Impact of Non-Pharmaceutical Interventions on the Incidence and Treatment of Chronic Rhinosinusitis during the COVID-19 Pandemic: A Nationwide Retrospective Cohort Study

Many countries have implemented non-pharmaceutical interventions (NPIs) to prevent the spread of COVID-19. However, the impacts of NPIs on the epidemiology and treatment of chronic rhinosinusitis (CRS) remain unclear. We analyzed 671,216 patients to investigate changes in the incidence rate and treatment frequency of CRS using Korean nationwide health insurance data between 2017 and 2021. The incidence rate (p < 0.001) and the number of outpatients (p < 0.001), patients hospitalized (p < 0.001), and patients prescribed antibiotics (p < 0.001) or steroids (p = 0.024) were significantly lower in the pandemic period than in the pre-pandemic period; however, the number of patients who underwent surgery was not different (p = 0.205). Additionally, the frequency of surgeries per patient was significantly lower in patients during the pandemic period (p < 0.001). In the interrupted time series analysis, the trends in the number of outpatients (p < 0.001), patients hospitalized (p < 0.001), patients who underwent surgery (p < 0.001), and patients prescribed antibiotics (p < 0.001) or steroids (p < 0.001) significantly changed after the onset of the COVID-19 pandemic. In summary, NPI implementation during the COVID-19 pandemic was associated with a reduction in the incidence and treatment of CRS.