title: 25 hydroxyvitamin D serum levels influence adequate response to bisphosphonate treatment in postmenopausal osteoporosis.
abstract: It remains unclear whether vitamin D sufficiency optimizes response to bisphosphonate (BP) treatment in postmenopausal osteoporosis. We evaluated the role and possible mechanisms of vitamin D in adequate response to standard BP treatment for postmenopausal osteoporosis.
  
  
  METHODS
  We included 120 postmenopausal osteoporotic women (aged 68 ± 8 years) receiving BP (alendronate or risedronate) at their annual follow-up, performing complete anamnesis, including treatment adherence, use of vitamin D supplements, and previous falls and fractures during the last year. We analyzed the evolution of bone mineral density (BMD) during this period and serum PTH and 25 hydroxyvitamin D (25(OH)D) and urinary NTx levels. Patients were classified as inadequate responders to antiosteoporotic treatment based on BMD loss>2% and/or the presence of fragility fractures during the last year.
  
  
  RESULTS
  Thirty percent of patients showed inadequate response to BP treatment, with significantly lower levels of 25(OH)D (22.4 ± 1.3 vs. 26.6 ± 0.3 ng/ml, p=0.01), a higher frequency of 25(OH)D levels<30 ng/ml (91% vs. 69%, p=0.019) and higher urinary NTx values (42.2 ± 3.9 vs. 30.9 ± 2.3 nM/mM, p=0.01). Patients with 25(OH)D>30 ng/ml had a greater significant increase in lumbar BMD than women with values <30 ng/ml (3.6% vs. 0.8%, p<0.05). The probability of inadequate response was 4-fold higher in patients with 25(OH)D<30 (OR, 4.42; 95% CI, 1.22-15.97, p=0.02).
  
  
  CONCLUSIONS
  Inadequate response to BP treatment is frequent in postmenopausal women with osteoporosis as is vitamin D insufficiency, despite vitamin D supplementation. Maintenance of 25(OH)D levels >30 ng/ml is especially indicated for adequate response to BP treatment.
authors.affiliation: Rheumatology Dpt. IDIBAPS, CIBERehd, Spain. 22848ppb@comb.cat
authors.forename: Pilar
authors.initials: P
authors.lastname: Peris
authors.forename: Angeles
authors.initials: A
authors.lastname: Martínez-Ferrer
authors.forename: Ana
authors.initials: A
authors.lastname: Monegal
authors.forename: M Jesús
authors.initials: MJ
authors.lastname: Martínez de Osaba
authors.forename: Africa
authors.initials: A
authors.lastname: Muxi
authors.forename: Nuria
authors.initials: N
authors.lastname: Guañabens
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D003430:Cross-Sectional Studies; D004164:Diphosphonates / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000097:blood* / Q000188:drug therapy*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D014807:Vitamin D; C104450:25-hydroxyvitamin D