Clinic characteristics of psoriasis in China: a nationwide survey in over 12000 patients.

Psoriasis is a worldwide chronic inflammatory disease, involving both skin and joints. In order to characterize psoriasis in Han Chinese population, we conducted this nationwide prospective and hospital based survey, in which 56 hospitals with departments of dermatology participated, located in 33 cities across China. A total of 12,031 outpatients with psoriasis were registered during 2009 to 2010, which the data was collected by standard questionnaires. The main data acquisition included demographics, family history, disease status and other comorbidities. Physical and dermatological examination, including body surface area (BSA) and psoriasis area severity index ( PASI) were applied to evaluate the disease severity. Descriptive statistics, 2 tailed t-test and chi-square test were used appropriately for the statistical analysis. From the study, we found that the male and female ratio of the patients was 1.49: 1. Mean age of onset was 30.2 +/- 14.5 years for males and 27.1 +/- 15.6 years for females (P < 0.05). Scalp was the most common onset site (52.8%), The mean PASI was 18.70 +/- 10.01, indicating that most patients presenting at the hospitals had moderate-to-severe psoriasis and the majority was psoriasis vulgaris (96.5%). Among 12,031 patients, 23.1% had a family history of psoriasis, 16.1% had comorbidities, and 29.9% had nail changes. The most important aggravation factor was season change (60.2%), followed by psychological stress (34.5%), and there significant differences between genders on trigger factors. In conclusion, this study characterizing psoriasis in Han Chinese population, could be used as basic data for future study.