title: Atypical Femoral Fracture in Rheumatoid Arthritis Patients Treated With Bisphosphonates: A Nested Case-Control Study.
abstract: OBJECTIVE
  To examine the clinical characteristics of atypical femoral fracture (AFF) and to determine the risk factors for and clinical outcomes of AFFs in rheumatoid arthritis (RA) patients treated with bisphosphonates (BPs).
  
  
  METHODS
  A nested case-control study was conducted using data derived from the medical records of all RA patients treated with BPs at Seoul St. Mary's Hospital, a tertiary rheumatology center, from January 1, 2008 to December 31, 2014. All of the patients with RA and had been treated with BPs for at least 1 year. Ten RA patients with AFF were identified, and each of these patients (cases) was age- and sex-matched with 4 RA patients without AFF (controls).
  
  
  RESULTS
  Five hundred fifty-two RA patients had BP exposure. Of the 10 with AFF, all were female (mean ± SD age 66.3 ± 8.7 years), and 90% of cases involved fracture of the proximal femur. The mean ± SD length of BP exposure in patients with AFF was 7.4 ± 3.2 years. Compared with controls, patients with AFF had a longer exposure to BPs and more often had a femorotibial angle of <175 degrees (both P < 0.001). There were no differences in RA duration, medications taken during the previous 6 months, and bone mineral density in the femur and lumbar spine between patients with and those without AFF. Multivariate logistic analyses identified longer BP exposure (odds ratio 2.386 [95% confidence interval 1.066-5.343]) as being associated with an increased risk of AFF.
  
  
  CONCLUSIONS
  RA patients who have a valgus deformity and are receiving long-term BP treatment are at higher risk of AFF compared with matched control patients with RA. These patients should be carefully followed up with hip radiography or dual x-ray absorptiometry.
authors.affiliation: Seoul St. Mary's Hospital and Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Koh
authors.affiliation: Seoul St. Mary's Hospital and Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Jun Pyo
authors.initials: JP
authors.lastname: Myong
authors.affiliation: Seoul St. Mary's Hospital and Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Seung Min
authors.initials: SM
authors.lastname: Jung
authors.affiliation: Seoul St. Mary's Hospital and Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Lee
authors.affiliation: Seoul St. Mary's Hospital and Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Seung-Ki
authors.initials: SK
authors.lastname: Kwok
authors.affiliation: Seoul St. Mary's Hospital and Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Sung-Hwan
authors.initials: SH
authors.lastname: Park
authors.affiliation: Seoul St. Mary's Hospital and Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Ji Hyeon
authors.initials: JH
authors.lastname: Ju
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D019386:Alendronate / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000453:epidemiology; D015519:Bone Density; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D016022:Case-Control Studies; D004164:Diphosphonates / Q000627:therapeutic use*; D005260:Female; D005264:Femoral Fractures / Q000453:epidemiology*; D005269:Femur / Q000000981:diagnostic imaging; D056304:Genu Valgum / Q000453:epidemiology*; D006801:Humans; D000077557:Ibandronic Acid; D016015:Logistic Models; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008875:Middle Aged; D015999:Multivariate Analysis; D058866:Osteoporotic Fractures / Q000517:prevention & control*; D012189:Retrospective Studies; D000068296:Risedronic Acid / Q000627:therapeutic use; D012307:Risk Factors; D013997:Time Factors
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D000068296:Risedronic Acid; D000077557:Ibandronic Acid; D019386:Alendronate