The study, published in BMC Health Services Research, drew on five waves of the China Health and Retirement Longitudinal Study, or CHARLS, collected in 2011, 2013, 2015, 2018, and 2020. The research team, led by Lingjie Wang and Junjie Jiang of Fujian Medical University together with collaborators at Georgetown University and the University of Georgia, focused on a population that health economists consider especially vulnerable: people aged 45 and older who reported living with multiple chronic conditions, often abbreviated as MCCs. These are individuals whose illnesses, such as hypertension, diabetes, heart disease, and chronic lung disease, accumulate over time and who typically need more hospital care than healthier peers, making any income-based barrier to admission a matter of serious equity concern.

To measure inequality, the researchers used a pair of well-established econometric tools. The first is the concentration curve, which plots the cumulative share of hospital admissions against the cumulative share of the population ranked from poorest to richest. If hospital use were distributed equally across income groups, the curve would trace a perfect diagonal line. Deviations above or below that line reveal whether care is concentrated among the poor or the wealthy. The second tool, the standard concentration index, condenses that visual picture into a single number, where a positive value signals that care favors the better-off and a negative value signals a pro-poor distribution.

The headline result is a clear downward march in that index. Among middle-aged and older Chinese adults with multiple chronic conditions, the standard concentration index stood at 0.1235 in 2011, fell to 0.0721 in 2013, edged up slightly to 0.0780 in 2015, then dropped to 0.0447 in 2018 and again to 0.0357 in 2020. In plain terms, hospital care in this population was consistently tilted toward the richer half of society throughout the decade, but that tilt weakened by roughly seventy percent over the study period. The only interruption came between 2013 and 2015, when the gap widened modestly before resuming its decline.

What makes this study more than a trend report is its decomposition analysis, a technique that breaks the change in the concentration index into contributions from individual factors, such as income itself, medical expenditure, insurance coverage, smoking, and demographic characteristics. Each factor receives a percentage contribution to the change in inequality between two adjacent survey waves, allowing researchers to see which forces pushed the gap wider and which pulled it narrower. This is where the study reveals some genuinely surprising mechanics behind the headline numbers.

In the first transition, from 2011 to 2013, medical expenditure emerged as the dominant driver, contributing minus 90.74 percent to the change in inequality. The negative sign indicates that shifts in out-of-pocket spending patterns actually exacerbated the income-related disparity during those early years, even as the overall index was falling. In other words, the initial narrowing of the gap happened despite, not because of, the way medical costs were distributed across income groups, suggesting that other forces, including broader economic growth and expanding insurance enrollment, were doing the heavy lifting.

The 2013 to 2015 period, the one interval in which inequality worsened, produced perhaps the most striking finding of the entire analysis: smoking contributed 512.50 percent to the increase in the concentration index. The researchers’ interpretation is that smoking behavior, which is strongly patterned by income and education in China, interacted with hospital use in a way that disproportionately benefited wealthier smokers or disadvantaged poorer ones during this window. The magnitude of the contribution underscores how a seemingly unrelated behavioral risk factor can become a powerful engine of health care inequity when it clusters along socioeconomic lines.

The final two transitions turned the spotlight on insurance, and the results form a cautionary tale about the design of coverage schemes. Between 2015 and 2018, commercial insurance contributed 273.91 percent toward alleviating inequality, while the New Rural Cooperative Medical Insurance, the flagship scheme covering China’s rural population, contributed minus 117.39 percent toward exacerbating it. Then, between 2018 and 2020, the roles reversed dramatically: commercial insurance contributed minus 522.73 percent, worsening the disparity, while the rural cooperative scheme contributed 263.64 percent, helping to reduce it. The authors suggest that these swings reflect how the two insurance types reached different populations at different times, with commercial plans initially covering better-off urban residents and later expanding in ways that deepened stratification, while the rural scheme matured into a more effective equalizer as its reimbursement levels improved.

For readers unfamiliar with China’s health insurance landscape, the stakes of these findings are considerable. The country built the world’s largest health insurance system in roughly a decade, enrolling more than 95 percent of its 1.4 billion people through three main schemes: Urban Employee Basic Medical Insurance for formal-sector workers, Urban Resident Basic Medical Insurance for other urban dwellers, and the New Rural Cooperative Medical Insurance for the rural majority. Because reimbursement rates, benefit packages, and the underlying health of enrollees differ sharply across these schemes, insurance design has become one of the most consequential levers for health equity in the country. The new study provides rare longitudinal evidence on how those design choices translated into real hospital access for the chronically ill.

The study’s conclusions come with a note of guarded optimism. The authors write that income-related inequality in inpatient care utilization among Chinese middle-aged and older adults with multiple chronic conditions declined over the decade, showing a pro-poor change trend, and they emphasize that despite the impressive reductions, it remains important to maintain and improve equal access to hospital care. They point toward future interventions and policies that could target the economic circumstances of socially and economically vulnerable individuals and strengthen their ability to cope with the mounting burden of chronic disease. As populations age across Asia, Europe, and North America, and as multimorbidity becomes the norm rather than the exception in later life, the Chinese experience documented here offers a template, and a warning, for any health system hoping to measure, understand, and ultimately close the gap between the hospital care that the rich receive and the care that everyone else needs.

Subject of Research: Income-related inequality trends in inpatient care utilization among Chinese middle-aged and older adults with multiple chronic conditions

Article Title: Trend in income-related inequalities in inpatient care utilization among Chinese middle-aged and older adults with multiple chronic conditions, 2011–2020

Article References: Wang, L., Jiang, J., Zeng, W., Khan, M. M., Li, C., & Liu, W. (2026). Trend in income-related inequalities in inpatient care utilization among Chinese middle-aged and older adults with multiple chronic conditions, 2011–2020. BMC Health Services Research. https://doi.org/10.1186/s12913-026-15791-6

Image Credits: AI Generated

DOI: 10.1186/s12913-026-15791-6

Keywords: health inequality, inpatient care, multiple chronic conditions, China, CHARLS, concentration index, health insurance, aging, health economics, health policy, multimorbidity, health services research