SAN DIEGO, CA—Among HIV-positive patients, hepatitis C virus (HCV) coinfection, low baseline CD4 counts and other factors increase the risk of tenofovir-associated renal failure, reported authors of a retrospective cohort study presented at IDWeek 2015.

HIV-positive patients on a tenofovir-containing regimen “have a greater risk of developing renal failure if they have HCV coinfection, female gender, older age, low BMI, baseline CD4 count <200 cells/mm3 and concurrent protease inhibitor use,” reported lead study author Juhi Moon, MD, Infectious Disease, Penn State Hershey Medical Center, Hershey, Pennsylvania, and coauthors.

“These findings should help clinicians perform a risk assessment when starting or continuing HIV/HCV patients on tenofovir-based regimens,” Dr. Moon said.

Both hepatitis C virus (HCV) infection and tenofovir increase the risk of acute and chronic kidney injury in HIV-positive patients. The authors examined the roles of HCV coinfection and other risk factors in the development of renal failure among patients administered tenofovir-containing antiretroviral treatments. Using the Penn State Hershey Medical Center HIV database to identify patients with HCV and renal failure who were on a tenofovir-containing regimen between 2002 and 2015. Renal failure was defined as a 25% change in estimated glomerular filtration rate (eGFR) from baseline, with a minimal follow-up of 3 months, Dr. Moon said.

A multivariable survival analysis using the Cox model with estimates of hazard ratios (HR) and 95% confidence intervals (CI) were used to examine risk factors and time to renal failure. 

The study included a total of 709 HIV-positive patients, 141 of whom were coinfected with hepatitis. The patients had received tenofovir for a mean of 5.1 years, noted Dr. Moon. “Baseline eGFR was greater than 60mL/min/1.73m2 in 96% of patients.”  

“During the study period, 51% of HIV/HCV coinfected patients developed renal failure in a mean time of 42.8 months compared to 35% in HIV mono-infected patients in 49 months,” Dr. Moon reported. “Mean decrease in eGFR was 48mL/min/1.72m2 in coinfected patients compared to 43mL/min/1.72m2 in mono-infected patients . Presence or absence of HCV viral load did not affect renal failure prevalence in the HIV/HCV cohort (45% vs. 42%; P=0.66).”

Multivariable survival analysis indicated that HIV/HCV co-infected patients were more likely to develop renal failure than were HIV mono-infected patients (HR 1.48; 95% CI: 1.01, 2.15; P=0.042). 

Other independent risk factors for renal failure included sex (female gender: HR 1.53; 95% CI: 1.06, 2.22; P=0.02), age (HR 1.02; 95% CI: 1.00, 1.03; P=0.03), decreasing body-mass index (BMI: HR 0.97; 95% CI: 0.95, 1.00); P=0.04), concurrent protease inhibitor use (HR 1.71; 95% CI: 1.31, 2.24; P<0.0001), and baseline CD4 count <200 cells/mm3 (HR 1.41; 95% CI: 1.04, 1.90; P=0.03), the coauthors reported.