HS, HSG, Some Coll,Coll+

Modest Variation by Modest Variation by Number of Sex Partners in Number of Sex Partners in

Past YearPast Year(Categorical: p = 0.09; Linear p > 0.50) (Categorical: p = 0.09; Linear p > 0.50)

0

10

20

30

40

50

60

70

80

0 1 2 3 4 5-10 11+

Number of Partners, 12 mo.

Equivalent Testing for Equivalent Testing for Respondents with Same-Respondents with Same-

Gender Sex History Gender Sex History (Male: p > 0.50; Female: p > 0.50) (Male: p > 0.50; Female: p > 0.50)

SGSSGSNo No

0

10

20

30

40

50

60

70

80

MEN WOMEN

Ever Had Same-Gender Sex

More Likely to Test when More Likely to Test when “Don’t Know” if Partner “Don’t Know” if Partner

diagnosed with STI in past diagnosed with STI in past YearYear(p = 0.03)(p = 0.03)

0

10

20

30

40

50

60

70

80

No Don't Know Yes

Partner Diagnosed with STI, 12 mo.

Less Likely to Test if had a Less Likely to Test if had a New Partner in Past New Partner in Past

Month !! Month !! (p = 0.01, last month vs. longer)(p = 0.01, last month vs. longer)

01020

30405060

7080

PastMonth

1-3Months

3-12Months

1+ Years

New Partner Recency

More Likely to Test if Ever More Likely to Test if Ever Had Trichomonas but not Had Trichomonas but not

GC or CT GC or CT p = 0.37 (GC), 0.57 (CT), 0.02 (TV)p = 0.37 (GC), 0.57 (CT), 0.02 (TV)

0

10

20

30

40

50

60

70

80

GC CT TV

NoYes

Any Lifetime Infection

LessLess Likely to Test if Had Likely to Test if Had GC in Past Year GC in Past Year

p = 0.01 (GC), > 0.50 (CT), 0.35 (TV)p = 0.01 (GC), > 0.50 (CT), 0.35 (TV)

0

10

20

30

40

50

60

70

80

GC CT TV

NoYes

Infection in Last Year

Impact of Missing Impact of Missing BiospecimensBiospecimensJoint Impact of:

Difference in characteristics of persons who do and do not provide biospecimens; and

Association of infection likelihood with those characteristics

Synthetic EstimatesSynthetic Estimates

2,120 biospecimens

787 imputations with full socio-demographics, sexual behaviors, STD history, and symptoms

16 imputations from socio-demographics & reduced sex and STI indicators

13 cases imputed from socio-demographics only

Estimate of Undiagnosed Estimate of Undiagnosed Trichomonas vaginalisTrichomonas vaginalis

From Biospecimens

7.6%

Biospecimens plus Imputations

7.3%

Estimate of Undiagnosed Estimate of Undiagnosed ChlamydiaChlamydia and/or and/or

TrichomonasTrichomonas From Biospecimens

10.6%

Biospecimens plus Imputations

10.2%

CONCLUSIONCONCLUSION

Feasible

Important

New Paradigm for STI Epidemiology