Objective: To study the CD4 natural decrease and its determinants in sub-Saharan African HIV-infected adults.
Method: We performed a 7-year prospective cohort study, with biannual CD4 measurement. Follow-up was censored at the first severe morbidity event or at HAART initiation. Changes in CD4 values were studied by jointly modelling (a) the correlation between repeated measures through a linear mixed model and (b) the time to drop-out through a survival model.
Results: 690 patients were followed up during 1,382 person-years. Contrasting with the baseline CD4 count and percentage, which were associated with numerous variables, the slopes of both CD4 count and CD4 percentage in the absence of severe morbidity episode were only associated with the follow-up time and with the baseline body mass index (BMI). The mean annual natural decrease in CD4 count (CD4%) was estimated at -81/mm3 (-2.2%), -69/mm3 (-1.7%), and -55/mm3 (-1.2%) for patients with baseline BMI at 16 kg/m2, 20.4 kg/m2, and 25 kg/m2, respectively (p < .001). A steeper decline in the CD4 count was independently associated with a shorter event-free follow-up time.
Conclusion: These estimates of the CD4 natural decrease in sub-Saharan African patients, while they did not experience any episode of severe morbidity and before they initiate HAART, are in the bracket of those previously reported in industrialized countries. In sub-Saharan African settings with CD4 count being measured less frequently than in industrialized countries, the CD4 should be monitored more closely among adults with low BMI.