title: Effect of ribotype on all-cause mortality following Clostridium difficile infection.
abstract: BACKGROUND
  Clostridium difficile infection (CDI) is significantly associated with subsequent all-cause mortality. Although a number of studies have investigated mortality associated with CDI, few have compared all-cause mortality between ribotypes.
  
  
  OBJECTIVE
  We aimed to estimate all-cause mortality following CDI and to investigate the relationship between mortality, ribotype and other available variables.
  
  
  METHODS
  We undertook a retrospective cohort study. All patients with toxin-positive CDI in North East England between July 2009 and June 2011 were matched to death registration data. Differences in all-cause 30-day case fatality were explored using Poisson regression with robust error variances. For survival analysis, an accelerated failure time model with generalized gamma distribution was chosen.
  
  
  RESULTS
  In total, 1426 patients were included. All-cause case fatality was 10.2%, 16.4%, 25.7% and 38.1% at 7, 14, 30 and 90 days respectively. In multivariate analysis, ribotype 027 (risk ratio: 1.34; 95% confidence interval: 1.02-1.75) and ribotype 015 (0.46; 0.26-0.82) were significantly associated with higher and lower all-cause 30-day case fatality rates, respectively. In survival analysis, only ribotype 015 had significantly lower predicted mortality (P = 0.008). Patients whose infection was hospital-acquired had significantly higher predicted mortality (P < 0.001).
  
  
  CONCLUSIONS
  This is the first population-based study of comparative mortality between multiple ribotypes. Our study identified a high rate of all-cause mortality following CDI. We found evidence of variability in mortality between ribotypes in this cohort with mortality significantly higher for ribotype 027 at 30 days following diagnosis and significantly lower for ribotype 015.
authors.affiliation: Regional Epidemiology Unit, Health Protection Agency North East, UK. thomas.inns@hpa.org.uk
authors.forename: T
authors.initials: T
authors.lastname: Inns
authors.forename: R
authors.initials: R
authors.lastname: Gorton
authors.forename: A
authors.initials: A
authors.lastname: Berrington
authors.forename: A
authors.initials: A
authors.lastname: Sails
authors.forename: T
authors.initials: T
authors.lastname: Lamagni
authors.forename: J
authors.initials: J
authors.lastname: Collins
authors.forename: J
authors.initials: J
authors.lastname: Perry
authors.forename: K
authors.initials: K
authors.lastname: Hill
authors.forename: J
authors.initials: J
authors.lastname: Magee
authors.forename: K
authors.initials: K
authors.lastname: Gould
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016360:Clostridioides difficile / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D003015:Clostridium Infections / Q000382:microbiology* / Q000401:mortality*; D015331:Cohort Studies; D004739:England; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D021521:Ribotyping; D016019:Survival Analysis