title: Effectiveness of oral bisphosphonates for primary prevention of osteoporotic fractures: evidence from the AIFA-BEST observational study.
abstract: OBJECTIVE
  Osteoporosis is a chronic disease of the bone, whose incidence increases progressively with aging. The main consequences of osteoporosis are fragility fractures, which have considerable medical, social, and economic implications. Adequate treatment of osteoporosis must be considered as a compelling public health intervention. Bisphosphonates (BPs) represent the most significant advance in this field in the past decade, and they are widely used in the treatment of osteoporosis. However, evidence for their effectiveness is limited to secondary prevention, whereas their effect in primary prevention is uncertain and needs further investigation.
  
  
  METHODS
  Using administrative data collected in the "Biphosphonates Efficacy-Safety Tradeoff" (BEST) study, a nested case-control study was conducted by including 56,058 participants, aged 55 years who were started on oral BPs from 2003 to 2005. Cases were the 1,710 participants who were hospitalized for osteoporotic fractures until 2007. Up to 20 controls were randomly selected for each case. Conditional logistic regression model was used to estimate odds ratio of fracture associated with categories of treatment duration.
  
  
  RESULTS
  Compared with participants assuming BPs for less than 1 year, those who remained on therapy for at least 2 years had a 21% (95% confidence interval (CI) 7 to 33%) fracture risk reduction.
  
  
  CONCLUSIONS
  This study provides evidence that BPs, dispensed for primary prevention of osteoporotic fractures, are associated with a reduced risk of osteoporotic fractures after at least 2 years of treatment.
authors.affiliation: Unit of Biostatistics and Epidemiology, Department of Statistics and Quantitative Methods, University of Milano-Bicocca, Milan, Italy.
authors.forename: Arianna
authors.initials: A
authors.lastname: Ghirardi
authors.forename: Mauro
authors.initials: M
authors.lastname: Di Bari
authors.forename: Antonella
authors.initials: A
authors.lastname: Zambon
authors.forename: Lorenza
authors.initials: L
authors.lastname: Scotti
authors.forename: Gianluca
authors.initials: G
authors.lastname: Della Vedova
authors.forename: Francesco
authors.initials: F
authors.lastname: Lapi
authors.forename: Francesco
authors.initials: F
authors.lastname: Cipriani
authors.forename: Achille P
authors.initials: AP
authors.lastname: Caputi
authors.forename: Alberto
authors.initials: A
authors.lastname: Vaccheri
authors.forename: Dario
authors.initials: D
authors.lastname: Gregori
authors.forename: Rosaria
authors.initials: R
authors.lastname: Gesuita
authors.forename: Annarita
authors.initials: A
authors.lastname: Vestri
authors.forename: Tommaso
authors.initials: T
authors.lastname: Staniscia
authors.forename: Giampiero
authors.initials: G
authors.lastname: Mazzaglia
authors.forename: Giovanni
authors.initials: G
authors.lastname: Corrao
mesh_terms: D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D016022:Case-Control Studies; D004164:Diphosphonates / Q000627:therapeutic use*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008875:Middle Aged; D016017:Odds Ratio; D058866:Osteoporotic Fractures / Q000453:epidemiology / Q000517:prevention & control*; D011322:Primary Prevention; D016896:Treatment Outcome
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates