Characteristics and hospitalization burden of rare disease inpatients in Northern Henan, 2018–2025: a single-center retrospective observational study

Rare diseases are characterized by low prevalence, high heterogeneity, and substantial health burden. China has released two national rare disease lists in 2018 and 2023, but data on hospitalized rare disease patients in northern Henan remain limited. This study aimed to describe the clinical characteristics, hospitalization burden, and readmission patterns of rare disease inpatients at a tertiary hospital in northern Henan. This single-center, hospital-based retrospective observational study included rare disease inpatients admitted to the First Affiliated Hospital of Henan Medical University between January 2018 and December 2025. Cases were identified using ICD-10 codes corresponding to the two national rare disease catalogs. Data on demographics, clinical characteristics, hospitalization costs, and readmissions were extracted. Descriptive statistics, wavelet analysis, ARIMA modeling, and readmission rate calculation were performed. A total of 3,496 cases were included, accounting for 0.38% of all hospitalizations. Males accounted for 55.6% ( n = 1,944) and females 44.4% ( n = 1,552); the mean age was 49.56 ± 24.52 years. The annual number of cases increased, peaking in 2025 (1,098cases, 31.4%). Nervous system diseases (29.1%) and respiratory system diseases (21.4%) were the most common categories. Idiopathic pulmonary fibrosis was the most frequent single disease (745cases, 21.3%). The highest mean total hospitalization cost was observed for perinatal diseases (35,800 ± 26,037 CNY), while tumor-related rare diseases also showed high costs (20,353 ± 19,955 CNY). Among the top 15 diseases ranked by readmission rate, ANCA-associated vasculitis had the highest rate (83.5%) and multiple system atrophy the lowest (9.7%). Wavelet analysis showed no significant monthly periodicity, and ARIMA modeling predicted a continued upward trend in 2026. Geographically, 98.1% of cases came from five cities, with Xinxiang predominating. The rare disease inpatient burden at this tertiary center increased from 2018 to 2025, with nervous system and respiratory diseases predominating. Rare diseases varied widely in age distribution, imposed substantial economic burdens, and showed marked differences in readmission rates. These findings provide an important evidence base for optimizing regional rare disease care capacity and informing healthcare policy.