Zaba B, Marston M, Crampin A, Isingo R, Biraro S, Barninghaus T, Lopman B, Lutalo T and Todd J.
AIDS 2007vol 21 sup 6: S87-S96
Objectives: Describe age-specific mortality patterns of HIV-infected adults in African communities before introduction of HAART.
Methods: Mortality data (deaths and person-years observed) for HIV positive subjects aged 15-65 from six African community studies in five different countries were pooled, combining information from 1,793 sero-converters and 8,534 HIV positive when first tested. Age-specific mortality hazards were modelled using parametric regression based on the Weibull distribution, to investigate effects of sex, and site-specific measures of mean age at incidence, crude mortality rate of uninfected, and measures of epidemic maturity.
Results: The combined studies yielded a total of 31,777 person-years of observation for HIV positive subjects, during which time 2,602 deaths were recorded. Mortality rates rose almost linearly with age, from below 50 per thousand at ages <20, to 150 per thousand at ages 50+. There was no significant difference between men and women in level or age pattern of mortality. Weibull regression analysis suggested inter-site variation could be explained by HIV prevalence trend, and by the ratio of HIV proportional mortality to current HIV prevalence. A model representation was constructed with a common age pattern of mortality, but allowing the level to be adjusted by specifying HIV prevalence indicators.
Conclusions: The linear age trend of mortality in HIV infected populations was satisfactorily represented by a Weibull function, providing a parametric model adaptable for representing different levels of HIV-related mortality. This model might be simpler to use in demographic projections of HIV affected populations than models based on survival post infection.