Strategic Information and the Control of Tuberculosis

Brian Williams and Chris Dye

TB programme,Monitoring and Evaluation, WHO

Cure

Detect

Dynamical models

70%

85%

DOTS

MDGs

Ext. pul.

Smear +

Culture +

Incidence

Prevalence

Programme data

Surveys

Data Epi Programmes Policy

5%p.a.

MDR

HIV

Four questions

• Where should donors invest?

• If ‘DOTS don’t do it’ what does?

• What will ARV drugs do for TB?

• How can we monitor progress?

Estimated TB cases, 2000 Corbett et al. Archives of

Internal Medicine 2003

Estimated TB Incidence Rates, 2000

25 to 49

50 to 99

100 to 299

< 10

10 to 24

300 or more

No Estimate

per 100 000 population

The boundaries and names shown and the designations used on this map do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement.

© WHO 2001

0–1010–2425–4950–99100–299300+No data

Estimated TB incidence vs HIV prevalence

in high burden countries

0

400

800

1200

1600

0.0 0.1 0.2 0.3 0.4

HIV prevalence, adults 15-49 years

Est

imat

ed a

nn

ual

TB

in

cid

ence

(per

100

K a

du

lts,

199

9)

HIV prevalence increases by 1%TB incidence increases by 26/100k/yrEveryone had HIV, TB incidence would be 3%/yr

Four questions

• Where should donors invest?

• If DOTS don’t do it what does?

• What will ARV drugs do for TB?

• How can we monitor progress?

0

100

200

300

400

500

600

700

1980 1990 2000

TB

not

ifica

tion/

100k

0.00

0.05

0.10

0.15

HIV

pre

vale

nce

NairobiMansoer and Kutwa

0

100

200

300

400

500

600

700

1980 1990 2000

TB

not

ifica

tion/

100k

0.00

0.05

0.10

0.15

HIV

pre

vale

nce

NairobiMarum and Chebet

0

100

200

300

400

500

600

700

1980 1990 2000

TB

not

ifica

tion/

100k

0.00

0.05

0.10

0.15

HIV

pre

vale

nce

Nairobi

6 yr

DOTS plus…

• TB preventive therapy (Malawi)? • TB mass treatment (South

Africa)?• Behaviour change (Uganda)?• Condoms (Thailand)?• ART (Brazil)?• Prophylactic ART?

Impact of inteventions on TB casesT

B in

cide

nce/

100k

/yr

800

600

400

200

0

.Baseline

ARV 80%

TLTI (6 m)

TLTI (life)

ARV 100%

TB detect.

TB cure

HIV incid

Base line:CDR = 50%CR = 70%Interventions:10% increase

1980 2000 2020 2040 Year

Currie et al. AIDS 2003

PT (6 mo.)

PT (life)

Four questions

• Where should donors invest?

• If DOTS don’t do it what does?

• What will ARV drugs do for TB?

• How can we monitor progress?

0.00

0.05

0.10

0.15

1985 1990 1995 2000

Ann

ual i

ncid

ence

in A

IDS

cas

es

Pulmonary TB

Disseminated TB

Mono Dual Triple therapy

TB among AIDS patients in Brazil

www.aids.gov.br/boletim/bol_htm/boletim.htm

0.000

0.001

0.002

0.003

0.004

0 5 10 15 20

Years since HIV infection

Relative TB incidence800

700600

500

400

300200

100

0

CD4+ cell counts at start of therapy (100s/l)

1.00.90.80.70.60.50.40.30.20.10.0

800

700

600

500

400

300

200

100

0

Coveragecompliance

0.0 0.2

0.2 0.4

0.4 0.6

CD

4+ c

ell

cou

nt

at

sta

rt o

f A

RVa

Reduction in the life-time risk of TB among HIV positive people

Williams & Dye Science

Four questions

• Where should donors invest?

• If DOTS don’t do it what does?

• What will ARV drugs do for TB?

• How can we monitor progress?

Is TB incidence falling in Morocco?

0

10

20

30

40

50

60

70

1980 1985 1990 1995 2000 2005 2010 2015

Inci

den

ce r

ate/

100,

000

po

pu

lati

on

Is TB incidence falling in Morocco?

0

10

20

30

40

50

60

70

1980 1985 1990 1995 2000 2005 2010 2015

Inci

den

ce r

ate/

100,

000

po

pu

lati

on

on 1994 age-structure

on aging population

3.8% p.a.

Aging cases say that it is

35

37

39

41

43

45

1980 1985 1990 1995 2000

Ave

rag

e ag

e ca

ses

(yr)

Pulmonary TB falling fastest in children than in Morocco

0

2

4

6

8

10

12

0 20 40 60 80

Age (years)

Dec

line

in p

ulm

on

ary

TB

(%

per

cap

ita/

yr)

average rate decline 3.8%/yr

Four answers• TB investment? 22 high burden countries;

especially those where AIDS is high.

• What might work? Find and cure (better DOTS); refer TB patients for ARV; cut HIV transmission.

• What will ARVs do for TB? Reduce TB in late stage HIV; little impact on overall transmission

• Monitoring? Draw on unused local programme data, surveys, expertise and knowledge.

Stategic decision making needs...

Strategic dataCurrently national, aggregated data; local disaggregatged data; surveys; etc.

Understand the epidemiologyGood models to explain and predict; refinements for HIV

Test impactImpact of DOTS programmes; investigate context; monitoring part of treatment.