HIV diagnosis at CD4 count above 500 cells/mm³ and progression to below 350 cells/mm³ without antiretroviral therapy

A trial to evaluate the risks and benefits of initiation of antiretroviral therapy (ART) in patients with high CD4 count (eg, ≥500 cells/mm), in comparison with deferral (eg, to <350 cells/mm), merits consideration. Two issues for consideration in designing such a trial are the proportion of patients seen in clinics who present with high CD4 count and the time it will take for those randomized to deferring ART to reach a level where ART must be initiated. Among 13,572 patients in the UK CHIC Study presenting since 1996, 3631 (27%) had a count ≥500 cells/mm. Among 4268 ART-naive patients with at least one CD4 count in the 500 to 650 cells/mm range, the median time to <350 cells/mm (or start of ART) was 2.5 years, with a range of 2.1 to 3.1 years depending on the analysis approach. Viral load at baseline was a strong predictor of the time taken for the CD4 count to reach <350 cells/mm, with the median ranging from 0.7 years in those with viral load ≥500,000 copies/mL to 4.7 years in those with <1000 copies/mL. This provides timely background data on ART-naive patients seen in clinical practice to support design of a trial to compare immediate with deferred ART in people with high CD4 count.