Background The antiretroviral combination tenofovir disoproxil, emtricitabine, cobicistat and elvitegravir (TDF/FTC/COBI/RVG) has been widely used to treat HIV infection. This regimen is related to the highest risk of kidney disease because of the ability of cobicistat to block creatinine tubular secretion, boosting tenofovir’s nephrotoxic effect because this drug is cleared using the same mechanism. Hence careful monitoring of creatinine clearance, urine glucose and protein levels, and blood phosphate levels at the start and during treatment is key.

Purpose To assess the impact of TDF/FTC/COBI/RVG on renal function in our patients, evaluating the extent to which EPAR’s monitoring needs are satisfied at the start and during treatment, and describing measures taken to resolve any incidences encountered.

Material and methods We undertook a descriptive retrospective study, involving all patients treated with TDF/FTC/COBI/EVG over 2 years. Data were collected from patients’ digital clinical and analytical histories. We registered demographic data, previous treatments with tenofovir or cobicistat, laboratory monitoring information, adjustment of monitoring to given criteria, use of other nephrotoxic drugs and measures taken if renal function decreased (if ClCr <70 mL/min then the dose was lowered; treatment was stopped if ClCr <50 mL/min).

Results 43 patients (81% men, average age 44 years) received TDF/FTC/COBI/RVG during the study period. 53% had previously been treated with tenofovir. Average ClCr was 107 mL/min (only 19% had ClCr <70 mL/min, χ=66.5 mL/min). None were monitored satisfying all of the established criteria. Only one-third of treatments from patients with decreased renal function were stopped; in one case (ClCr < 50 mL/min) additional measures were needed. Nephrotoxic drugs were found in 28% of patients’ prescriptions.

Conclusion Despite wide experience with their use, the number of cases of decreased renal function with TDF/FTC/COBI/RVG treatment has increased with time. In our study, we observed a progressive decrease in creatinine clearance, leading to hospital admission in one case. This could be because none of our patients received adequate monitoring.

No conflict of interest