Epidemiological trends of Bell's palsy treated with steroids in Korea between 2008 and 2018

Introduction Contemporary epidemiological data on Bell's palsy are crucial to clarify disease burden and improve management strategies. We aimed to examine the epidemiology of, and factors associated with, Bell's palsy treated with steroids in Korea. Methods Using the National Health Insurance claims data from 2008 to 2018, we determined the incidence, recurrence rate, and management trends of Bell's palsy treated with steroids. We defined Bell's palsy cases based on diagnostic codes and concurrent treatment with steroids. Results The incidence of Bell's palsy showed an increasing trend (from 23.0 per 100 000 persons in 2008 to 30.8 per 100 000 persons in 2018). Age (60-69 y), sex (men), and month (January) were risk factors of Bell's palsy. The recurrence rate of Bell's palsy over the 11-y period was 1.5%. Male sex (hazard ratio [HR], 1.1; 95% confidence interval [CI], 1.0-1.2) and physiotherapy (HR, 0.9; 95% CI, 0.8-0.99) were independently associated with the recurrence of Bell's palsy. During the study period, the use of electrodiagnostic testing steadily increased, whereas that of physiotherapy steadily decreased, and antiviral therapy fluctuated,. Discussion The incidence and recurrence rates presented in this study are comparable with those reported in earlier studies that included patients with Bell's palsy, regardless of the use of steroids, and documented an increase in the burden of Bell's palsy. Further randomized controlled trials are required to ascertain the long-term effects of physiotherapy on recurrent Bell's palsy.