CD4-specific mortality rates among HIV-infected adults with high CD4 counts and no antiretroviral treatment in West Africa.

Background: CD4-specific rates of mortality in sub-Saharan African adults with high CD4 counts have rarely been estimated. This estimation is useful to the when to start antiretroviral treatment (ART) debate.

Methods: We pooled data from National Agency for Research on AIDS and Viral Hepatitis (ANRS)-funded research cohorts or associated partners in West Africa. All HIV-infected adults (≥18 years) with available follow-up time off ART were eligible. We used a joint model to estimate CD4 count evolution. We estimated CD4-specific rates of mortality, loss-to-follow-up (LTFU) and ART initiation by dividing the number of first event by the follow-up time off ART within each CD4 category.

Results: Between 1996 and 2009, 2588 adults (80% women) from 5 cohorts in Cote d'Ivoire and Burkina Faso were followed off ART during 6862 person-years. In the 201-350, 351-500, 501-650, and >650 cells per cubic millimeter CD4 categories, mortality rates were: 3.0, 1.5, 0.4, 0.2 per 100 person-years; LTFU rates: 6.0, 4.6, 6.1, 6.0 per 100 person-years; and ART initiation rates: 18.1, 2.7, 0.5, 0.5 per 100 person-years, respectively. All estimates varied across cohorts; mortality rates were higher when rates of LFTU and ART initiation were lower; LTFU rates were 2-40 times higher than mortality rates.

Conclusions: Among untreated West African adults with high CD4 counts, mortality and LTFU rates were substantial. Even when data are collected under research conditions, informative censoring due to ART initiation and LTFU could lead to significantly underestimate mortality figures.