Bone turnover markers in HIV-infected women on tenofovir-based antiretroviral therapy.

Background: Tenofovir disoproxil fumarate (TDF) antiretroviral therapy is associated with disruption of the bone turnover process.

Objectives: The objective of this study was to determine the association between tenofovir (TFV) plasma concentration and various bone turnover markers and compare these markers in HIV-infected women and HIV-uninfected controls.

Method: A cross-sectional sub-study included 30 HIV-infected women on TDF and 30 HIV-uninfected matched participants. Serum calcium (SrCa), serum phosphate (SrP), C-terminal telopeptide (CTx), parathyroid hormone (PTH), alkaline phosphatase (ALP), C-reactive protein (CRP), vitamin D (VitD) and bone mineral density (BMD) were measured. Plasma TFV was assayed on HPLC-MS/MS. The statistical tests applied were Mann-Whitney test, unpaired -test, analysis of covariance, regression and correlation analysis.

Results: In HIV-infected women, no correlation existed between plasma TFV concentration and CTx, PTH, ALP, SrCa, SrP, VitD or BMD ( > 0.05). After adjusting for smoking and alcohol use, ALP ( < 0.001), CTx ( = 0.027) and PTH ( = 0.050) were significantly higher in HIV-infected compared to HIV-uninfected women. Women with TFV concentration ≥ 120 ng/mL had higher PTH concentrations ( = 0.037) compared to those with ≤ 100 ng/mL. Significant correlations between SrCa and PTH and SrCa and SrP including CTx and PTH ( < 0.05) were present in HIV-uninfected women while absent in HIV-infected counterparts ( > 0.05).

Conclusion: The results indicate possible increased bone turnover at higher TFV concentrations. The normal regular bone turnover processes in HIV-infected women on TDF therapy are altered. Larger studies are warranted to confirm these results.