Cystatin C-based renal function changes after antiretroviral initiation: a substudy of a randomized trial.
BACKGROUND
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 1.73(2) with Modification of Diet in Renal Disease; -12.8 (-16.5, -9.0) mL/min per 1.73(2) with 2009 CKD-EPI; +8.9 (4.2, 13.7) mL/min per 1.73(2) with 2012 CKD-EPI cystatin C; and -1.2 (-5.1, 2.6) mL/min per 1.73(2) 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.
Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana.
Samir K
SK
Gupta
Center for Biostatistics in AIDS Research, Harvard School of Public Health, Boston, Massachusetts.
Douglas
D
Kitch
Center for Biostatistics in AIDS Research, Harvard School of Public Health, Boston, Massachusetts.
Camlin
C
Tierney
Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California.
Eric S
ES
Daar
Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
Paul E
PE
Sax
Gilead Sciences, Foster City, California.
Kathleen
K
Melbourne
ViiV Healthcare, Research Triangle Park, North Carolina.
Belinda
B
Ha
Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio.
Grace A
GA
McComsey
HIV-1; atazanavir; creatinine; cystatin C; nephropathy; tenofovir