A population-based longitudinal study of Clostridium difficile infection-related hospitalization in mid-age and older adults

Background: Clostridium difficile is the principal cause of infectious diarrhea in hospitalized patients. We investigated the incidence and risk factors for hospitalization due to C. difficile infection in older adults

Methods: We linked data from a population-based prospective cohort study (the 45 and Up Study) of 266,922 adults aged ≥45 years recruited in New South Wales, Australia to hospitalization and death records for 2006-2012. We estimated the incidence of CDI hospitalization and calculated days in hospital and costs per admission. We also estimated hazard ratios (HR) for CDI hospitalization for sociodemographic and health characteristics using Cox regression with age as the underlying time variable.

Results: Over a total follow-up of 1,126,708 person-years, 187 adults had an incident CDI hospitalization; 37.4% of cases were hospitalized in the previous 2 weeks and 67.9% of cases were hospitalized in the previous 3 months. The crude incidence of CDI hospitalization was 16.6 per 100,000 person-years, with a median hospital stay of 6 days, and a median cost of AUD$ 6,102 per admission. Incidence increased with age and year of follow up, with a 3-fold increase for 2009-2012. After adjustment, CDI hospitalization rates were significantly lower in males than females (adjusted HR 0.6, 95%CI 0.4-0.7) and increased with decreasing health (aHR for poor vs excellent health: 5.7, 95%CI 2.1-15.5).

Conclusion: CDI hospitalization rates increased significantly over 2009-2012. Approximately one third of patients with CDI hospitalization had no recent hospital exposure, indicating probable acquisition in the community. There is a need to better understand the increasing incidence of CDI hospitalization among women.