Impact of emtricitabine/tenofovir (FTC/TDF) on renal function in antiretroviral-naïve patients ≥50 years - TRIP study

Purpose: In the last decade the prevalence of HIV-infected patients ≥50 years of age has increased. FTC/TDF is nowadays one of the cornerstones of cART in naive patients, generally considered safe and well tolerated; nevertheless there is a continuous debate about the renal safety of TDF, due to the report of cases linking this treatment with renal failure and tubular dysfunction. In addition, there is a well-recognized age-related decline in renal function. Our aim was to describe the impact of cART regimen (FTC/TDF vs. others) on renal function of subjects who start cART at ≥50 years old. Methods: National, retrospective cohort analysis of HIV-infected patients >50 y at the time they began the first cART (Jan 1, 2006 - Dec 31, 2009). Patients were selected in a proportion 2:1 to FTC/TDF versus other NRTI regimens (no TDF). For this analysis we excluded subjects taking potentially nephrotoxic drugs at baseline. We compared the impact of FTC/TDF vs. no-TDF regimens (main groups) on renal function by means of the changes, during the first 12 months of treatment, in glomerular filtration rate estimated by the CKD-EPI formula, and by the analysis of time to renal deterioration during the complete follow up (defined as progression to an EPI-CKD value 60). We also compared these outcomes among FTC/TDF users, according to the third agent: PI vs. NNRTI, and lopinavir/r vs. efavirenz. Results: We included 125 patients, median age: 54.8 y, 82% males, median CD4 count 235 cells/μl, median viral load 4.7 log, follow up: median 19 months, max: 66 months. Of them, 82 started with FTC/TDF and 43 with other NRTIs (no TDF). During the follow-up 13/125 patients taking FTC/TDF (11%) presented with renal deterioration. The Cox regression model including age, sex, transmission category, baseline CD4 count and viral load, FTC/TDF use, PI/NNRTI use, and LPVr/EFV use showed a hazard ratio for renal deterioration of 4.13 (95% CI 0.92, 18.5) for LPV/r users. The table shows the evolution of glomerular filtration rate, and proportion and risk of renal deterioration. Conclusion: In subjects starting cART after 50 years of age, we have not found significant changes in glomerular filtration rate associated with the use of FTC/TDF-based regimens. Overall, the risk of renal deterioration was 4.1 times higher for LPV/r users (almost statistically significant). Among FTC/TDF users, this risk was 8 times higher for LPV/r as compared to EFV. (Published: 11 November 2012) Citation: Abstracts of the Eleventh International Congress on Drug Therapy in HIV Infection Blanco J et al. Journal of the International AIDS Society 2012, 15 (Suppl 4):18312 http://www.jiasociety.org/index.php/jias/article/view/18312 | http://dx.doi.org/10.7448/IAS.15.6.18312