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Finding the best questions for measuring AIDS mortality using verbal autopsy: A validation study in Kisesa, Tanzania and Manicaland, Zimbabwe Ben Lopman.

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Presentation on theme: "Finding the best questions for measuring AIDS mortality using verbal autopsy: A validation study in Kisesa, Tanzania and Manicaland, Zimbabwe Ben Lopman."— Presentation transcript:

1 Finding the best questions for measuring AIDS mortality using verbal autopsy: A validation study in Kisesa, Tanzania and Manicaland, Zimbabwe Ben Lopman

2 Co-authors Manicaland Cohort Jennifer Smith Godwin Chawira Simon Gregson Kisesa Cohort Adrian Cook Yusufu Kumogola Milalu Ndege Basia Zaba Mark Urassa Raphael Isingo WHO Ties Boerma

3 Objective To develop a classification system of AIDS/ non-AIDS deaths using VA data validated against HIV testing that performs consistent in –Place –Time

4 VA for AIDS mortality HIV/AIDS is the leading cause of death among young adults Hospital records and vital registration of deaths are inadequate for AIDS –bias, underreporting and stigma. Improving measurement of AIDS mortality is urgent Monitoring the success of programmes relies on accurate measurement of AIDS deaths

5 KisesaWard (Magu DSS) HIV Prev 1994/1995: 6.0% 2000/2001: 8.3% Manicaland HIV/STD Prevention Study HIV Prev 1998/2000: 23.0% 2001/2003: 20.5%

6 Mortality surveillance and VA tool The study teams identified deaths through the use of checklists of all individuals interviewed at baseline Nurse conducted interview with primary caregiver VA developed in Kisesa, used in that site until 2002. After which, a verbal autopsy questionnaire based on the INDEPTH standard was used –This questionnaire lacked a number of questions related to opportunistic infections often seen in AIDS patients A nearly identical version was used in Manicaland in both Round 1 and Round 2.

7 Gold Standard Gold standard of AIDS deaths. An individual who was –a) HIV positive at previous test –b) not accident/injury –c) not direct obstetric deaths

8 Training and testing datasets

9 AIDS deaths (gold standard)

10 Rule-based algorithm On TRAIN data Calculate LR for all signs & symptoms Based on SPECIFICITY 1.Weight loss 2. …

11

12 Specificity: 15 to 44 year

13 Sensitivity: 15 – 44 year

14 15 to 44 years (9 Signs/Symptoms) Sensitivity Specificity Manicaland KisesaManicaland Kisesa

15 45 to 59 years (9 Signs/Symptoms) Sensitivity Specificity Manicaland KisesaManicaland Kisesa

16 15 to 44 years, INDEPTH variables (5 Signs/Symptoms) Sensitivity Specificity Manicaland KisesaManicaland Kisesa

17 Using INDEPTH questions Kisesa 1994-2002

18 Using INDEPTH questions Manicaland R2

19 AIDS CSMF, Correcting for misclassification EstimateTrue Manica R176%74% Manica R288%76% Kisesa51%53%

20 Estimating HIV prevalence Estimate (95% CI) True Manica R124% (18-31)23%

21 Conclusions Developed a set of criteria using VA that consistently measures AIDS mortality Algorithm performs consistently in these settings of variable HIV prevalence Only reliable for adults under age 45 –OK in Manicaland, fewer female AIDS deaths in older adults in Kisesa Not subject to clinical biases Can estimate HIV mortality in populations lacking serosurveillance

22 INDEPTH and WHO VA Either of these widely used VA tools would face some limitations surveying AIDS mortality with the proposed criteria –Highly predictive and common Herpes zoster, oral candidiasis, abscesses/sores – Highly predictive and rare Vaginal tumors

23 Acknowledgements Funding –Health Metrics Network –Wellcome Trust –Netherlands Government People of Kisesa Ward, Tanzania and Manicaland Province, Zimbabwe –Especially Kin and Caregivers


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