Clostridium difficile-associated disease in Oregon: increasing incidence and hospital-level risk factors

The incidence of Clostridium difficile-associated disease (CDAD) appears to be increasing. Population-based estimates of disease have been limited, and analyses of hospital-level risk factors for CDAD are lacking. We sought to determine the incidence and trends of CDAD in Oregon and to identify hospital-level factors associated with increases in disease.

We analyzed hospital discharge data to calculate the incidence and to describe trends of CDAD in Oregon from 1995 through 2002. We administered questionnaires to hospital laboratory directors, infection control practitioners, and pharmacists to determine the status of laboratory, infection control, and pharmacy policies over time.

The overall incidence of CDAD in Oregon was 3.5 case patients per 10,000 residents in 2002. Incidence increased from 1.4 to 3.3 cases per 1,000 hospital discharges from 1995 to 2002. Rates of disease increased most in hospitals with licensed bed capacity of more than 250 beds and more than 5 intensive care unit beds. Few laboratories, infection control practitioners, and pharmacists were able to identify changes in specific policies over the study period.

This is the first study to determine a statewide population-based incidence of CDAD. Incidence of CDAD in Oregon has more than doubled over the past decade; larger hospitals experienced the greatest increase in disease rates. We did not identify hospital-level policies that could explain the increase. A study of patients with CDAD at the hospitals with the largest increases is underway to further identify risk factors.