title: Evidence of tendinitis provoked by fluoroquinolone treatment: a case-control study.
abstract: OBJECTIVE
  To investigate the association between the use of fluoroquinolone agents and the risk of tendinitis in a large population-based case-control study.
  
  
  METHODS
  The study was performed by linking automated health databases from the Region of Lombardia, Italy. Cases were patients aged > or =18 years who had a hospital discharge diagnosis of non-traumatic tendinitis in 2002-3. For each case, up to five controls were randomly selected among those eligible for inclusion in the study. A conditional logistic regression model was used to estimate the odds ratio of tendinitis associated with the current, recent and past use of fluoroquinolones. Odds ratios were adjusted for exposure to other antibacterials and other drugs.
  
  
  RESULTS
  22,194 cases and 104,906 controls met the inclusion criteria. Current use of fluoroquinolones significantly increased the risk of tendon disorders as a whole (odds ratio [OR] = 1.7; 95% CI 1.4, 2.0), tendon rupture (OR = 1.3; 95% CI 1.0, 1.8) and rupture of the Achilles' tendon (OR = 4.1; 95% CI 1.8, 9.6). Concomitant use of corticosteroids and fluoroquinolones increased the risk of both tendon rupture (OR = 3.1; 95% CI 1.5, 6.3) and rupture of the Achilles' tendon (OR = 43.2; 95% CI 5.5, 341.1).
  
  
  CONCLUSIONS
  Evidence that exposure to fluoroquinolones is associated with the sudden occurrence of tendinitis is supported by this large population-based study. We can estimate that a single case of rupture of the Achilles' tendon would occur for every 5958 persons treated with fluoroquinolones (95% CI 2148, 23,085). The corresponding number needed to harm is 979 (95% CI 122, 9172) for patients who concomitantly use corticosteroids and 1638 (95% CI 351, 8843) for those aged >60 years.
  
  
  CONCLUSIONS
  Clinicians should be aware of this adverse effect, and the increased risk for fluoroquinolone-associated tendinitis in elderly patients with corticosteroid use must be considered when these agents are prescribed.
authors.affiliation: Unit of Biostatistics and Epidemiology, Department of Statistics, University of Milan-Bicocca, Milan, Italy. giovanni.corrao@unimib.it
authors.forename: Giovanni
authors.initials: G
authors.lastname: Corrao
authors.forename: Antonella
authors.initials: A
authors.lastname: Zambon
authors.forename: Lorenza
authors.initials: L
authors.lastname: Bertù
authors.forename: Anna
authors.initials: A
authors.lastname: Mauri
authors.forename: Valentina
authors.initials: V
authors.lastname: Paleari
authors.forename: Camillo
authors.initials: C
authors.lastname: Rossi
authors.forename: Mauro
authors.initials: M
authors.lastname: Venegoni
mesh_terms: D000125:Achilles Tendon / Q000187:drug effects*; D016022:Case-Control Studies; D005260:Female; D024841:Fluoroquinolones / Q000009:adverse effects*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D012421:Rupture; D052256:Tendinopathy / Q000139:chemically induced* / Q000453:epidemiology
chemical_list: D024841:Fluoroquinolones