title: Effect of bisphosphonate use in patients with symptomatic and radiographic knee osteoarthritis: data from the Osteoarthritis Initiative.
abstract: OBJECTIVE
  Bisphosphonates have some reported beneficial effects in treating osteoarthritis (OA). This study examined the effects of bisphosphonate use on symptoms and structural progression of knee OA in participants from the NIH Osteoarthritis Initiative cohort.
  
  
  METHODS
  People with typical OA trial entry criteria (KL2/3, minimum joint space width 2.5-5.0 mm and pain ≥4 on a numeric rating scale) were classified as bisphosphonate users (≥3 of the 5 years; n=55) or non-users (no use in the preceding 5 years or during follow-up; n=268). Annual data over 4 years were analysed using linear mixed modelling and generalised estimating equations.
  
  
  RESULTS
  Bisphosphonate compliance was 85% at year 1, reducing to 76% by year 4. Numeric rating scale pain scores were significantly reduced among bisphosphonate users at years 2 and 3 (year 3, -0.9 vs -2.2, p=0.004), though not year 4, after adjustment for baseline pain and analgesic use. Differences in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and disability scores did not reach statistical significance at any time point. There was a trend to less joint space narrowing in bisphosphonate users over time (year 4, 0.51 vs 0.29 mm; p=0.06).
  
  
  CONCLUSIONS
  Significant reduction in numeric rating scale pain was observed in the first 3 years with bisphosphonate use; diminution of effects by year 4 may reflect reduced compliance. Differences in results obtained using numeric rating scale and WOMAC may reflect different constructs measured by these tools. The beneficial trend on structural progression should be considered in terms of the sample size.
authors.affiliation: Division of Rheumatic and Musculoskeletal Disease and NIHR Leeds Musculoskeletal Biomedical Research Unit, University of Leeds, , Leeds, UK.
authors.forename: Laura L
authors.initials: LL
authors.lastname: Laslett
authors.forename: Sarah R
authors.initials: SR
authors.lastname: Kingsbury
authors.forename: Elizabeth M A
authors.initials: EM
authors.lastname: Hensor
authors.forename: Michael A
authors.initials: MA
authors.lastname: Bowes
authors.forename: Philip G
authors.initials: PG
authors.lastname: Conaghan
mesh_terms: D000368:Aged; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D004164:Diphosphonates / Q000627:therapeutic use*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000188:drug therapy*; D010147:Pain Measurement; D011859:Radiography; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates
keywords: Knee Osteoarthritis; Osteoarthritis; Outcomes research