Inequalities in health services utilization and catastrophic health expenditures among patients with chronic respiratory diseases in China: An empirical analysis based on the CHARLS, 2013—2020

Background Chronic respiratory disease (CRD) is a global priority in preventing and controlling non-communicable diseases (NCDs). Its disease burden and health inequalities significantly undermine population health outcomes. This study examines inequalities in health service utilization and CHE incidence among middle-aged/elderly CRD patients in China, identifying key drivers. Methods Using 2013–2020 China Health and Retirement Longitudinal Study(CHARLS) data, this study analyzed outpatient, inpatient, and physical examination utilization rates and CHE incidence in CRD patients ≥ 45 years. The degree of inequality and its main contributing factors were measured using indirect standardization, the concentration index (CI), and decomposition analysis. Results All service utilization rates increased from 2013 to 2020. CIs declined but remained positive in 2020 (outpatient: 0.020; inpatient: 0.059; physical examination: 0.017). Health behaviors reduced outpatient inequality, while age 65 and above drove inpatient and physical examination disparities. CHE incidence rose from 10.40% (2013) to 11.67% (2020), with CIs worsening (-0.027 to -0.048). Urban residence (13.55%) and non-agricultural hukou (8.82%) were the main drivers of inequality at CHE. Conclusions Although equity improved in outpatient, inpatient, and physical examination service utilization during the study period, persistent pro-rich inequalities remain. CHE incidence demonstrated widening pro-poor disparities. Policy priorities should target unmet needs and economic burdens among socioeconomically disadvantaged groups through strengthened health education, behavioral interventions, health insurance reforms, and enhancements to the primary care system.