[Characteristics of rare diseases in Zhejiang province, 2007-2017].

Objective To understand the characteristics of 24 388 inpatients with rare diseases in Zhejiang province during 2007-2017 and provide evidence for rare disease prevention and control. Methods Inpatient data of rare diseases and the number of hospitalization in each year were collected in 10 hospitals of class Ⅲ (A) in Zhejiang province from 2007 to 2017, and descriptive statistical analysis was used. Results A total of 24 388 cases of rare diseases were found, accounting for 2.69‰ (24 388/9 054 201) of total hospitalized cases. The top 3 types of rare diseases were "diseases of blood and blood-forming organs and certain disorders involving immune mechanism" (32.81%, 8 001/24 388), "congenital malformations, deformations and chromosomal abnormalities" (24.87%, 6 065/24 388) and "diseases of the nervous system" (19.01%, 4 635/24 388). The number of rare disease cases increased year by year from 2007 to 2017 with an average annual growth of 19.69%, however, the proportion of rare disease cases in the annual number of hospitalized cases only showed upward trend during 2016-2017, the time distribution of different types of rare diseases had different characteristics. The male to female ratio of rare diseases cases was 1.35∶1(13 990/10 398), "diseases of the digestive system" (4.45∶1, 1 180/265), "consequences of injury, poisoning and other external causes" (3.51∶1, 281/80) and "diseases of the nervous system" (2.26∶1, 3 213/1 422) had the highest male to female ratio. The distributions of rare disease types and diseases of different types in different age groups varied. The top 10 rare diseases accounted for 53.55% (13 060/24 388) of the total cases, and the top 3 diseases were adult idiopathic neutropenia (14.41%, 3 515/24 388), corticobasal degeneration (7.60%, 1 854/24 388) and henock-schoenlein purpura (6.01%, 1 466/24 388). Conclusion The analysis on the characteristics of 24 388 rare disease cases in Zhejiang during 2007-2017 provided reference evidence for the promotion of rare disease research, monitoring, building registration database, and development of the prevention and control strategy for rare diseases in China. Key words: Rare disease; Inpatient; Case characteristic