Objective: To examine HIV disease progression in a cohort of adult patients treated with antiretroviral therapy (ART) via a clinical research network in Thailand.
Design, setting, participants and intervention: A cohort of 417 patients enrolled in a series of randomized ART trials, between 1996 and December 2002.
Main outcome measures: Progression to combined endpoint of AIDS defining illness or death according to baseline characteristics, ART used, immunological and virological responses to initial 6 months of ART.
Results: During 1677 person years of follow-up, 29 of 417 patients progressed; tuberculosis was the most common event defining progression (14 of 29 events). The rates of progression to combined endpoint or death alone were 1.7 [95% confidence interval (CI), 1.1-2.4] and 0.7 (95% CI, 0.3-1.3) per 10 person years respectively. Compared to patients with baseline CD4 cell counts > or =350 x 10/l, the adjusted hazard ratio (HR) for progression was 3.67 (95% CI, 1.31-10.27) for patients with <200 x 10 cells/l. Responses to 6 months of therapy were the strongest predictors of disease progression; compared to patients with undetectable viral load at 6 months, HR for progression was 4.95 (95% CI, 2.14-11.46) for viral load >4 log10. Compared to patients with a 6-month CD4 cell count > or =350 x 10/l, HR for progression was 5.22 (95% CI, 1.90-14.37) for patients with <200 x 10 cells/l.
Conclusions: HIV-infected patients in Thailand who had access to ART, appropriate care, CD4 cell and viral load monitoring facilities via a clinical research network had progression rates comparable to those in developed countries. In this setting, ART initiation could generally be delayed until the CD4 cell count approaches 200 x 10/l.