This study plans to calculate the prevalence and incidence of palmoplantar pustulosis and generalized pustular psoriasis based on the national medical insurance data and analyze the composition characteristics and some clinical features of patients, through taking into account of the research status of palmoplantar pustulosis and generalized pustular psoriasis and the characteristics of medical insurance data.

Inclusion Criteria:

• The insured population of the national urban employee basic medical insurance and the urban resident basic medical insurance from January 1, 2012, to December 31, 2016 (60 months) (the denominator)
• The patients have been diagnosed with palmoplantar pustulosis or generalized pustular psoriasis (including disease name, English abbreviation and ICD code)
• Both outpatient and inpatient patients are included

Exclusion Criteria:

• The individuals whose information is only contained in the reimbursement settlement database but not in the insurance coverage database will be considered as invalid reimbursement individuals and be excluded from the study (the denominator)
• The patients have been diagnosed with non-PPP and -GPP diseases, such as pustular psoriasis in palm and toe, pustular arthritis osteitis and SAPHO syndrome

This study used the Urban Employee Basic Medical Insurance (UEBMI) data from 2012 to 2016 to calculate the epidemiological characteristics of palmoplantar pustulosis and generalized pustular psoriasis. The database includes basic medical insurance data for urban workers and basic medical insurance data for urban residents, which covers 31 provinces, municipalities and autonomous regions. By the end of 2016, the number of people participating in the national basic medical insurance exceeded 1.3 billion, and the coverage rate of the insurance was stable at over 95%.

The database is composed of an insurance coverage database and a reimbursement settlement database. The insurance coverage database involves demographic information, insurance information and payment information; and the reimbursement settlement database involves medical information, disease information and expense information.