Piecewise exponential models stratified by cohort were used to estimate crude and adjusted (for sex, age, transmission risk, period of starting ART [1996–1997, 1998–1999, 2000–2001], and AIDS and human immunodeficiency virus type 1 RNA at baseline) mortality rate ratios (MRRs) by CD4 count at start of ART (0–49, 50–99, 100–199, 200–349, 350–499, ≥500 cells/μL) overall and separately according to time since start of ART. This evidence concerns the gene CD4 and AIDS.