Measuring mortality due to HIV-associated TB among adults in South Africa: comparing verbal autopsy, minimally-invasive autopsy, and research data
Abstract
Background
The World Health
Organization (WHO) aims to reduce tuberculosis (TB) deaths by
95% by 2035; tracking progress requires accurate measurement of
TB mortality. International Classification of Diseases (ICD)
codes do not differentiate between HIV-associated TB and HIV
more generally. Verbal autopsy (VA) is used to estimate cause of
death (CoD) patterns but has mostly been validated against a
suboptimal gold standard for HIV and TB. This study, conducted
among HIV-positive adults, aimed to estimate the accuracy of VA
in ascertaining TB and HIV CoD when compared to a reference
standard derived from a variety of clinical sources including,
in some, minimally-invasive autopsy (MIA).
Methods and findings
Decedents were
enrolled into a trial of empirical TB treatment or a cohort
exploring diagnostic algorithms for TB in South Africa. The WHO
2012 instrument was used; VA CoD were assigned using
physician-certified VA (PCVA), InterVA-4, and SmartVA-Analyze.
Reference CoD were assigned using MIA, research, and health
facility data, as available. 259 VAs were completed: 147 (57%)
decedents were female; median age was 39 (interquartile range
[IQR] 33–47) years and CD4 count 51 (IQR 22–102)
cells/μL. Compared to reference CoD that included MIA (n =
34), VA underestimated mortality due to HIV/AIDS (94% reference,
74% PCVA, 47% InterVA-4, and 41% SmartVA-Analyze;
chance-corrected concordance [CCC] 0.71, 0.42, and 0.31,
respectively) and HIV-associated TB (41% reference, 32% PCVA;
CCC 0.23). For individual decedents, all VA methods agreed
poorly with reference CoD that did not include MIA (n = 259;
overall CCC 0.14, 0.06, and 0.15 for PCVA, InterVA-4, and
SmartVA-Analyze); agreement was better at population level
(cause-specific mortality fraction accuracy 0.78, 0.61, and
0.57, for the three methods, respectively).
Conclusions
Current VA methods
underestimate mortality due to HIV-associated TB. ICD and VA
methods need modifications that allow for more specific
evaluation of HIV-related deaths and direct estimation of
mortality due to HIV-associated TB.
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Source:
PLOS ONE
