WHO and IHME estimates of TB disease burden: Comparison ......WHO and IHME estimates of TB disease burden: Comparison of methods and results Global Task Force on TB Impact Measurement

WHO and IHME estimates of TB disease burden:

Comparison of methods and results

Global Task Force on TB Impact Measurement

3rd meeting of the TB estimates subgroup

Glion-sur-Montreux, 31 March- 2nd April 2015

Laura Anderson

Philippe Glaziou

GLOBAL TB PROGRAMME

Outline

• Comparison of methods: Key points only

• What can be compared?

• Comparison of results: Key points only

• Additional analysis to help understand results

Topic WHO IHME

Main data sources Notifications (All countries)

VR data (2170 country-years)

Prevalence survey data (national)

(15 countries)

Tuberculin surveys (3 countries)

Inventory study results (n=5)

10 predictive covariates (e.g. GDP

per capita, u5MR, HIV prevalence)

Notifications (All countries)

VR (2731 country-years)

VA data (166 site-years)

Prevalence survey data

(national and sub-national)

(24 countries)

11 predictive covariates (e.g.

smoking prevalence, diabetes,

indoor air pollution, alcohol

and health system access)

Population estimates

and mortality envelope

UN Population Division

57 million deaths in 2013

IHME population estimates

53 million deaths in 2010

Comparison of WHO and IHME methods for all

indicators

Comparison of WHO and IHME methods for all

indicators

Variable WHO IHME

Overall analytical

/model

framework

Internally consistent models

combining different data

sources

Uncertainty documented

No age standardisation

Bayesian model (Dismod MR-2.0)

WHO TB burden estimates of case

detection rate are used for some

of the priors

Uncertainty documented

Standardised for age

Country

consultations?

Burden estimates shared with

all countries for review each

year plus other in-depth

reviews

Reproducibility by

others

Not reproducible: some raw

data not published, computer

code not published

Not reproducible: raw country

data and computer code not

publicly available

What could we compare?

• 153 countries and territories for incidence and 187 for prevalence and

mortality, 98% global population

• Rates only (not absolute numbers)

• TB incidence and mortality (HIV negative ) 1990-2013

• TB incidence (HIV positive and negative), 2013

• TB prevalence (HIV negative and positive), 1990 -2013

• Age standardised IHME with non-age standardised WHO

Incidence and prevalence: Country-specific estimates were provided for 1990, 1995, 2000, 2005,

2010 and 2013. Linear interpolation was used to complete time-series.

Key Results

WHO (blue) and IHME (red) estimates of global TB incidence,

mortality and prevalence rates, 1990−2013

WHO (blue) and IHME (red) estimates of HIV-negative TB

incidence rates by WHO region, 1990−2013

WHO (blue) and IHME (red) estimates of HIV-negative TB

incidence rates, four countries with robust TB surveillance

systems, 1990-2013

WHO and IHME estimates of HIV-negative TB incidence rates in

2013*

AFR AMR EMR

EUR SEA WPR

0

250

500

750

0

50

100

150

0

100

200

300

0

50

100

150

100

200

300

0

100

200

0 100 200 300 400 0 50 100 150 0 200 400 600

0 50 100 150 100 200 300 400 0 100 200 300 400Incidence rate (WHO)

Inc

ide

nc

e r

ate

(IH

ME

)

*22 high TB burden countries shown in red

China

WHO (blue) and IHME (red) estimates of HIV-negative TB

mortality rates by WHO region, 1990−2013

Mortality reduction 1990-2013

Reasonable agreement in regional aggregates

The red segments indicate weighted means for each WHO region (using population weights)

------------------------------------------ ------------------------------------------ ------------------------- ------------------------ --------------------- ---------------------

---------------------------------------------- ---------------------------------------------- --------- --------- -------------- -------------

AFR AMR EMR

EUR SEA WPR

-100

-50

0

50

100

150

-100

-50

0

50

100

150

WHO IHME WHO IHME WHO IHME

Mo

rta

lity

re

du

cti

on

(%

)

WHO (blue) and IHME (red) estimates of HIV-negative TB

mortality rates, four countries with robust TB surveillance

systems, 1990-2013

AFR AMR EMR

EUR SEA WPR

1

10

100

1

10

1

100

0.1

1.0

10.0

10

100

1

10

100

1 10 100 0.1 1.0 10.0 1e-41 1e-29 1e-17 1e-05

0.1 1.0 10.0 10 100 1 100Mortality (WHO)

Mo

rta

lity

(IH

ME

)WHO and IHME estimates of HIV-negative TB mortality rates by

WHO region, 2013 (log scale)

*22 high TB burden countries shown in red

China

WHO (blue) and IHME (red) estimates of TB prevalence rates by

WHO region, 1990−2013

Prevalence reduction by 2013 compared with the level of 1990

The red segments indicate weighted means for each WHO region (using population weights)

------------------------------------------ ------------------------------------------ ------------------------- ------------------------ --------------------- ---------------------

---------------------------------------------- ---------------------------------------------- --------- --------- -------------- -------------

AFR AMR EMR

EUR SEA WPR

-100

0

100

200

-100

0

100

200

WHO IHME WHO IHME WHO IHME

Pre

va

len

ce

re

du

cti

on

(%

)

Additional analysis to understand

differences between WHO and IHME

TB burden estimates

Different approaches to adjustment of prevalence survey data?

RWA 2012

NGA 2012

GMB 2012

PAK 2011

KHM 2011

LAO 2011

ETH 2011

CHN 2010

KHM 2002

MMR 2009

PHL 2007

VNM 2007

CHN 1990

CHN 2000

PHL 1997

100 200 300 400 500 1000 1500 2000

Prevalence per 100,000

AFR AMR EMR

EUR SEA WPR

0.00

0.25

0.50

0.75

1.00

1.25

0.1

0.2

0.3

0.4

0.0

0.2

0.4

0.6

0.0

0.1

0.2

0.3

0.4

0.1

0.2

0.3

0.4

0.1

0.2

0.3

0.4

0.5

0.1 0.2 0.3 0.4 0.1 0.2 0.3 0.4 0.5 0.1 0.2 0.3 0.4

0.0 0.1 0.2 0.3 0.4 0.1 0.2 0.3 0.4 0.0 0.1 0.2 0.3 0.4

CFR (WHO)

CF

R (

IHM

E)

Differences in relationship between incidence and mortality

(CFR)

AFR AMR EMR

EUR SEA WPR

25

50

75

100

0

30

60

90

120

40

60

80

100

120

140

25

50

75

100

75

100

125

100

200

25 50 75 100 40 60 80 100 60 80 100

70 80 90 100 40 60 80 100 40 60 80 100

CDR (WHO)

CD

R (

IHM

E)

Differences in relationship between notifications and incidence

(CDR)

Extra slides

WHO (blue) and IHME (red) estimates of HIV-negative TB

incidence rates, 22 high TB burden countries, 1990−2013

WHO (blue) and IHME (red) estimates of HIV-negative TB

mortality rates, 22 high TB burden countries, 1990−2013

WHO (blue) and IHME (red) estimates of TB prevalence rates,

22 high TB burden countries, 1990−2013

AFR AMR EMR

EUR SEA WPR

100

1000

10

100

100

10

100

10

100

100 1000 1 100 10 1000

1 10 100 100 1000 10 100 1000Prevalence (WHO)

Pre

va

len

ce

(IH

ME

)

WHO and IHME estimates of TB prevalence by WHO region,

2013 (log scale)

*22 high TB burden countries shown in red

AFR AMR

EMR EUR

SEA WPR

-0.10

-0.05

0.00

0.05

0.10

-0.10

-0.05

0.00

0.05

0.10

-0.10

-0.05

0.00

0.05

0.10

-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3

dI/dt (WHO)

dI/

dt

(IH

ME

)

1990

1995

2000

2005

2010

year

WHO and IHME estimates of rates of change in HIV-negative TB

incidence by WHO region, 1990-2013