Results from a Multicenter Cohort Study

Background. Relatively few data are available on the association between the use of specific antiretroviral drugs and the rate of viral rebound in those attaining a viral load (VL)!50 copies/mL while receiving highly active antiretroviral therapy (HAART). Methods. Patients achieving a VL!50 copies/mL for the first time while receiving HAART were followed until viral rebound (2 consecutive VLs 1500 copies/mL). Pre-HAART antiretroviral-naive patients were analyzed separately from those with nucleoside reverse transcriptase inhibitor (NRTI) experience. Results. Of 3565 suppressed antiretroviral-naive patients, 381 experienced viral rebound (rate, 6.26 events/ 100 person-years of follow-up [pyrs] [95 % confidence interval {CI}, 5.63–6.89 events/100 pyrs]). For those receiving efavirenz, the rate was 4.08 (95 % CI, 3.16–5.01) events/pyrs. Compared with this, the rebound rate for those receiving indinavir was 1.52 times higher (rate ratio [RR], 1.52 [95 % CI, 0.82–2.84]). RRs (95 % CIs) for othe