Gupta, Samir K.Kitch, DouglasTierney, CamlinDaar, Eric S.Sax, Paul E.Melbourne, KathleenHa, BelindaMcComsey, Grace A.2016-03-182016-03-182014-04-16Gupta, S. K., Kitch, D., Tierney, C., Daar, E. S., Sax, P. E., Melbourne, K., … for the AIDS Clinical Trials Group Study A5224s Team. (2014). Cystatin C-Based Renal Function Changes After Antiretroviral Initiation: A Substudy of a Randomized Trial. Open Forum Infectious Diseases, 1(1), ofu003. http://doi.org/10.1093/ofid/ofu0032328-8957https://hdl.handle.net/1805/8929Background.  The effects of antiretrovirals on cystatin C-based renal function estimates are unknown. Methods.  We analyzed changes in renal function using creatinine and cystatin C-based estimating equations in 269 patients in A5224s, a substudy of study A5202, in which treatment-naive patients were randomized to abacavir/lamivudine or tenofovir/emtricitabine with open-label atazanavir/ritonavir or efavirenz. Results.  Changes in renal function significantly improved (or declined less) with abacavir/lamivudine treatment compared with tenofovir/emtricitabine using the Cockcroft-Gault formula (P = .016) and 2009 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI; P = .030) and 2012 CKD-EPI cystatin C-creatinine (P = .025). Renal function changes significantly improved (or declined less) with efavirenz compared with atazanavir/ritonavir (P < .001 for all equations). Mean (95% confidence interval) renal function changes specifically for tenofovir/emtricitabine combined with atazanavir/ritonavir were −8.3 (−14.0, −2.6) mL/min with Cockcroft-Gault; −14.9 (−19.7, −10.1) mL/min per 1.732 with Modification of Diet in Renal Disease; −12.8 (−16.5, −9.0) mL/min per 1.732 with 2009 CKD-EPI; +8.9 (4.2, 13.7) mL/min per 1.732 with 2012 CKD-EPI cystatin C; and −1.2 (−5.1, 2.6) mL/min per 1.732 with 2012 CKD-EPI cystatin C-creatinine. Renal function changes for the other treatment arms were more favorable but similarly varied by estimating equation. Conclusions.  Antiretroviral-associated changes in renal function vary in magnitude and direction based on the estimating equation used.en-USAttribution-NonCommercial-NoDerivs 3.0 United StatesHIV-1atazanavircreatininecystatin CnephropathytenofovirArticle