Objective: We aimed to determine the incidence and risk factors of nephrotoxicity among Filipino human immunodeficiency virus (HIV) patients on tenofovir disoproxil fumarate (TDF).
Methods: Retrospective cohort study; we reviewed medical records of HIV adults on TDF in the University of the Philippines-Philippine General Hospital (UP-PGH) clinic from January 2004 - December 2016. Nephrotoxicity was defined as at least a 20% decline in estimated glomerular filtration rate (eGFR). Relevant demographic and laboratory data were collected. Statistical analysis was performed to compare characteristics between groups. Kaplan-Meier method was used to determine incidence rate over time, and incidence density rates of nephrotoxicity were calculated.
Results: 654 patients were included, with mean age of 29 years (18-69) and male-female ratio of 72:1. Nephrotoxicity incidence was 51.38% with a density rate of 11.05 per 10,000 person days. Kaplan Meier analysis showed probability of nephrotoxicity of 50% at 20.4 months. Cox regression modeling of covariates revealed low CD4 as a significant covariate for predicting a subsequent 20% eGFR decline.
Conclusion: TDF may contribute to a decline in GFR over time. Half of patients taking TDF developed mild nephrotoxicity by 20.5 months. Clinicians must consider the potential risk of nephrotoxicity with prolonged use especially among young patients with low CD4 counts.
HIV/AIDS, Nephrotoxicity, Tenofovir, Philippines