Hospitalized Patients May Be Bringing C. Diff Home to Their Loved Ones

— Study suggests asymptomatic colonization plays a large role in household transmission

MedpageToday
A computer rendering of Clostridioides difficile bacteria.

There was a higher incidence of Clostridioides difficile infection among households where a family member was recently discharged from the hospital but not formally diagnosed with such an infection, a study of insurance claims data found.

In the analysis of more than 140 million insurance enrollees, individuals exposed to a recently hospitalized family member (who did not have a diagnosed C. difficile infection) still had a 73% higher incidence of infection within 60 days of the discharge versus enrollees without a recently hospitalized family member (unadjusted incidence rate ratio [IRR] 1.73), reported Aaron Miller, PhD, of the University of Iowa in Iowa City, and colleagues.

Adjusted analyses showed a dose-response relationship based on length of hospital stay, according to the findings in Emerging Infectious Diseases. Compared to households without a recent hospitalization, IRRs for a C. difficile infection ranged from 1.30 (95% CI 1.19-1.41) when the family member was hospitalized for 1 to 3 days up to 2.45 (95% CI 1.66-3.60) when the hospitalization lasted a month or more.

Since C. difficile infection has been linked to hospitals, most research has focused on that setting. But asymptomatic colonization is not uncommon, as a meta-analysis found that 10% of patients hospitalized in North America could be colonized and "could represent a large reservoir of CDI [C. difficile infection] outside healthcare settings," Miller's group noted.

"This is the first large-scale study to document risk associated with exposure to a recently hospitalized family member where the hospitalized family member was not symptomatic," Miller told MedPage Today. "Exposure to family members who have been recently hospitalized is not typically thought of as a risk factor for C. difficile infection."

For their study, the team examined national insurance claims data from IBM MarketScan Research Databases on 142,125,247 enrollees from 2001 to 2017. Those included were from households with at least two family members enrolled in the same insurance plan who were not diagnosed with C. difficile infection within the past 60 days, as identified by ICD-9 and ICD-10-CM codes.

Of the 164,650 C. difficile cases identified, 3,871 cases were classified as potential asymptomatic transmission from a recently hospitalized family member. Overall, there were 5.56 infections per 100,000 enrollment months in households with a recently hospitalized family member compared with 3.22 per 100,000 among households without one.

Adults over 65 had the greatest incidence of infection (IRR 9.32 vs those under 18 years, 95% CI 8.92-9.73), followed by individuals on "high-CDI risk antibiotics" (IRR 8.83, 95% CI 8.63-9.03). Use of proton pump inhibitors was also a significant risk factor (IRR 2.23, 95% CI 2.15-2.30), and incidence of C. difficile infection was higher among women and households with an infant, the researchers noted.

"If patients who are asymptomatically colonized during a hospital stay contribute to transmission in the community, not all CDI cases attributable to hospital exposure can be directly identified based on hospital discharge records," Miller and colleagues wrote. "Asymptomatic C. difficile carriers discharged from hospitals could be a major source of community-associated CDI cases and should be considered during surveillance and intervention-based investigations."

The authors acknowledged limitations to the data, including that they could not identify the exact point of C. difficile transmission and that there was no laboratory test results or genetic data to confirm diagnoses. Also, it could not be confirmed whether enrollees of the same plan were necessarily living in the same household.

"In the future, we plan to further investigate direct household linkages to establish genetic relationships between asymptomatic hospital exposure in one family member and secondary transmission within the household," Miller said.

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    Zaina Hamza is a staff writer for MedPage Today, covering Gastroenterology and Infectious disease. She is based in Chicago.

Disclosures

Miller and coauthors did not disclose any conflicts of interest.

Primary Source

Emerging Infectious Diseases

Source Reference: Miller AC, et al "Risk for asymptomatic household transmission of Clostridioides difficile infection associated with recently hospitalized family members" Emerg Infect Dis 2022; 28 (5): Published on April 13, 2022.