The study, led by Long Chen and colleagues at the Arthritis Clinic and Research Center of Peking University People’s Hospital, pooled data from six harmonized longitudinal cohorts: the China Health and Retirement Longitudinal Study (CHARLS), the English Longitudinal Study of Ageing (ELSA), the Health and Retirement Study (HRS) in the United States, the Korean Longitudinal Study of Aging (KLoSA), the Mexican Health and Aging Study (MHAS), and the Survey of Health, Ageing and Retirement in Europe (SHARE). These surveys collectively follow hundreds of thousands of older adults using comparable questionnaires, a harmonization effort coordinated through the Gateway to Global Aging Data platform and supported by the US National Institute on Aging. Because the same walking-difficulty questions appear across all six cohorts, the researchers could ask whether the signal holds across radically different health systems, economies, and cultures.

The mortality findings are the study’s statistical backbone. Using cohort-specific Cox proportional hazards models combined through a DerSimonian-Laird random-effects meta-analysis, the team found that older adults reporting walking difficulty faced roughly double the mortality risk of those without it. The pooled hazard ratio was 2.21, with a 95 percent confidence interval of 2.06 to 2.36, based on five cohorts that provided the necessary survival data. In plain terms, an older adult who struggles to walk was more than twice as likely to die during follow-up as an otherwise comparable peer who walks without difficulty. That is an effect size comparable to major established risk factors, captured here with nothing more than self-reported mobility status.

The sheer diversity of the cohorts, however, meant the association was not perfectly uniform. The researchers reported substantial between-cohort heterogeneity, quantified by an I² statistic of 73.8 percent, meaning that nearly three-quarters of the variability across studies reflected real differences rather than chance. To probe this, they ran a sensitivity analysis using restricted maximum likelihood estimation with Hartung-Knapp inference, a more conservative statistical framework designed for small numbers of pooled studies. That analysis produced a hazard ratio of 2.18 with a wider confidence interval of 1.87 to 2.53, and a 95 percent prediction interval spanning 1.66 to 2.87. The prediction interval matters: it tells us that if the study were repeated in a new country, the true hazard ratio would very likely fall between about 1.7 and 2.9. The direction and magnitude of the association are robust; the exact strength varies by setting, likely reflecting differences in cause-of-death patterns, healthcare access, and baseline functional status across nations.

Mortality is only half the story. The second pillar of the study examined whether walking difficulty also captures what health services researchers call measured need—the diagnosable, quantifiable burden of illness that care ought to respond to. Here the evidence was emphatic. Older adults with walking difficulty had more than three times the odds of multimorbidity, the co-occurrence of multiple chronic conditions, with an odds ratio of 3.05 and a remarkably tight confidence interval of 2.98 to 3.13 across the pooled data. In absolute terms, walking difficulty came with a 25.1 percentage-point higher prevalence of multimorbidity. The authors also linked mobility limitation to limitations in activities of daily living and instrumental activities of daily living, the everyday tasks such as dressing, bathing, shopping, and managing medications that determine whether an older person can live independently. In short, the person who says walking is hard is very often the person carrying the heaviest load of disease and disability.

This is precisely what makes walking difficulty attractive as a policy instrument. Clinical risk scores require laboratory tests, diagnosis codes, and trained assessors. Socioeconomic gradients require detailed income and education data. But a mobility question costs nothing, is understood across cultures, and is already embedded in the world’s major aging surveys. If health systems want to identify the highest-need older adults for outreach, case management, or preventive care, the study suggests that a functional question can triage risk almost as well as instruments that are far more expensive to administer.

The study’s most consequential findings, however, concern what happens after high-need older adults enter the healthcare system. Using cohorts with linked healthcare utilization data—CHARLS, HRS, SHARE, and MHAS—the researchers applied the relative index of inequality (RII) and the slope index of inequality (SII), standard epidemiological tools for quantifying social gradients across the entire education distribution rather than just comparing extremes. After statistically adjusting for measured need, they asked a pointed question: among people who are equally sick, does care reach them equally?

The answer, in three of the four cohorts, was no. For any-care contact—whether an older adult had any contact with a physician or health service—higher educational position was associated with greater need-adjusted healthcare response in CHARLS, HRS, and SHARE. The MHAS estimate pointed in the same direction but was statistically imprecise. Because the population studied was restricted to older adults with walking difficulty—people already identified as high need—the gradients cannot be explained away by the educated simply being healthier. The sicker-poorer pattern had already been held constant; what remained was a systematic tendency for care to track social position.

To make the abstract indices tangible, the researchers translated the education-related gaps into standardized scenarios expressed per 1,000 high-need older adults. In HRS and SHARE, the scenario gaps amounted to roughly 15.6 to 15.7 additional care contacts per 1,000 high-need adults favoring the more educated, a modest but measurable tilt. In Mexico’s MHAS, the estimated gap was 70.0 additional contacts per 1,000, with a confidence interval of 27.8 to 101.0. In China’s CHARLS, the scenario gap ballooned to 296.7 additional contacts per 1,000 high-need adults, with a confidence interval of 74.9 to 456.8—an enormous differential in a country where hundreds of millions of people are entering old age. The authors are careful to note that these standardized scenarios are policy benchmarks rather than causal estimates of what would happen under any specific intervention; they quantify the size of the inequity, not the effect of fixing it.

The evidence on cost-related unmet need—older adults skipping care because they could not afford it—was clearest in SHARE, the European survey, where the linked data allowed the cleanest measurement. This finding connects the study to a broader policy conversation: in systems with high out-of-pocket costs, financial barriers compound the mobility barriers that already make it harder for disabled older adults to reach care. The study’s education gradient likely operates through multiple channels—health literacy, the ability to navigate complex systems, persistence in seeking appointments, and the financial means to act on symptoms—rather than through discrimination alone.

What emerges is a two-part message with global relevance. First, walking difficulty is a pragmatic, validated marker of the highest-need older adults, doubling mortality risk and flagging a multimorbidity burden three times higher, and it can be ascertained anywhere a questionnaire can reach. Second, within this high-need population, healthcare response still follows the gradient of education, with the magnitude of the inequity varying dramatically—from modest gaps in Europe and the United States to a nearly 300-contact difference per 1,000 high-need adults in China. The magnitude and certainty of the gradient differed across cohorts, and the authors stress that heterogeneity itself is informative: health systems are not equally equitable, and the tools to measure that now exist at near-zero cost. As populations age worldwide, monitoring whether care is distributed according to need rather than social position may depend on nothing more sophisticated than asking older adults a question they can answer in a single sentence—and then holding systems accountable for the answer.

Subject of Research: Walking difficulty as a marker of mortality risk, health need, and education-related inequality in healthcare response among older adults across six national aging cohorts.

Article Title: Walking difficulty as a marker of high health need and education-related healthcare response in older adults: a cross-national multicohort study

Article References: Walking difficulty as a marker of high health need and education-related healthcare response in older adults: a cross-national multicohort study. (n.d.). https://doi.org/10.1186/s12916-026-05226-8

Image Credits: AI Generated

DOI: 10.1186/s12916-026-05226-8

Keywords: walking difficulty, older adults, mortality, health equity, multimorbidity, education, healthcare utilization, aging cohorts, unmet need, functional limitation, cross-national study, BMC Medicine