title: Achilles tendon rupture and its association with fluoroquinolone antibiotics and other potential risk factors in a managed care population.
abstract: BACKGROUND
  Case reports and observational studies have implicated fluoroquinolone antibiotic exposure as a risk factor for Achilles tendon rupture (ATR), an uncommon condition for which there are few formal studies. We sought to quantify the strength of association between exposure to fluoroquinolone antibiotics and the occurrence of ATR, accounting for other risk factors.
  
  
  METHODS
  This was a case-control study nested within a health insurer cohort. Cases of ATR were identified and confirmed using patterns of health insurance claims that were validated through sampled medical record review. Information on risk factors, including fluoroquinolone exposure, came from health insurance claims.
  
  
  RESULTS
  There were 947 cases of ATR and 18 940 controls. A dispensing of a fluoroquinolone antibiotic in the past 6 months was more common among ATR cases than controls, although not significantly so (odds ratio (OR) = 1.2; 95% confidence interval (CI) = 0.9-1.7), and exposure to a higher cumulative fluoroquinolone dose was more strongly associated (OR = 1.5, 95%CI = 1.0-2.3). Other risk factors for ATR were trauma (OR = 17.2, 95%CI = 14.0-20.2), male sex (OR = 3.0, 95%CI = 2.6-3.5), injected corticosteroid administration (OR = 2.2, 95%CI = 1.6-2.9), obesity (OR = 2.0, 95%CI = 1.2-3.1), rheumatoid arthritis (OR = 1.9, 95%CI = 1.0-3.7), skin or soft tissue infections (OR = 1.5, 95%CI = 0.9-2.3), oral corticosteroids (OR = 1.4, 95%CI = 1.0-1.8), and non-fluoroquinolone antibiotics (OR = 1.2, 95%CI = 1.1-1.5).
  
  
  CONCLUSIONS
  The elevation in ATR risk associated with fluoroquinolones was similar in magnitude to that associated with oral corticosteroids or non-fluoroquinolone antibiotics. Trauma and male sex were more strongly associated with ATR, as were obesity and injected corticosteroids.
authors.affiliation: i3 Drug Safety, Auburndale, MA, USA. jseeger@epidemiology.com
authors.forename: John D
authors.initials: JD
authors.lastname: Seeger
authors.forename: William A
authors.initials: WA
authors.lastname: West
authors.forename: Daniel
authors.initials: D
authors.lastname: Fife
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Noel
authors.forename: Larry N
authors.initials: LN
authors.lastname: Johnson
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Walker
mesh_terms: D000125:Achilles Tendon / Q000293:injuries*; D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000009:adverse effects; D000328:Adult; D016907:Adverse Drug Reaction Reporting Systems; D017677:Age Distribution; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D001172:Arthritis, Rheumatoid / Q000150:complications; D016022:Case-Control Studies; D005260:Female; D024841:Fluoroquinolones / Q000009:adverse effects*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008329:Managed Care Programs / Q000706:statistics & numerical data; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D011159:Population Surveillance; D012307:Risk Factors; D012421:Rupture; D017678:Sex Distribution; D012874:Skin Diseases, Infectious / Q000150:complications; D018461:Soft Tissue Infections / Q000150:complications; D013708:Tendon Injuries / Q000139:chemically induced / Q000453:epidemiology; D014481:United States / Q000453:epidemiology
chemical_list: D000305:Adrenal Cortex Hormones; D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones