Abstract : Background: Renal toxicity is a common side effect during tenofovir (TDF)-use in HIV-infected, but not necessarily HBV-infected, patients. Nevertheless, little is known regarding TDF-use on renal impairment during HIV–HBV coinfection. We aimed to evaluate the progression and determinants of renal impairment in coinfected patients undergoing TDF.
Methods: A total of 175 coinfected patients initiating TDF-containing antiretroviral therapy were prospectively followed. Estimated glomerular filtration rates (eGFR) were calculated at baseline and every 6–12 months. Determinants of eGRF change from baseline (ΔeGFR) were evaluated using mixed-effect linear regression and progression towards renal impairment using proportional-hazards regression.
Results: At baseline, average eGFR was 96.7 ml/min per 1.73m2 (95% CI 93.8, 99.6). During a median 58.3 months (IQR 33.7–92.1) of treatment, eGFR decreased a monthly average of -0.14 ml/min per 1.73m2 (95% CI -0.16, -0.12). Significantly faster ΔeGFR was associated with baseline eGFR>90 (P=0.002), male gender (P=0.04), previous AIDS-defining illness at baseline (P=0.03), baseline liver cirrhosis (P=0.03) and concomitant protease inhibitor use (P=0.005). Between respective baseline and end of follow-up visits, the proportion of patients with renal impairment increased: normal function, 65.7% to 53.1%; mild impairment, 32.6% to 40.0%; moderate impairment, 1.7% to 6.9%. Higher age (P=0.01) and previous AIDS-defining illness (P=0.02) at baseline were independent risk-factors for developing impairment, while undetectable HBV DNA on-treatment was protective (P=0.006). Five (2.9%) patients permanently discontinued TDF after a renal event.
Conclusions: Severe HIV-related and HBV-related morbidity negatively affects renal function in coinfected patients undergoing long-term TDF. Although most patients only developed mild/moderate impairment, close renal monitoring is warranted for this particular population.