How soon after HIV seroconversion is antiretroviral therapy initiated?

Objective: To estimate the time from HIV seroconversion to initiating antir etroviral therapy (ART) and whether this has changed over calendar time, an d to estimate the CD4 cell count at which ART is initiated. Design: Data from a cohort of HIV seroconverters in the UK were analysed wi th the initiation of ART as the outcome variable. Method: The association of the time from seroconversion to initiating ART w ith age, sex, exposure category, calendar time, CD4 cell count and acute in fection at diagnosis was examined using Kaplan-Meier plots and Cox proporti onal hazards models. The CD4 level at which therapy was initiated was exami ned. Results Of 1308 seroconverters, 710 (54%) had started ART by 30 September 1 998. Median interval from seroconversion to initiating ART was estimated to be 59.5 months [95% confidence interval (CI), 54.7-63.6]. Compared with 19 89-1994 (after adjusting for CD4 cell count), time to initiation of ART was significantly shorter in 1997-1998 with relative rates of initiating ART o f 1.02 (95% CI, 0.67-1.55), 1.07 (95% CI, 0.88-1.31) and 3.16 (95% CI, 2.56 -3.90) pre-1989, 1995-1996, and 1997-1998, respectively. Median CD4 cell co unt at initiation of treatment was 73 (95% CI, 30-109), 136 (95% CI, 118-16 1), 110 (95% CI, 84-140) and 221 (35% CI, 200-250) x 10(6) cells/l for the periods pre-1989, 1989-1994, 1995-1996 and 1997-1998, respectively. Of pers ons seroconverting in 1997-1998, 19.5% initiated ART within 6 months of ser oconversion compared with 8.4% and 2.0% in 1995-1996 and 1989-1994, respect ively. Conclusions: ART is being initiated closer to HIV seroconversion than in pr evious years. Whether the improvements in survival reported from recent obs ervational studies result solely from increased efficacy of the regimens or also from the timing of their initiation is difficult to determine. No cli nical trial has yet addressed the optimum timing of initiating ART in the e ra of potent therapies. (C) 1999 Lippincott Williams & Wilkins.