C. difficile onset increases in communities, decreases in hospitals

Community-acquired Clostridium difficile rates increased in the United States between 2010 and 2013, according to data presented at the 2016 Society of Hospital Medicine annual meeting. Although hospital-acquired infections showed an overall decrease, they were associated with higher inpatient mortality rates and other poor outcomes compared with community-acquired infections.

“Studies have identified that [C. difficile infection (CDI)] incidence has increased or even doubled between 2001 and 2010,” Omneya Mohamed, PhD, investigator for Merck, and colleagues wrote. “While the 2013 national standardized incidence ratio showed a decrease of hospital onset CDI from the 2011 baseline, there were significant differences at the state level. As costs, rates of infections and risk of readmission for CDI vary significantly by region, it is difficult for hospitals to assess their comparative burden of recurrent CDI and resulting economic and clinical consequences.”

Community-, hospital-acquired CDI burden varies by region

To better understand the regional burden of CDI, Mohamed and colleagues assessed data from the Premier Healthcare Database to investigate the costs, rates of infections and risk for readmission for CDI in patients admitted to acute care hospitals across the United States. Their analysis included 180,371 inpatient discharges who received metronidazole, vancomycin or fidaxomicin for community-onset (CDI-COM; 17.3%) or hospital onset (CDI-HO; 82.7%) CDI from January 2010 through December 2013.

Despite an increase in CDI-COM, reductions were observed in the Middle Atlantic, Pacific and West North Central regions, according to the researchers. In contrast, CDI-HO increased in the East South Central, Mountain, New England and West South Central regions. CDI-COMs were more frequent in smaller hospitals with less than 250 beds, whereas CDI-HOs were more likely to occur in urban, teaching and larger hospitals with more than 550 beds.

Inpatients with CDI-HO had higher mortality rates (9.5% vs. 7.6%) and transfers to skilled nursing facilities (44.6% vs. 36.3%), and had more than doubled lengths of stay (20.8 days vs. 10.0 days) and hospital costs ($49,668 vs. $20,378) vs. patients with CDI-COM. CDI-COM patients, however, were more likely to be readmitted within 6 weeks of their initial infection (13.9% vs. 10.8%) and subsequent readmissions (2.9% vs. 2.1%).

Results adjusted for hospital characteristics, patient demographics and comorbidities showed that patients in the East North Central region of the U.S. had shorter hospital stays while patients in the Middle Atlantic had the longest hospital stays. The lowest health care costs were reported in the East North Central and East South Central regions, and the highest costs were reported in the Middle Atlantic and Pacific regions.

“These findings may be useful in assisting individual hospitals assess their specific anticipated costs and utilization based on regional status and hospital characteristics,” Mohamed and colleagues wrote.

Overall CDI rates highest in Northeast, springtime

Earlier data published in the American Journal of Infection Control on the overall burden of CDI showed that rates of infection were highest in the Northeast region of the U.S. and in the spring.

Jacqueline R. Argamany, PharmD, from the University of Texas College of Pharmacy, and colleagues analyzed data from the CDC’s National Hospital Discharge Survey and identified 2.3 million cases of CDI from 2001 to 2010. Study data showed the highest incidence of CDI in the Northeast (8 discharges/1,000 total discharges), followed by the Midwest (6.4/1,000), South (5/1,000) and the West (4.8/1,000).

The researchers partially attributed the increased incidence of CDI in the Northeast to longer hospital stays, which can put patients at a greater risk for C. difficile, they wrote. In 2010, the average lengths of hospital stay in the Northeast were 5.5 days vs. 4.4 days in the West.

Seasonally, spring had the most cases (6.2 discharges/1,000 total discharges), followed by winter and summer (both 5.9/1,000) and fall (5.6/1,000).

“The peak incidence in the spring could be attributed to increased utilization of antibiotics in winter months,” Argamany and colleagues wrote. “Prior studies have found a 1- to 2-month lag time between antibiotic exposure and the development of CDI.”

According to the CDC, C. difficile is the most common cause of health care-associated infections in U.S. hospitals, with up to $4.8 billion in annual excess health care costs for acute care facilities alone. The agency estimates that C. difficile caused almost half a million infections in 2011 and that 29,000 U.S. patients died within 30 days of initial diagnosis.

“Results of this study may be used to direct resources and implement targeted control measures where and when they are needed most,” the researchers concluded.

References:

Argamany JR, et al. Am J Infect Control. 2015;doi:10.1016/j.ajic.2014.11.018.

Mohamed O, et al. Abstract 127. Presented at: Society of Hospital Medicine Annual Meeting; March 6-9, 2016; San Diego.

Disclosure: Mohamed is an employee of Merck. Argamany and colleagues report no relevant financial disclosures.