Clostridium difficile-associated disease and mortality among the elderly critically ill

Objective: To describe the epidemiology of and to develop a simple 30-day mortality clinical decision rule among critically ill patients >= 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. Design: Secondary analysis of a retrospective cohort study. Setting, All intensive care units at a single academic institution. Patients. A total of 278 critically ill patients with Clostridium difficile-associated disease; n = 148 aged >= 65 yrs. Interventions: None in addition to routine intensive care unit care. Measurements and Main Results. Univariate analyses were performed to compare characteristics and outcomes of the elderly vs. the younger groups, and elderly 30-day survivors with non-survivors. 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 11 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. (Crit Care Med 2009; 37:2583-2589)