Epidemiological and clinical characteristics of hospitalized patients with cardiomyopathies in China: a nationwide retrospective analysis

BACKGROUND: Cardiomyopathies are major causes of heart failure and sudden cardiac death, but nationwide epidemiological data from China remain limited. Following the inclusion of several cardiomyopathies in the first national rare disease list in 2018, contemporary trends in hospitalization and in-hospital outcomes have not been systematically evaluated. This study aimed to characterize national hospitalization patterns for cardiomyopathies from 2018 to 2022. METHODS: We conducted a nationwide retrospective study using the Hospital Quality Monitoring System (HQMS), which covers secondary and tertiary hospitals across 31 provinces. Cardiomyopathies were identified using National Clinical Version 2.0 codes. We assessed age- and sex-standardized hospitalization rates, regional variation, comorbidities, device use, intensive care unit (ICU) admission, in-hospital mortality, length of stay, and hospital costs. Temporal trends were analyzed using Joinpoint regression to estimate the average annual percent change (AAPC). RESULTS: A total of 1,935,421 hospitalizations from 943,178 unique patients were included. The standardized hospitalization rate increased from 151.55 to 206.23 per 1,000,000 population (AAPC = 7.68%). Dilated cardiomyopathy was the most frequently recorded subtype. Men accounted for 67.99% of patients and were diagnosed at a younger age than women. Considerable provincial variation was observed. ICU admission increased from 2.49% to 6.97% (AAPC = 33.94%, p = 0.01), while in-hospital mortality remained stable (0.85% to 0.89%; AAPC = - 0.03%, p = 0.96). Median length of stay decreased from 8 to 7 days (AAPC = - 2.91%, p = 0.03), and median hospital costs increased from CNY 7,362 to 7,985 (AAPC = 2.13%, p = 0.03). CONCLUSIONS: Cardiomyopathy hospitalizations in China increased markedly between 2018 and 2022, with notable sex, age, and regional disparities. Rising ICU utilization alongside stable mortality suggests evolving case mix and improvements in acute care. These nationwide findings highlight unmet diagnostic and healthcare needs. TRIAL REGISTRATION: Clinical trial number: not applicable.