A sharp rise in the number of adult hospitalizations and deaths attributable to Clostridium difficile infection over a 6-year period has investigators calling for increased allocation of public health resources aimed at the prevention of disease caused by the gastrointestinal pathogen.
In a population-based analysis of adult hospitalizations related to C. difficile-associated disease (CDAD) between 2000 and 2005, Dr. Marya D. Zilberberg of the University of Massachusetts School of Public Health and Health Sciences, Amherst, and colleagues determined that the incidence of adult CDAD hospitalizations rose from 5.5 cases per 10,000 population in 2000 to 11.2 per 10,000 population in 2005. Furthermore, by applying published population-based CDAD mortality estimates for 2000–2004 to the annual CDAD hospitalization volumes, they reported that the CDAD-related, age-adjusted case fatality rate rose from 1.2% in 2000 to 2.2% in 2004.
“We detected a 23% annual increase in CDAD hospitalizations in the 6-year period from 2000 through 2005,” they wrote. “Moreover, the absolute number of CDAD hospitalizations more than doubled in all age groups except the youngest, for whom they increased by 74.1% over the study period.” The rate of increase in the incidence of CDAD was steepest in those aged 85 years and older, and followed by those aged 65–84 years, those aged 45–64 years, and those aged 18–44 years (Emerg. Infect. Dis. 2008;14:929-31).
The numbers help explain the increasing mortality rates related to CDAD, the authors wrote, referring specifically to a recent report documenting a 35% per year increase in the number of CDAD deaths from 1999 through 2004 (Emerg. Infect. Dis. 2007;13:1417-9).
“By observing a 23% per year increase in the volume of hospitalizations with CDAD during 2000–2005, we demonstrate that at least half of the reported mortality increase with CDAD is due to an increase in the incidence of hospitalizations with this severe infection,” they stated, noting the increased hospitalization likely represents the effects of increased virulence of the organism and growing resistance to some antibiotics.
Data for the current analysis were obtained from the National Inpatient Sample, which is a 20% sample of U.S. community hospitals, weighted to provide national estimates. The researchers identified CDAD by ICD-9-CM code 8.45 for intestinal infection with C. difficile, and age-stratified the number of discharges per year. Using U.S. census data on numerical and demographic characteristics of the U.S. population from 2000 to 2005, they calculated age-specific hospitalization incidence rates and fitted linear models to describe the age-specific growth.
“The rapid rate of growth of CDAD-related hospitalizations and mortality is alarming, particularly in view of the aging population. If this rate of rise, along with the increase in virulence and diminished susceptibility to antimicrobial drug treatments, persists, C. difficile-associated disease will result not only in a considerable strain on the health care system but also in rising numbers of deaths.” For this reason, “research into the best preventive strategies … is a public health imperative.”