Survival following HIV infection in the pre-ART era in a rural Tanzanian cohort.
Isingo R, Zaba B, Marston M, Ndege M, Mngara J, Mwita W, Wringe A, Beckles D, Changalucha J, Urassa M.
AIDS 2007. vol 21 sup 6: S5-S13
Background: Survival patterns following HIV infection in African populations in the pre-ART era, form an important baseline for measuring future successes of treatment programmes. Few studies have followed sero-converters for 10 or more years to describe such patterns.
Conclusion: The survival of HIV infected persons was comparable to that reported in developed country studies prior to the introduction of HAART. Survival patterns in Kisesa are marginally more favourable than those reported in cohort studies in Uganda
Methods: The Kisesa open cohort study conducted 4 rounds of village-based HIV testing and 20 rounds of household-based demographic surveillance between 1994 and 2006. Approximate infection dates were established for individual sero-converters by allocating a date between last negative and first positive test. Person-years lived post infection were computed, allowing for left and right censoring, and Kaplan-Meier survival functions were constructed, truncating the analysis at the start of 2005 when ART first became available in the community. Weibull models were fitted to estimate median survival time, and parametric regression methods used to investigate the influence of sex and age at infection.
Results: 369 sero-converters were identified, providing 890 person-years of follow-up during which 44 deaths were observed. The Kaplan-Meier function showed 67% surviving 9 years post infection (95% CI 54% to 76%), and overall predicted median survival was 11.5 years (95% CI 10.4 to 12.5). Survival was strongly related to age at infection (Hazard ratio 1.06 for each additional year of age, CI 1.03-1.09), and weakly to sex. A strong effect of age was evident even after allowing for mortality from non-HIV related causes using cause deletion methods to estimate net mortality.