title: Subjects with osteoporosis to remain at high risk for fracture despite benefit of prior bisphosphonate treatment-a Danish case-control study.
abstract: The benefits of pharmaceutical treatment for osteoporosis may be limited for a number of patients, as they continue to experience fractures. Alternative treatments may be considered for subjects whom remain at high risk for future fractures.
  
  
  
  Previous studies have investigated the effects of good adherence to anti-osteoporosis medication. However, very few studies have described why some patients experience fractures and loss of BMD despite adherence to treatment. The aim of this study was to estimate the proportion of patients at high risk for fracture despite being compliant to bisphosphonate treatment and examine which factors influence why some osteoporotic patients remain at a high risk for fracture despite being compliant to bisphosphonate treatment.
  
  
  
  This case-control study is based on Danish national health registry data. The subjects had to have either one BMD test or a fracture prior to inclusion. "High-risk" subjects (cases) were defined as BMD t-score < =-2.5 SD, any drop in BMD from baseline or a fracture 24-36 months following inclusion.
  
  
  
  A total of 2406 subjects (66.3 % women; 33.7 % men) fulfilled the inclusion criteria, and of these, 352 (14.6 %) were identified as high risk subjects. A multiple logistical regression analysis showed that high risk subjects were more likely to have lower plasma calcium and/or vitamin D levels (OR: 2.9) and were more frequently diagnosed with hyperparathyroidism (OR: 2.6).
  
  
  
  Based on Danish national health registry data, 14.6 % patients were identified as patients remaining at high risk for fracture despite being compliant to bisphosphonate treatment. Lower plasma calcium and/or vitamin D level is the greatest predictor of high risk for fracture despite persistent bisphosphonate treatment. Secondary causes of osteoporosis should be considered and alternative treatments may be advised for subjects whom remain at high risk.
authors.affiliation: Danish Center for Healthcare Improvements, Department of Business and Management, Aalborg University, Fibigerstraede 11, DK-9220, Aalborg East, Denmark. lhan@business.aau.dk.
authors.forename: L
authors.identifier: 0000-0002-4400-2732
authors.initials: L
authors.lastname: Hansen
authors.affiliation: Danish Center for Healthcare Improvements, Department of Business and Management, Aalborg University, Fibigerstraede 11, DK-9220, Aalborg East, Denmark.
authors.forename: K D
authors.initials: KD
authors.lastname: Petersen
authors.affiliation: Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: S A
authors.initials: SA
authors.lastname: Eriksen
authors.affiliation: MSD Denmark, Ballerup, Denmark.
authors.forename: F
authors.initials: F
authors.lastname: Gerstoft
authors.affiliation: Department of Clinical Medicine, Aalborg University, Aalborg, Denmark. p-vest@post4.tele.dk.|Department of Endocrinology, Aalborg University Hospital, Aalborg, Denmark. p-vest@post4.tele.dk.
authors.forename: P
authors.initials: P
authors.lastname: Vestergaard
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000494:pharmacology / Q000627:therapeutic use*; D016022:Case-Control Studies; D003718:Denmark / Q000453:epidemiology; D004164:Diphosphonates / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D010024:Osteoporosis / Q000188:drug therapy* / Q000453:epidemiology / Q000503:physiopathology; D058866:Osteoporotic Fractures / Q000453:epidemiology / Q000503:physiopathology / Q000517:prevention & control*; D012307:Risk Factors; D012680:Sensitivity and Specificity
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates
keywords: Bone density; Calcium; Fractures; Osteoporosis; Vitamin D