Changes in the proportion and severity of patients with fever or common cold symptoms utilizing an after-hours house call medical service during the COVID-19 pandemic in Tokyo, Japan: a retrospective cohort study

BACKGROUND: Trends in the characteristics and disease severity of patients using an after-hours house call (AHHC) medical service changed during the coronavirus disease (COVID-19) pandemic. However, there have been no reports on this issue since the start of the COVID-19 pandemic. This study aimed to investigate patients’ tendencies to utilize an AHHC medical service for fever or common cold symptoms during the COVID-19 pandemic. METHODS: This retrospective cohort study compared the characteristics and disease severity of patients with fever or common cold symptoms utilizing an AHHC medical service offered by a single large company between the control period (December 1, 2018 to April 30, 2019) and the COVID-19 pandemic exposure period (December 1, 2019 to April 30, 2020). We also assessed the proportion of these patients in relation to all patients calling the service for any reason. RESULTS: During the control and COVID-19 pandemic exposure periods, a total of 6462 and 10,003 patients consulted the AHHC medical service, respectively. Of these, 5335 (82.6%) and 7423 (74.2%) patients had fever and common cold symptoms, respectively, during the control and COVID-19 pandemic exposure periods (P < 0.001). The corresponding median (interquartile range) ages were 8 (3–11) and 10 (4–33) years, respectively. The distribution of disease severity differed between the groups. The proportions of patients with mild, moderate, and severe illness were 71.1, 28.7, and 0.2% in the control period and 42.3, 56.7, and 0.9% in the COVID-19 pandemic exposure period, respectively (P < 0.001). CONCLUSIONS: During the COVID-19 pandemic, the proportion of patients with fever or common cold symptoms was lower than that in the control period, but disease severity was significantly higher.