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Primary Causes of Mortality in HIV Discordant Zambian Couples
Philip J Peters*1,2, I Zulu1,3, N Kancheya1,3, S Lakhi1,3, E Chomba1,3, D J Kim1,4, I Brill1,4, J Meinzen-Derr1,4, A Fraser-Bell1,5, and S Allen1,5,6
1Rwanda-Zambia HIV Res Group; 2Emory Univ Sch of Med, Atlanta, GA, US; 3Univ Teaching Hosp, Lusaka, Zambia; 4Univ of Alabama at Birmingham, US; 5Emory Rollins Sch of Publ Hlth, Atlanta, GA, US; and 6Emory AIDS Intl Training and Res Prgm, Atlanta, GA, USA
Background:
Mortality surveillance in HIV-infected people remains a vital public health
tool, however, for more than 90% of Africa’s
population there is no information on causes of adult mortality. We evaluated rates of survival and causes of
mortality in the largest prospective, community-based cohort of HIV discordant
couples in Africa.
Methods: 1528 HIV
discordant couples (3056 people) were recruited from couples’ VCT centers in Lusaka, Zambia
between January 1995 and December 2003 as part of a study on heterosexual HIV
transmission and followed at 3 month intervals.
Subjects who initiated anti-retroviral therapy (ART) were censored from
analysis. Mortality rates were compared
by HIV status, sex, CD4 count, viral load, 2005 WHO stage, and Modified Kigali
Combined stage (MKC stage– WHO-based staging system modified to incorporate
ESR, HCT, and BMI). Kaplan-Meier
survival and Cox proportional hazard methods were used to calculate time to
mortality and relative hazards. Cause of
death was ascertained by verbal autopsy, chart review, and death certificate.
Results: From
1995 to 2004, 392 people died (12.8% of cohort) over 10,378 person years (py) of follow-up.
HIV positive individuals had a median estimated survival of 8.9 years
(95% CI=8.2 – 9.1 yrs) from enrollment.
Mortality rates for HIV-infected men and women were 8.8 and 6.0 per 100 py. The 3-year
mortality rates for individuals with MKC stage 1, 2, 3, and 4 disease at enrollment were 12.7%, 11.4%, 24.7%, and 51.3%
respectively. MKC stage 4 disease (univariate HR 5.5, 95% CI=3.7-8.2) was a stronger predictor
of mortality than 2005 WHO stage 4 disease and was comparable to CD4 count
<200/mm3 and viral load >5log copies/mL. Tuberculosis and chronic gastroenteritis were
the primary causes of death among HIV positive Zambians accounting for 24% and
20% of mortality respectively.
Traditional AIDS-defining illnesses were less frequent but still
significant causes of mortality with Kaposi’s sarcoma, cryptococcal
meningitis, and candidal esophagitis
accounting for 6.3% of deaths combined.
Conclusions: HIV positive Zambians had comparable survival
times to pre-ART cohorts in high-income countries. MKC staging is a powerful, low-cost tool to
identify people at high risk for death who need urgent evaluation for ART. The burden of mortality due to tuberculosis
and chronic gastroenteritis highlights the need for parallel investment in
tuberculosis and diarrheal disease treatment as ART
scales up.
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