National age group trends in Clostridium difficile infection incidence and health outcomes in United States Community Hospitals

Background: Prior studies have demonstrated an increase in Clostridium difficile infection (CDI) incidence in the United States (U.S.) in recent years, but trends among different age groups have not been evaluated. This study describes national CDI incidence by age group over a 10-year period and mortality and hospital length of stay (LOS) among patients with CDI. Methods: This was a retrospective analysis of the U. S. National Hospital Discharge Surveys from 2001 to 2010. Eligible patients with an ICD-9-CM discharge diagnosis code for CDI (008.45) were stratified by age: < 18 years (pediatrics), 18-64 years (adults), and >= 65 years (elderly adults). Data weights were used to derive national estimates. CDI incidence was calculated as CDI discharges/1000 total discharges. Mortality and LOS were compared between age groups using chi-square or Wilcoxon rank sum tests. Results: These data represent 2.3 million hospital discharges for CDI over the study period. CDI incidence was highest among elderly adults (11.6 CDI discharges/1000 total discharges), followed by adults (3.5 CDI discharges/1000 total discharges) and pediatrics (1.2 CDI discharges/1000 total discharges). The elderly also had higher rates of mortality (8.8%) compared to adults (3.1%) and pediatrics (1.4%) (p < 0.0001). In addition, median hospital LOS was highest in the elderly (8 days) compared to adults (7 days) and pediatrics (6 days) (p < 0.0001). Conclusions: CDI incidence among patients hospitalized in U. S. hospitals differed based on age group between 2001 and 2010. CDI incidence, mortality, and hospital LOS were highest in the elderly adult population.