Mortality and its predictors among antiretroviral therapy naive HIV-infected individuals with CD4 cell count >= 350 cells/mm(3) compared to the general population: data from a population-based prospective HIV cohort in Uganda

Background: Evidence exists that even at high CD4 counts, mortality among HIV-infected antiretroviral therapy (ART) naive individuals is higher than that in the general population. However, many developing countries still initiate ART at CD4 <= 350 cells/mm(3). Objective: To compare mortality among HIV-infected ART naive individuals with CD4 counts >= 350 cells/mm(3) with mortality in the general Ugandan population and to investigate risk factors for death. Design: Population-based prospective HIV cohort. Methods: The study population consisted of HIV-infected people in rural southwest Uganda. Patients were reviewed at the study clinic every 3 months. CD4 cell count was measured every 6 months. Rate ratios were estimated using Poisson regression. Indirect methods were used to calculate standardised mortality ratios (SMRs). Results: A total of 374 participants with CD4 >= 350 cells/mm(3) were followed for 1,328 person-years (PY) over which 27 deaths occurred. Mortality rates (MRs) (per 1,000 PY) were 20.34 (95% CI: 13.95-29.66) among all participants and 16.43 (10.48-25.75) among participants aged 15-49 years. Mortality was higher in periods during which participants had CD4 350-499 cells/mm(3) than during periods of CD4 >= 500 cells/mm(3) although the difference was not statistically significant [adjusted rate ratio (aRR) = 1.52; 95% CI: 0.71-3.25]. Compared to the general Ugandan population aged 15-49 years, MRs were 123% higher among participants with CD4 >= 500 cells/mm(3) (SMR: 223%, 95% CI: 127-393%) and 146% higher among participants with CD4 350-499 cells/mm(3) (246%, 117%-516). After adjusting for current age, mortality was associated with increasing WHO clinical stage (aRR comparing stage 3 or 4 and stage 1: 10.18, 95% CI: 3.82-27.15) and decreasing body mass index (BMI) (aRR comparing categories <= 17.4 Kg/m(2) and >= 18.5 Kg/m(2): 6.11, 2.30-16.20). Conclusion: HIV-infected ART naive individuals with CD4 count >= 350 cells/mm(3) had a higher mortality than the general population. After adjusting for age, the main predictors of mortality were WHO clinical stage and BMI.