Prevalence and Burden of Chronic Spontaneous Urticaria in Japan: A Cross-Sectional Study.

Background: Real-world data on the prevalence and burden of patients with chronic spontaneous urticaria (CSU) are limited in Japan. This study aimed to estimate CSU prevalence and assess its humanistic and economic burden. Methods: This analysis utilized data from Japanese adult respondents self-reporting physician-diagnosed CSU collected through the 2019 National Health and Wellness Survey. The weighted 12-month prevalence was estimated using 2018 international census projections. Outcomes included the SF-12v2 (physical and mental component summary [PCS and MCS] scores), health utility index (SF-6D and EQ-5D), Dermatology Life Quality Index (DLQI), Generalized Anxiety Disorder-7, Patient Health Questionnaire-9, Work Productivity and Activity Impairment scores at data collection, and healthcare resource utilization over the past 6 months. Results: Among 30,006 respondents, 334 reported having CSU, of whom 62.3% were female. The mean (SD) age at data collection and CSU diagnosis was 50.8 (15.3) and 39.2 (14.9) years, respectively. The weighted prevalence of CSU was 1.1%. The mean (SD) PCS and MCS scores were 50.3 (7.0) and 45.1 (10.0), respectively. The mean (SD) health utility measures (SF-6D and EQ-5D) were 0.71 (0.13) and 0.79 (0.18), respectively. The mean (SD) DLQI score was 3.8 (6.0). More than 40% of patients reported mild/moderate/severe anxiety and depression. The mean % (SD) scores for absenteeism, presenteeism, overall work impairment, and activity impairment were 7.6 (17.6), 27.2 (27.2), 30.3 (29.6), and 28.5 (27.8), respectively. Approximately 90.0% of patients visited healthcare providers, including emergency room visits (6.9%) and hospitalizations (9.9%). Conclusions: This study provides insights into the diagnosed prevalence and burden of CSU in Japan, highlighting its impact on patients' lives.