University of Colorado Hospital, Department of Pharmacy, Aurora, CO, USA.
Tenofovir disoproxil fumarate (TDF), a nucleotide reverse transcriptase inhibitor used in the treatment of human immunodeficiency virus (HIV) and hepatitis B, is renally eliminated and has been associated with renal toxicities. Dose adjustments are recommended for patients with creatinine clearance (CrCL) <50 mL/min. We retrospectively determined the frequency in which HIV clinic providers adjusted TDF doses in patients with CrCL <50 mL/min over a 2-year period and compared clinical outcomes in patients who had TDF dose adjustments based on CrCL <50 mL/min versus those who did not. Thirty-nine patients with CrCL <50 mL/min were identified. Dose-adjusted patients (N = 9) continued their TDF-based antiretroviral regimens for 21 months longer following the first CrCL < 50 mL/min (P = .0193) and had gains in CD4 cell counts over 12 months (P = .0009). There were no statistically significant differences in CrCL or percentage of patients with detectable HIV-1 RNA at 6 and 12 months following first CrCL <50 mL/min in those who did versus did not have a TDF dose adjustment. In summary, HIV providers often failed to dose-adjust TDF in patients with CrCL <50 mL/min, but dose-adjusted patients appeared to stay on their TDF-based regimens longer and have greater gains in CD4 cells. Larger, prospective studies are needed to validate these results.