title: Clostridium difficile-associated disease and mortality among the elderly critically ill.
abstract: OBJECTIVE
  : To describe the epidemiology of and to develop a simple 30-day mortality clinical decision rule among critically ill patients > or =65 yrs. Increasing incidence of hospitalizations with and emergence of hypervirulent epidemic strains have made Clostridium difficile-associated disease an important public health concern. Advanced age is a risk factor for development of and death from Clostridium difficile-associated disease. Intensive care unit patients with Clostridium difficile-associated disease have a high mortality, but neither the burden of nor risk factors for death among the elderly intensive care unit patients with Clostridium difficile-associated disease are well understood.
  
  
  METHODS
  : Secondary analysis of a retrospective cohort study.
  
  
  METHODS
  : All intensive care units at a single academic institution.
  
  
  METHODS
  : A total of 278 critically ill patients with Clostridium difficile-associated disease; n = 148 aged > or =65 yrs.
  
  
  METHODS
  : None in addition to routine intensive care unit care.
  
  
  RESULTS
  : Univariate analyses were performed to compare characteristics and outcomes of the elderly vs. the younger groups, and elderly 30-day survivors with nonsurvivors. Multivariable logistic regression model was developed with 30-day mortality as a dependent variable. Covariates retained in the model were assigned weighted points to develop a 30-day mortality prediction score. Area under the receiver operating characteristics curve and cross-validation analyses evaluated the score characteristics. Elderly patients were 68% more likely to experience 30-day mortality than the younger group. Absence of chronic respiratory disease (R), age 75+ yrs (A), septic shock (S), and Acute Physiology and Chronic Health Evaluation II score 20+ (A) comprised the RASA score, whose receiver operating characteristics was 0.740; 95% Confidence Interval was 0.663-0.817.
  
  
  CONCLUSIONS
  : Elderly patients represent approximately 50% of intensive care unit patients with Clostridium difficile-associated disease and have a higher 30-day mortality than younger patients. A simple prediction rule incorporating determinants of 30-day mortality easily available at the bedside may aid in optimizing treatment decisions in this growing population.
authors.affiliation: School of Public Health and Health Sciences (MDZ), University of Massachusetts, Amherst, MA, USA. Marya@evimedgroup.org
authors.forename: Marya D
authors.initials: MD
authors.lastname: Zilberberg
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Shorr
authors.forename: Scott T
authors.initials: ST
authors.lastname: Micek
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Doherty
authors.forename: Marin H
authors.initials: MH
authors.lastname: Kollef
mesh_terms: D000367:Age Factors; D000368:Aged; D002423:Cause of Death; D016360:Clostridioides difficile; D015331:Cohort Studies; D016638:Critical Illness; D004761:Enterocolitis, Pseudomembranous / Q000453:epidemiology* / Q000382:microbiology* / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors