Effect of tenofovir on renal glomerular and tubular function
ABSTRACT To evaluate tenofovir-related nephropathy, we quantified calculated glomerular filtration rates (GFR) and renal tubular function in 46 tenofovir-treated patients and 25 without tenofovir. We also analysed patients who stopped tenofovir for drug-related nephrotoxicity at our clinic. Tenofovir use combined with non-nucleoside reverse transcriptase inhibitors, but not with protease inhibitors, resulted in a significant increase in calculated GFR. Tenofovir use was associated with significantly lower phosphatemia and a marginally increased fractional excretion of uric acid, but no other signs of tubulopathy.
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ABSTRACT: Tenofovir disoproxil fumarate (TDF) pre-exposure prophylaxis decreases sexual acquisition of HIV infection. We sought to evaluate the renal safety of TDF in HIV-uninfected persons. The Iniciativa Profilaxis Pre-Exposición (iPrEx) study randomly assigned 2499 HIV-seronegative men and transgender women who have sex with men (MSM) to receive oral daily TDF coformulated with emtricitabine (FTC/TDF) or placebo. Serum creatinine and phosphorus during randomized treatment and after discontinuation were measured, and creatinine clearance (CrCl) was estimated by the Cockcroft-Gault equation. Indicators of proximal renal tubulopathy (fractional excretion of phosphorus and uric acid, urine protein, and glucose) were measured in a substudy. There was a small but statistically significant decrease in CrCl from baseline in the active arm, compared to placebo, which was first observed at week 4 (mean change: -2.4 vs. -1.1 ml/min; P = 0.02), persisted through the last on-treatment visit (mean change: +0.3 vs. +1.8 ml/min; P = 0.02), and resolved after stopping pre-exposure prophylaxis (mean change: -0.1 vs. 0.0 ml/min; P = 0.83). The effect was confirmed when stratifying by drug detection. The effect of FTC/TDF on CrCl did not vary by race, age, or history of hypertension. There was no difference in serum phosphate trends between the treatment arms. In the substudy, two participants receiving placebo had indicators of tubulopathy. In HIV-seronegative MSM, randomization to FTC/TDF was associated with a very mild nonprogressive decrease in CrCl that was reversible and managed with routine serum creatinine monitoring.AIDS (London, England) 02/2014; DOI:10.1097/QAD.0000000000000156 · 6.56 Impact Factor
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ABSTRACT: Tenofovir (TDF) is associated with phosphaturia and elevated 1,25 dihydroxy vitamin D (1,25-OH(2)D). Fibroblast growth factor 23 (FGF23) causes phosphaturia and increases in response to elevated 1,25-OH(2)D. Vitamin D binding protein (VDBP) binds to 1,25-OH(2)D, decreasing its biologic activity, and is elevated in persons with higher plasma tenofovir concentrations. We compared FGF23 and VDBP before and after vitamin D3 (VITD) supplementation in youth treated with combination antiretroviral therapy (cART) containing or not containing TDF. A randomized controlled trial in HIV+ youth ages 18-25 years enrolled participants based on cART treatment with TDF (TDF, N=118) or without TDF (no-TDF, N=85) and randomized within those groups to VITD (50,000 IU every four weeks) or placebo (PL). We measured FGF23 and VDBP and calculated free 1,25-OH(2)D at baseline and week 12, and compared changes by TDF treatment and VITD randomized group. At baseline, serum FGF23 concentration showed a quadratic relationship with 1,25-OH(2)D most pronounced in the TDF group. At week 12, total and free 1,25-OH(2)D increased in the VITD but not PL groups, independent of TDF use. FGF23 increased in the TDF group receiving VITD, but there was no FGF23 change in the no-TDF group receiving VITD or the PL groups. The adjusted mean change in FGF23 from baseline to week 12 was +7.7 pg/mL in the TDF/VITD group, compared to -1.7 (no-TDF/VITD, p=0.010); -1.3 (TDF/PL, p=0.006); and +1.1 (no-TDF/PL, p=0.035). These results suggest that TDF-containing cART may alter the FGF23 response to vitamin D supplementation in HIV-infected youth.Antiviral therapy 02/2014; DOI:10.3851/IMP2755 · 3.14 Impact Factor
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ABSTRACT: Tenofovir disoproxil fumarate (TDF) has been associated with renal insufficiency. Co-administration with boosted protease inhibitors, which increases its exposure, may further increase the risk of renal insufficiency. We compared the incidence of renal events among women taking TDF co-administered with lopinavir/ritonavir (LPV/r) versus those co-administering TDF with nevirapine (NVP). Renal events were defined as a confirmed drop in creatinine clearance associated with a serum creatinine grade 2 or higher, or that leading to treatment modification. Overall, 741 HIV-infected women were enrolled into the study. Of these, 24 (3.2%) had reportable renal events (18 in LPV/r arm, 6 in NVP arm). In multivariate analysis, renal events were significantly associated with the LPV/r arm [odds ratio (OR) 3.12, 95% confidence interval (CI) 1.21, 8.05; P = 0.019], baseline HIV-1 RNA (OR 2.65, 95% CI 1.23, 5.69 per 1 log10 copies/ml higher; P = 0.013) and baseline creatinine clearance (OR 0.83, 95% CI 0.70-0.98 per 10 ml/min higher; P = 0.030). In multivariate analysis evaluating renal events requiring treatment modification, only baseline HIV-1 RNA and creatinine clearance were significantly associated (OR 4.41, 95% CI 1.65, 11.78 per 1 log10 copies/ml higher;P = 0.003 and OR 0.80, 95% CI 0.64, 0.99 per 10 ml/min higher; P = 0.040, respectively). The rates of renal events were relatively low in the two treatment arms. However, patients taking TDF co-administered with LPV/r had significantly more renal events compared to those co-administered with NVP. Furthermore, higher baseline HIV RNA and lower creatinine clearance were associated with the development of renal insufficiency requiring treatment modification.AIDS (London, England) 01/2014; 28(8). DOI:10.1097/QAD.0000000000000202 · 6.56 Impact Factor