Using inpatient data to estimate the prevalence of Wegener's granulomatosis in China.

China lacks a registry for most rare diseases, so specific epidemiological data on those diseases are lacking. A strategy involving the DISMOD II model was recently formulated to estimate the epidemiological parameters of rare diseases, and this strategy has been used to study several rare diseases. The current study used this strategy to estimate the prevalence of one such rare disease, Wegener's granulomatosis (WG), in China based on its incidence, mortality, and rate of remission according to the software tool DISMOD II. The incidence of WG was calculated based on inpatient data from 100 hospitals throughout China. The cause-specific mortality from WG was estimated based on data from the National Vital Statistics System of the United States and adjusted for the Chinese population. The rate of disease remission was based on the results of previous study. The current results indicated that the prevalence of WG in China is 1.94/100,000, which is slightly lower than that in Europe and the United States. The mean age at onset of WG in China was calculated to be 38.9 years for males and 39.3 years for females and the duration of disease was 28 years for both male and female patients. These figures are similar to published data from other countries. In conclusion, the DISMOD II model was used to estimate the prevalence of WG in China, providing a basis to evaluate the potential disease burden and orphan drug use by patients with WG. The DISMOD II model could be used to estimate the prevalence of other rare diseases.