In older adults who are long-term residents of nursing homes, there is no significant association between bisphosphonate use and Clostridiodes difficile infection (CDI), according to study results published in the Journal of the American Medical Directors Association.
Bisphosphonates have been linked to a higher than expected number of CDIs in the United States Food and Drug Administration’s spontaneous adverse event reporting system. To evaluate this potential association in a population at high risk for CDI, researchers conducted a retrospective cohort study in which they examined CDI-associated hospitalizations in older adults residing in nursing homes.
The study included patients in the United States aged ≥65 years who became long-stay (>100 days) residents at nursing homes between January 1, 2008 and December 31, 2009. Using linked Medicare claims and Minimum Data Set records, patients who were new users of an oral bisphosphonate were matched 1:1 with new calcitonin users by propensity scores controlling for >100 covariates. The researchers used a Cox proportional hazards model to determine the risk for hospitalization for CDI, adjusting for previous antibiotic and proton pump inhibitor use.
Overall, 17,753 bisphosphonate users and 5348 calcitonin users were included in the study. The matched cohort consisted of 5209 bisphosphonate users and 5209 calcitonin users.
In the matched cohort, CDI-related hospitalizations occurred in 1.6% of bisphosphonate users (n=84) compared with 1.4% of calcitonin users (n=71). The researchers did not find a significant difference in the risk for hospitalization for patients using bisphosphonates compared with patients using calcitonin (hazard ratio, 1.11; 95% CI, 0.81-1.52).
Rates of antibiotic exposure up to 1 year prior to index date were similar in bisphosphonate and calcitonin users (77.3% vs 78.7%, respectively). The rate of proton pump inhibitor use in this timeframe was also comparable, with a rate of 43.8% in bisphosphonate users and 43.3% in calcitonin users.
The study had several limitations, including its reliance on administrative billing codes for hospitalizations, which may not represent the entire burden of disease in nursing homes. The researchers also noted that, despite propensity score matching, new calcitonin users may still be systematically different from new bisphosphonate users.
“C difficile infection should not be a consideration when prescribing [bisphosphonates] to frail older adults given the lack of a significant association. We continue to advocate for evaluating nontraditional and modifiable risk factors to reduce burden of C difficile infection in frail older adults,” the researchers wrote.
McConeghy KW, Zullo AR, Lary CW, et al. Association between bisphosphonates and hospitalized Clostridiodes difficile infection among frail older adults [published online January 13, 2020]. J Am Med Dir Assoc. doi:10.1016/j.jamda.2019.11.016