title: Risk of septic arthritis in patients with rheumatoid arthritis and the effect of anti-TNF therapy: results from the British Society for Rheumatology Biologics Register.
abstract: OBJECTIVE
  To evaluate the risk of septic arthritis (SA) in patients with rheumatoid arthritis (RA) treated with anti-tumour necrosis factor (TNF) therapy.
  
  
  METHODS
  Using data from the British Society for Rheumatology Biologics Register, a prospective observational study, the authors compared the risk of SA between 11 881 anti-TNF-treated and 3673 non-biological disease-modifying antirheumatic drug (nbDMARD)-treated patients.
  
  
  RESULTS
  199 patients had at least one episode of SA (anti-TNF: 179, nbDMARD: 20). Incidence rates were: anti-TNF 4.2/1000 patient years (pyrs) follow-up (95% CI 3.6 to 4.8), nbDMARD 1.8/1000 pyrs (95% CI 1.1 to 2.7). The adjusted HR for SA in the anti-TNF cohort was 2.3 (95% CI 1.2 to 4.4). The risk did not differ significantly between the three agents: adalimumab, etanercept and infliximab. The risk was highest in the early months of therapy. The patterns of reported organisms differed in the anti-TNF cohort. Prior joint replacement surgery was a risk factor for SA in all patients. The rate of postoperative joint infection (within 90 days of surgery) was 0.7%. This risk was not significantly influenced by anti-TNF therapy.
  
  
  CONCLUSIONS
  Anti-TNF therapy use in RA is associated with a doubling in the risk of SA. Physicians and surgeons assessing the RA patient should be aware of this potentially life-threatening complication.
authors.affiliation: Arthritis Research UK Epidemiology Unit, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK.
authors.forename: J B
authors.initials: JB
authors.lastname: Galloway
authors.forename: K L
authors.initials: KL
authors.lastname: Hyrich
authors.forename: L K
authors.initials: LK
authors.lastname: Mercer
authors.forename: W G
authors.initials: WG
authors.lastname: Dixon
authors.forename: A P
authors.initials: AP
authors.lastname: Ustianowski
authors.forename: M
authors.initials: M
authors.lastname: Helbert
authors.forename: K D
authors.initials: KD
authors.lastname: Watson
authors.forename: M
authors.initials: M
authors.lastname: Lunt
authors.forename: D P M
authors.initials: DP
authors.lastname: Symmons
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000009:adverse effects*; D001170:Arthritis, Infectious / Q000150:complications* / Q000453:epidemiology; D001172:Arthritis, Rheumatoid / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects; D007595:Joint Prosthesis / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009894:Opportunistic Infections / Q000150:complications* / Q000453:epidemiology; D016459:Prosthesis-Related Infections / Q000150:complications / Q000453:epidemiology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D018501:Antirheumatic Agents; D007166:Immunosuppressive Agents; D014409:Tumor Necrosis Factor-alpha