Impact of early versus deferred antiretroviral therapy on estimated glomerular filtration rate in HIV-positive individuals in the START trial.

The impact of early ART initiation (versus deferring) on kidney function has not been studied. START was a randomised comparison of immediate versus deferred ART initiation among HIV-positive persons with CD4 (cells/mm) counts >500. Serum creatinine and urine dipstick protein were measured at Months 0, 1, 4, 8 and 12, and annually thereafter. The two arms were compared for changes in eGFR (mL/min/1.73 m, calculated by CKD-EPI equation), over time using longitudinal mixed models. Of 4685 START participants, 4629 (2294 in immediate and 2335 deferred arm) were included. Median baseline CD4 and eGFR were 651 and 111.5, respectively. ART was initiated in 2271 participants (99.0%) in the immediate and 1127 (48.3%) in the deferred arm, accounting for >94% and >19% of follow-up time, respectively. Overall, 89% started ART using a tenofovir-based regimen. Over 2.1 years median follow-up, mean eGFR was 0.56 (95% CI 0.003-1.11) higher in the immediate versus deferred arm, which was more prominent after adjustment for current tenofovir or bPI use (1.85, 95% CI 1.21-2.50) and in Black participants (30.1% overall) (3.90, 95% CI 2.84-4.97) versus non-Blacks (1.05, 95% CI 0.33-1.77) (P < 0.001 for interaction). Relative risk for proteinuria in the immediate versus deferred arm was 0.74 (95% CI 0.55-1.00) (P = 0.049). In the short-term, immediate ART initiation was associated with a modestly higher eGFR and lower proteinuria risk versus deferring ART (more pronounced in Black participants). Whether this early benefit translates into a lower risk of CKD requires further follow-up.