AIDS and Non-AIDS Morbidity and Mortality Across the Spectrum of CD4 Cell Counts in HIV-Infected Adults Before Starting Antiretroviral Therapy in Côte d’Ivoire

CD4 lymphocyte count is one of the most important determinants of human immunodeficiency virus (HIV)–related morbidity and mortality. In Western Europe, North America, and Australia, large cohort collaborations have been able to estimate the short-term CD4 cell count–specific risk of AIDS or death in untreated HIV-infected adults across a wide spectrum of CD4 cell counts [1, 2]. On the basis of these estimates, recent models suggested that CD4 cell counts of 350 cells/μL was the minimum threshold to start antiretroviral treatment (ART) but that there might be benefits to starting earlier [3, 4]. Several trials of early ART are ongoing to address the latter issue. In sub–Saharan Africa, knowledge about HIV-related morbidity and mortality in untreated patients comes from a limited number of studies. Most were cross-sectional hospital-based studies [5, 6]; very few were longitudinal [7, 8]. Of the latter, some were performed in the 1990s, when CD4 cell counts were not available, and most of the others described morbidity based on baseline and not follow-up CD4 cell counts [9–11]. Data are especially lacking in patients with high CD4 cell counts. Because of the incompleteness of existing data, it remains unclear whether HIV infection treatment guidelines should be region-specific. There is extensive evidence showing that some infectious diseases, such as tuberculosis, are more frequent in sub–Saharan Africa than in Europe or in the United States, both in the general population and in the HIV-infected population [12–17]. However, because CD4 cell count–specific rates of these diseases have not been estimated across the entire spectrum of CD4 cell counts before the ART era, the question of whether patients with similar CD4 cell counts should have different guidelines, depending on the region in which they live, has not been clearly addressed. This is particularly true when it comes to the crucial question of when to start ART. In this study, we describe the CD4 cell count–specific rates of morbidity and mortality across the full spectrum of CD4 cell counts in 2 cohorts of untreated HIV-infected adults. These cohort studies were funded by the French Agence Nationale de Recherche sur le SIDA (ANRS) in Cote d’Ivoire.