674The incidence and risk factors of acute infectious diarrhea at Japanese geriatric intermediate care facilities.

Background Norovirus infection and Clostridioides difficile infection (CDI) are major causes of acute infectious diarrhea at medical facilities. "Geriatric intermediate care facilities" are a type of medical facility that tend to the daily life needs of elderly Japanese people. However, there is no research about norovirus- or CDI-related diarrhea at Japanese geriatric intermediate care facilities. Methods This prospective cohort study included 1445 residents at 10 geriatric intermediate care facilities in Osaka between November 2018 and October 2019. The study subjects were followed regarding the occurrence of acute infectious diarrhea and the results of rapid diagnostic tests for norovirus and CDI. We calculated incidence rates and hazard ratios (HR) with 95% confidential intervals (CI) to identify the risk factors of infectious diarrhea. Results Thirty-seven residents developed diarrhea during the observation period, although none of them was positive for norovirus or CDI. The total incidence rate was 1.21/10,000 person-days (95%CI: 0.82-1.60). Compared with residents aged 87-91 years, those aged ≤ 80 years had a significantly higher risk of diarrhea (HR = 3.85, 95%CI: 1.27-11.66). Moreover, residents with thyroid diseases had a significantly higher risk of diarrhea than those without thyroid disease (HR = 5.33, 95%CI: 2.32-12.25). Conclusions The incidence of acute infectious diarrhea is relatively low. However, residents who are < 80 years old and those with thyroid diseases are more likely to develop diarrhea. Key messages We describe the situation of acute infectious diarrhea at Japanese geriatric intermediate care facilities [ABSTRACT FROM AUTHOR]