WASHINGTON – March is the month when hospitals see more Clostridium difficile infections, and the Northeast is the region that leads the nation in the difficult to treat infection, researchers reported here.
Overall, the in-hospital incidence for C. difficile was 8.0 cases of the infection for every 1000 discharges in the Northeast region, followed by the Midwest with 6.4 cases per 1000 discharges; the South with 5.0 cases of C. difficile per 1000 discharges and the West which recorded 4.8 C. difficile discharges per 1000, said assistant professor of pharmacy at the University of Texas, Austin. All the differences were statistically significant (P<0.0001), she reported.
The incidence of C. difficile in hospital nearly doubled from 4.5 cases of C. difficile per 1000 hospital discharges in 2001 to 8.2 cases per 1000 discharges in 2010, she said in her presentation at the Interscience Conference on Antimicrobial Agents and Chemotherapy, sponsored by the American Society for Microbiology.
Reveles and colleagues performed a retrospective analysis of more than 2.3 million cases of C. difficile treated from 2001 to 2010 included in the CDC's National Hospital Discharge Survey. The patients were treated at non-federal short-stay hospitals. Because the survey does not include information from larger hospitals, Reveles said that the finding might not be generalizable to those facilities.
In March, there were 7.6 cases of C. difficile per 1000 hospital discharges; the next closest month was May with 7.3 cases of C. difficle per 1000 hospital discharges, Reveles told 51˶.
For the study, she identified C. difficile discharges involving 2,184,584 adults and 82,588 pediatric patients defined as those 17 years of age and younger. About 59% of the adults were women compared with 40% of the pediatric population (P<0.0001). The adults were about 75 years of age; the median age for the children was 5 years. About 2/3 of the adults were admitted through the emergency department; about 43% of the pediatric patients came into the emergency department.
Overall, mortality among adults was 7.1%; mortality among children was 1.4%, Reveles said.
There were differences in mortality by region, the researchers reported. The highest mortality due to C. difficile was in the Midwest with 7.4% of the patients diagnosed with the infection dying, compared with 6.9% in the South and in the Northeast and 6.1% in the West.
Median hospital length of stay was 8 days for the adults; 6 days for the children (P=0.0003).
The researchers determined that spring time is when hospitals should gird for influx of cases of C. difficile. She said there is a lag time from the winter period – defined as December through February – when more use of antibiotics for colds and influenza creates a window of opportunity for C. difficile to emerge.
"Antibiotics continue to be the primary risk factor for emergence of C. difficile due to significant disruption of gastrointestinal flora," Reveles said. "The highest use of antibiotics is during the winter due to higher prevalence of respiratory diseases. Fluoroquinolones and cephalosporins – often linked to C. difficile – are used more frequently in the winter months."
"Patients hospitalized for C. difficile are likely to stay in the hospital for 1-2 weeks," she said.
Overall, incidence is highest in spring with 6.2 cases of C. difficile were seen per 1000 hospital discharges, compared with 5.9 cases per 1000 discharges in the winter and summer and 5.6 cases per 100 hospital discharges in autumn.
Although not the highest for incidence, winter is deadly – with a mortality of 7.9% for that season compared with 6.8% in summer, 6.6% in fall and just 6.2% in spring – when the incidence is highest, Reveles said.
"I think that this is not the first time that the rates of recorded C. difficile infection have come out higher in the Northeast, and base question is: Is this an ascertainment issue in that there may be more testing or not the same level of testing in other areas as there is in the Northeast?" said session moderator professor of medical microbiology at the University of Leeds, England.
Reveles said there may be multiple reasons why the Northeast has a greater incidence of C. difficile but a lower mortality rate and "certainly testing could be one of those reasons." Confounders, though, she said was that the Northeast has longer hospital stays and more elderly patients than the other regions.
Disclosures
Reveles and Wilcox disclosed no relevant relationships with industry.
Primary Source
Interscience Conference on Antimicrobial Agents and Chemotherapy
Source Reference: Reveles K, et al "Regional and seasonal variation in Clostridium difficile infections among hospitalized adults and children in the United States, 2001 to 2010" ICAAC 2014; DOI: Abstract 2021.