Rising Case Rate and Mortality Documented for C. difficile Colitis

MINNEAPOLIS, July 16 -- The frequency and severity of Clostridium difficile colitis in hospitalized patients have increased dramatically since the early 1990s, leading to greater morbidity and mortality, investigators here reported.
From 1993 through 2003 the number of reported cases of C. difficile colitis in hospitalized patients doubled, associated mortality increased by 150%, and the number of colectomies attributable to the infection increased by 50%, according to an article in the July issue of Archives of Surgery.
Frequency and mortality increased every calendar year (P<0.05 to P<0.001), reported Rocco Ricciardi, M.D., M.P.H, and colleagues, of the University of Minnesota.
Although the reasons for the rising volume of cases remain unclear, they said, the data "provide compelling evidence of the changing epidemiological features of C. difficile colitis."
C. difficile is found in the intestinal tract of 1% to 3% of healthy adults and in about 20% of patients on antibiotics. A subset of patients becomes symptomatic when native colonic flora are altered or overtaken by C. difficile. An estimated 3 million new cases of C. difficile colitis occur each year, including as many as 10% of patients hospitalized for at least two days.
Several recent reports have documented an increased incidence, and possibly increased severity, of C. difficile colitis. In an effort to clarify anecdotal and case series findings, the investigators reviewed hospital discharge data from the Agency for Healthcare Research and Quality for the period of Jan. 1, 1993 through Dec. 31, 2003.
ICD-9 codes were used to identify patients with a primary or secondary diagnosis of C. difficile colitis. The analysis revealed 299,453 cases, for which the investigators calculated total mortality, case fatality rate, and the colectomy rate associated with C. difficile colitis.
During the 11-year review period, the C. difficile colitis case rate increased from 261.0 per 100,000 to 546.0 per 100,000 (P<0.001).
Total mortality increased from 20.3 per 100,000 cases in 1993 to 50.2 per 100,000 in 2003 (P<0.001).
The case fatality rate increased from 7.8 per 100 to 9.3 per 100 (P<0.001).
The colectomy rate rose from 1.2 per 1,000 cases to 3.4 per 1,000 (P<0.001).
Selected other findings include:
There was a higher case rate in female patients but a higher mortality and colectomy rate in men.
There was a higher case rate and mortality in Medicare patients compared to all others, but a higher colectomy rate in patients with private insurance or self-pay.
Case rate and mortality increased with the number of comorbidities.
Case rate, case fatality rate, and mortality all increased with age, but the colectomy rate peaked in patients ages 60 to 69 and then decreased in older patients.
The study did not permit determination of the causes of the changing epidemiology of C. difficile colitis. The authors noted, however, that some recent epidemics have been linked to hypervirulent strains of the bacteria. Other possible explanations, they said, include increased resistance to first-line antibiotic therapy, increased use of fluoroquinolone antibiotics, and increased acuity of hospitalized patients.
In a critique that accompanied the article, Susan L. Gearhart, M.D., of Johns Hopkins, said the study emphasized the importance of judicious use of antibiotics.
"As physicians and surgeons, we cannot emphasize enough how important it is to limit the use of these antibiotics to known bacterial infections," wrote Dr. Gearhart. "In surgical prophylaxis, standardization of antibiotic type and length of perioperative coverage should be implemented in U.S. health systems. Actions such as this may help limit the prevalence of this disease."
Dr. Ricciardi, currently of the Lahey Clinic in Burlington, Mass., and the other authors had no financial disclosures. The study was supported by a grant from the University of Minnesota. Dr. Gearhart had no disclosures. Additional source: Archives of SurgerySource reference: Ricciardi R et al. "Increasing prevalence and severity of Clostridium difficile colitis in hospitalized patients in the United States." Arch Surg 2007; 142:624-631.