Incidence and Risk Factors for Tenofovir-Associated Renal Function Decline Among Thai HIV-Infected Patients with Low-Body Weight

Objectives: We aimed at determining the incidence and factors for tenofovir disoproxil fumarate (TDF)- associated renal function decline among Thai HIV-infected patients. Methods: Retrospective and prospective cohort studies were conducted. We enrolled HIV-infected adults who had initiated TDF. Renal function decline was defined by a decrease of 25% in glomerular filtration rate (GFR) from the baseline. Factors associated with the renal function decline were determined. Results: A total of 405 patients with a median (interquartile range, IQR) body weight of 56.5 (50.5-65.0) kg were enrolled. All but four (99%) were antiretroviral treatment-experience patients. A median (IQR) duration of receiving TDF was 16 (8-21) months. Of these, 78 (19.3%) patients had a 25% decrease in GFR with the incidence rate of 16.2 per 100 person- years. By Kaplan-Meier survival analysis, median time to a 25% decrease in GFR was 28 [95% confidence interval (CI) 25.2-30.8] months. By multiple logistic regression, lower body weight [odds ratio (OR) 1.15 per 5 kg, 95% CI 1.00-1.33], lower body mass index (BMI) (OR 2.26 per 1 kg/m2, 95% CI 1.74-2.94), baseline GFR (OR 1.62 per 10 ml/min/1.73m2, 95% CI 1.39-1.88), protease inhibitor (OR 2.12, 95% CI 1.15-3.92), and nephrotoxic drug (OR 3.16, 95% CI 1.44-6.98) were statistically significant factors associated with a 25% decrease in GFR. Conclusions: The study revealed high incidence of TDF-associated renal function decline among patients with low-body weight and BMI. Additional risk factors were baseline GFR, receiving protease inhibitor, and nephrotoxic drugs. Close monitoring of renal function is warranted among patients with these risk factors.