OBJECTIVES: Prurigo nodularis (PN) is a chronic dermatosis characterized by extraordinarily itchy nodules. This study aimed to describe the epidemiology, demography and comorbidities of PN.

METHODS: Data were obtained from Tianjin Urban Employee Basic Medical Insurance database (2016-2020). Prevalence and incidence of PN were estimated in 2020. Patient characteristics and comorbidities were assessed among the prevalent patients between Jan 2017 to Dec 2019. Comorbidity analysis was calculated using the ICD-10-codes and diagnosis records of the corresponding conditions.

RESULTS: Out of 1,783,447 insured persons in 2020, 2338 PN patients were identified with 413 of them were newly diagnosed, corresponding to annual prevalence rate of 0.13% and annual incidence rate of 0.02%. The prevalence was higher among males than females (0.15% vs. 0.12%, p＜0.001), and a positive correlation was seen between prevalence and age (R = 0.95, p = 0.0003). The average clinic attendance rate was estimated as 28.6%. During the selection period from Jan 2017 to Dec 2019, 1,503 prevalent patients were identified, with mean age of 54.4±0.4 years, 61.1% being male. The mean adjusted Charlson Comorbidity Index (aCCI) of PN patients was 2.6±2.6. The cardio- and cerebrovascular diseases were common comorbidities among patients with PN including hypertension (55.1%), coronary heart disease (50.9%), lipid disorders (38.6%) and cerebrovascular disease (21.5%). Mental health disorders including sleep disorder (22.8%) and anxiety (7.45%), and atopic and allergic diseases including urticaria (11.5%), asthma (9.5%), allergic rhinitis (8.1%) and atopic dermatitis (1.45%) were also common comorbidities.

CONCLUSIONS: This study provides the incidence and prevalence data of PN in China, which are comparable with previous studies. A predominance in males and older patients are noted of PN patients. PN is also significantly associated with comorbidities, especially like hypertension, coronary heart disease and sleep disorder.