title: Mortality after infection with methicillin-resistant Staphylococcus aureus (MRSA) diagnosed in the community.
abstract: BACKGROUND
  Outbreak reports suggest that community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections can be life-threatening. We conducted a population based cohort study to assess the magnitude of mortality associated with MRSA infections diagnosed in the community.
  
  
  METHODS
  We used the United Kingdom's General Practice Research Database (GPRD) to form a cohort of all patients with MRSA diagnosed in the community from 2001 through 2004 and up to ten patients without an MRSA diagnosis. The latter were frequency-matched with the MRSA patients on age, GPRD practice and diagnosis date. All patients were older than 18 years, had no hospitalization in the 2 years prior to cohort entry and medical history information of at least 2 years prior to cohort entry. The cohort was followed up for 1 year and all deaths and hospitalizations were identified. Hazard ratios of all-cause mortality were estimated using the Cox proportional hazards model adjusted for patient characteristics.
  
  
  RESULTS
  The cohort included 1439 patients diagnosed with MRSA and 14,090 patients with no MRSA diagnosis. Mean age at cohort entry was 70 years in both groups, while co-morbid conditions were more prevalent in the patients with MRSA. Within 1 year, 21.8% of MRSA patients died as compared with 5.0% of non-MRSA patients. The risk of death was increased in patients diagnosed with MRSA in the community (adjusted hazard ratio 4.1; 95% confidence interval: 3.5-4.7).
  
  
  CONCLUSIONS
  MRSA infections diagnosed in the community are associated with significant mortality in the year after diagnosis.
authors.affiliation: Division of Clinical Epidemiology, McGill University Health Center, Royal Victoria Hospital, 687 Pine Avenue West, Ross 4,29, Montreal, H3A 1A1, Canada. joseph.delaney@mail.mcgill.ca
authors.forename: J A 'Chris'
authors.initials: JA
authors.lastname: Delaney
authors.forename: Verena
authors.initials: V
authors.lastname: Schneider-Lindner
authors.forename: Paul
authors.initials: P
authors.lastname: Brassard
authors.forename: Samy
authors.initials: S
authors.lastname: Suissa
mesh_terms: D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000382:microbiology / Q000401:mortality*; D006801:Humans; D016106:Methicillin Resistance; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000382:microbiology / Q000401:mortality*; D013211:Staphylococcus aureus / Q000302:isolation & purification*