SAN FRANCISCO — A sharp uptick in the prevalence and severity of Clostridium difficile colitis among hospital patients nationwide suggests that the trend extends beyond documented cases in focused regions of the United States and Canada, Dr. Rocco Ricciardi said at the annual clinical congress of the American College of Surgeons.
Analysis of national hospital data indicates “a significant change in the epidemiology of C. difficile colitis, which is likely secondary to a more virulent pathogen or less effective therapies,” Dr. Ricciardi said.
C. difficile, a gram-positive, spore-forming bacterium, was first described in 1935. Its emergence as an important cause of severe colitis can be traced to the increased use of antibiotics, which disrupt the normal flora of the colon and permit it to flourish.
Dr. Ricciardi, a colorectal surgeon on the faculty of the University of Minnesota, examined inpatient data from the Nationwide Inpatient Sample, a discharge database of approximately 7 million hospital stays per year in 1,000 hospitals in more than 30 states.
He found nearly 300,000 cases of C. difficile colitis documented in inpatient charts during the study period (1993–2003). Of those, C. difficile colitis was the primary diagnosis in 69,373 cases. The average age of the patients was 67, and 59% were females. Most patients (64%) were white.
The prevalence rose dramatically not only for primary cases of C. difficile colitis—when the condition was the major reason for hospitalization—but also for patients with a secondary diagnosis of the disease.
The findings were both statistically and clinically significant. They reflect trends seen in smaller studies from Pittsburgh and Portland, Ore., and the province of Quebec.
The case fatality rate in patients with any diagnosis of C. difficile on their charts was 7.8% in 1993, rising to 9.3% in 2003, with the sharpest increase seen from 2001 to 2003, Dr. Ricciardi said.
The C. difficile-associated mortality rate per 100,000 discharges rose from 20 to greater than 50 during the 11-year period.
The colectomy rate per 1,000 patients with a primary or secondary diagnosis of C. difficile increased from just over 1 in 1993 to 3.4 in 2003. The curve made a sharp upward turn between 2000 and 2003.
Logistic regression analysis showed that the prevalence, case/fatality rate, and colectomy rate rose even after adjustment for age, gender, race, payer type, and comorbidity.
Discussant Dr. Karen E. Deveney, professor of surgery at Oregon Health Sciences University in Portland, hailed the investigation as an important confirmation in a population study of trends seen in her city and other regions.
“I am struck by the similarity between this study and previous publications. All seem to agree that C. difficile is increasing in prevalence and severity,” she said.