Physical multimorbidity, health service use and catastrophic health expenditure by socio-economic groups in China::a population-based panel data analysis

Background Multimorbidity, the presence of two or more mental or physical chronic non-communicable diseases (NCDs), is a major challenge for the health system in China, which faces unprecedented ageing of its population. This study examined: (1) the distribution of physical multimorbidity in relation to socio-economic status, (2) the relationships between physical multimorbidity, healthcare service use, and catastrophic health expenditures, and (3) whether these relationships varied by socio-economic groups and social health insurance schemes. Methods Panel data study design utilized three waves of the nationally-representative China Health and Retirement Longitudinal Study (CHARLS 2011, 2013, 2015), which included 11 718 participants aged ≥50 years, and 11 physical NCDs. Findings Overall, 62% of participants had physical multimorbidity in China in 2015. Multimorbidity increased with age, female gender, higher per capita household expenditure, and higher educational level. However, multimorbidity was more common in poorer regions compared with the most affluent regions. An additional chronic NCD was associated with an increase in the number of outpatient visits of 28.8% (IRR=1.29, 95% CI: 1.27 to 1.31), and days of hospitalisation (IRR=1.38, 95% CI: 1.35 to 1.41). There were similar effects in different socio-economic groups and among those covered by different social health insurance programmes. Overall, multimorbidity was associated with a substantially greater odds of experiencing CHE (AOR=1·29 for the overall population, 95% CI=1·26, 1·32). The effect of multimorbidity on catastrophic health expenditures persisted even among the higher socio-economic groups and those with more generous health insurance coverage.Interpretation Multimorbidity was associated with higher levels of health service use and greater financial burden. Concerted efforts are needed to reduce health inequalities that arise due to multimorbidity, and its adverse economic impact in population groups in China. Social health insurance reforms must place emphasis on reducing out-of-pocket spending for patients with multimorbidity to provide greater financial risk protection.