title: Effects of renal tubular dysfunction on bone in tenofovir-exposed HIV-positive patients.
abstract: OBJECTIVE
  Tenofovir disoproxil fumarate (TDF) may cause renal tubular dysfunction (RTD) and reduce bone mineral density (BMD). We examined the relationship between RTD and BMD in TDF-exposed HIV-positive men.
  
  
  METHODS
  We analysed urinary retinol-binding protein/creatinine ratio (RBPCR) and fractional excretion of phosphate (FEPO4) to quantify RTD in a cross-sectional sample of randomly selected HIV-positive men at a single tertiary outpatient clinic. BMD at the lumbar spine and hip was measured by dual-energy X-ray absorptiometry. Multivariate logistic regression was used to analyse factors associated with RTD, and linear regression to examine the relationship between RTD and BMD.
  
  
  RESULTS
  Of 293 men (mean age 48 years, 94% White ethnicity, median TDF exposure 2.1 years), 22.5% had RBPCR-defined RTD and 12.3% had FEPO4-defined RTD. We observed a negative correlation between RBPCR and BMD at the spine (β -0.2, P = 0.002) and hip (total: β -0.1, P = 0.02; femoral neck: β -0.1, P = 0.02), but not between FePO4 and BMD. In multivariable analyses, RTD defined by more than five-fold elevations in RBPCR was associated with significantly lower BMD of the spine.
  
  
  CONCLUSIONS
  In HIV-positive patients receiving TDF-containing antiretroviral therapy, RTD was associated with lower BMD of the spine in HIV-positive men. RBPCR quantification may identify patients at increased risk of TDF-associated BMD loss.
authors.affiliation: King's College London.
authors.forename: Lisa
authors.initials: L
authors.lastname: Hamzah
authors.affiliation: Brighton and Sussex Medical School.|Brighton and Sussex University Hospitals.
authors.forename: Amanda
authors.initials: A
authors.lastname: Samarawickrama
authors.affiliation: King's College London.
authors.forename: Lucy
authors.initials: L
authors.lastname: Campbell
authors.affiliation: Brighton and Sussex Medical School.|Brighton and Sussex University Hospitals.
authors.forename: Matthew
authors.initials: M
authors.lastname: Pope
authors.affiliation: Cambridge University NHS Trust.
authors.forename: Keith
authors.initials: K
authors.lastname: Burling
authors.affiliation: Brighton and Sussex Medical School.|Brighton and Sussex University Hospitals.
authors.forename: Martin
authors.initials: M
authors.lastname: Fisher
authors.affiliation: Brighton and Sussex University Hospitals.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Gilleece
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton.
authors.forename: Karen
authors.initials: K
authors.lastname: Walker-Bone
authors.affiliation: King's College Hospital NHS Foundation Trust.
authors.forename: Frank A
authors.initials: FA
authors.lastname: Post
mesh_terms: D016263:AIDS-Associated Nephropathy / Q000139:chemically induced* / Q000150:complications*; D015502:Absorptiometry, Photon; D000328:Adult; D019380:Anti-HIV Agents / Q000009:adverse effects* / Q000627:therapeutic use; D015519:Bone Density; D003404:Creatinine / Q000652:urine; D003430:Cross-Sectional Studies; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy*; D006801:Humans; D008297:Male; D012177:Retinol-Binding Proteins / Q000652:urine; D013131:Spine / Q000473:pathology*; D000068698:Tenofovir / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D019380:Anti-HIV Agents; D012177:Retinol-Binding Proteins; D000068698:Tenofovir; D003404:Creatinine