Despite advances in healthcare delivery, access to high-quality medical care remains uneven in many countries. In systems where medical resources are limited and physician quality varies widely, patients must make important decisions about where and from whom to seek care. These choices can shape not only individual health outcomes but also the efficiency of healthcare systems.

Yuli Xu, a postdoctoral fellow at APARC’s Asia Health Policy Program, has made these questions central to her research on how institutional structures shape individual behavior and inequality in labor and health markets in both China and the United States. “I examine how policy reforms and institutional arrangements influence outcomes for families, workers, and patients, using large administrative and survey datasets,” she says

At a recent webinar, Xu presented new research examining patients’ preferences for physician continuity in China’s healthcare system. Her work explores whether patients prefer to return to the same physician even when institutional barriers to switching providers are minimal.

Watch her talk on our YouTube channel.
 

Physician Continuity in a Flexible Healthcare System

Much of the existing research on physician continuity focuses on healthcare systems in developed countries, where institutional rules strongly shape patient behavior. In those settings, referral requirements, insurance networks, and primary care gatekeeping often limit patients’ ability to switch doctors easily.

China’s healthcare system offers a very different context. “My interest in this topic was initially motivated by observing the stark differences between healthcare systems in China and the United States,” Xu says.

“In China, patients can often choose doctors directly with relatively few formal barriers, while high-quality medical resources remain scarce,” she explains. “This contrast made me interested in understanding how patients value continuity of care in a setting with fewer institutional switching frictions but greater variation in physician quality.”

Patients in China can often select physicians directly through hospital appointment systems and may visit specialists without referrals. This flexibility allows researchers to observe patient preferences more clearly, since continuity with a physician is less likely to be driven by institutional constraints.

Xu’s study draws on administrative medical claims data from residents enrolled in China’s Urban and Rural Resident Basic Medical Insurance program. The dataset includes detailed information on outpatient visits, diagnoses, expenditures, and physician identifiers. These records make it possible to track how patients choose physicians over time and whether they repeatedly return to the same doctor.

Evidence of Persistent Physician Choice

Xu’s first question is whether patients maintain consistent relationships with physicians when switching is easy. The data show that many do. Patients with chronic conditions frequently return to the same physician over multiple visits, suggesting that continuity of care remains an important factor in medical decision-making.

To analyze physician choice more systematically, Xu estimates a discrete choice model that examines how patients weigh factors such as physician experience, consultation fees, and prior interactions with the doctor.

The results reveal that prior relationships strongly influence patient decisions. Patients are significantly more likely to return to physicians they have visited in the previous six months.

The study also finds variation in preferences across patient groups. Female patients and patients with lower socioeconomic status are more likely to maintain long-term relationships with physicians. At the same time, patients respond to financial incentives. Higher consultation fees reduce the probability of selecting a physician.

These findings suggest that even in a flexible system where patients can easily switch providers, many still value stable relationships with physicians.

To estimate the causal value of physician continuity, Xu examines what happens when these patient-physician relationships are unexpectedly interrupted.

The results show clear behavioral changes. When their regular physician is absent, patients reduce visits to that department and spend less on medical care. The decline extends beyond the physician’s own department. Patients also reduce visits to other departments within the same hospital.

This pattern suggests that many patients organize multiple appointments during a single hospital visit. If a trusted physician is unavailable, patients may delay or cancel other appointments. The study also finds little evidence that patients compensate by seeking care at other hospitals. Instead, many appear to postpone care until their regular physician returns.

Implications for Healthcare Utilization and Policy

By examining how patients navigate healthcare systems with limited resources and flexible provider choice, Xu’s research offers new insights into how institutional design shapes healthcare access and efficiency.

While Xu finds no evidence of worsening short-term health outcomes within months after physicians’ absence, the research indicates that physician continuity can reduce costs for certain patients. Individuals with more severe conditions incur higher medical spending when they must see unfamiliar physicians, suggesting that established relationships may improve efficiency by facilitating information sharing and familiarity with medical histories.

“One strand of my work during my postdoc focuses on the Chinese healthcare system, where medical resources, especially high-quality physicians, are scarce and unevenly distributed,” Xu notes.

Her findings highlight the importance of stable patient-physician relationships in healthcare systems where provider quality varies. Even when patients have the freedom to choose among providers, many still demonstrate strong preferences for continuity with trusted physicians.

Research Community and Future Directions

Xu says her time at APARC has played an important role in advancing this research. “My time at APARC has provided an incredibly supportive and stimulating research environment,” she says. She credits the guidance of Karen Eggleston, director of the Asia Health Policy Program, whose expertise in health economics and Asian health systems helped shape the project.

She also highlights the broader intellectual community at Stanford. “I have had the opportunity to connect with many wonderful scholars across the Freeman Spogli Institute and Stanford more broadly,” Xu says, noting that conversations with economists and health policy researchers have helped refine her work and expand her perspective on healthcare systems.

Looking ahead, Xu plans to continue studying healthcare systems across different institutional settings. “I would encourage young scholars not to focus on only one country, but instead to study broader research questions and examine how they play out across different institutional settings,” she says. “Comparing institutions across countries can generate new insights and help identify mechanisms that might not be visible in a single context.”
 

Key Takeaways
 

• Patients in China demonstrate strong preferences for continuity with physicians despite minimal institutional barriers to switching providers.

• Physician absences lead to significant reductions in healthcare utilization within the same department and across other departments in the same hospital.

• Patients do not substitute toward other hospitals when their regular physician is unavailable, and many return to their original physician once they resume practice.

• The findings suggest that stable patient-physician relationships can improve efficiency and reduce costs in healthcare systems with flexible provider choice.

Addressing Inequalities in Health Care

Liang’s summer medical school project examined the prevalence of receiving annual eye screenings among South Korean adult patients with type 2 diabetes and how access to that care differed across demographic and socioeconomic groups over time. The goal was to investigate why screening rates for diabetic retinopathy, a complication of type 2 diabetes, remain low in South Korea, despite the country having universal health insurance coverage and guidelines that recommend annual eye screenings to prevent this leading cause of blindness.

He worked on this project with co-advisors Eggleston and Young Kyung Do, a professor in Seoul National University’s Department of Health Policy and Management and AHPP’s inaugural postdoctoral fellow. They found that lower-income patients with diabetes experienced barriers to quality diabetes care and had lower access to annual diabetes-related eye screenings.

For Liang, these results underscored a deeper lesson: even strong health systems with universal health insurance coverage have structural socioeconomic inequities that leave vulnerable groups behind. The findings helped solidify his conviction that improving health care requires more than clinical training alone. 

The project culminated in Liang’s presentation of the findings at the 2021 AcademyHealth Annual Research Meeting and spurred a new sense of purpose. ”It grew into a life-changing journey at Stanford,” Liang says.

That journey has led him to collaborate with researchers from around the world, particularly in Japan, Korea, and China, utilizing large-scale data to advance population health and applying population health methods to research topics ranging from maternal and child health to mental health, aging, and inflammatory skin diseases.

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Liang in South Korea. Photo courtesy of Richard Liang.

From Research to Health Policy Impact

Over the years, Liang evolved from a mentee of Eggleston into a collaborator on projects in Korea and elsewhere. As COVID-19 disrupted health services worldwide, he joined Eggleston and a team of researchers in studying the impact of the pandemic on chronic disease care in India, China, Hong Kong, Korea, and Vietnam. Their findings showed that marginalized and rural communities in those countries were hit especially hard, with negative consequences for population health that reached far beyond those directly infected with the virus.

He and Eggleston also co-authored a study on preferences for telemedicine services among patients with diabetes and hypertension in South Korea during the early COVID-19 pandemic. The research drew the attention of the Prime Minister’s Office in Korea, which used it to guide national policy on telemedicine, a field still lacking a formal legal framework in the country.

For Liang, it was proof of the available opportunities to make tangible improvements in population health by combining rigorous research with policy engagement and drawing on insights across medicine, public health, and the social sciences.

“As a medical student researcher with experiences across different East Asian countries, I witnessed firsthand many pressing challenges in health and society, from rapidly aging populations to rising rates of chronic diseases,” he says. “To tackle these issues holistically, there is a growing need to bring together diverse perspectives, but regional collaborations in medical and public health research have been scarce, and rarer still between the biomedical and social sciences.”

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Liang in China on a field visit during a 2025 summer seminar co-taught by Professors Eggleston and Williams. Photo courtesy of Richard Liang.

A Second Academic Home

Eggleston describes Liang as a model of interdisciplinary scholarship. In addition to medical school and doctoral research, he has carved out space to pursue his passion for East Asian studies. He has taken classes with APARC and affiliated faculty on topics ranging from health and politics in modern China to historical and cultural perspectives on North Korea, science and literature in East Asia, and tech policy, innovation, and startup ecosystems in Silicon Valley and Japan.

“The various classes and seminars I’ve attended through APARC, and subsequently as an East Asian Studies master’s student, have helped me think more critically about how the science and practice of medicine impact policy and society, and vice versa,” Liang says. Thanks to these experiences, he also found “a second academic home away from the medical school — a community that shares the recognition of the need to strengthen dialogue and cooperation across the Pacific and that actively encourages the interdisciplinary environment necessary to make my aspirations a reality.”

Most recently, he participated in a summer seminar on AI-enabled global public health and population health management, co-taught by Eggleston and Michelle Williams, a professor of epidemiology and population health at Stanford’s School of Medicine. Offered via the Stanford Center at Peking University, this three-week seminar focused on advancing global health through cross-cultural collaboration and the application of cutting-edge technology in population health and health policy decision-making. 

“During this program, I not only got to share my experiences from conducting population health research across East Asia, but also learn from and alongside fellow students across different disciplines, spanning from international relations to computer science,” Liang notes. He especially enjoyed meeting local Chinese graduate students and providing feedback and near-peer mentorship as an upper-year graduate student.

The seminar also led to exploring additional opportunities for research collaborations to study the implications of long-term annual health screenings across China. Liang, Eggleston, and Williams plan to expand this collaborative work.

Preparing to Become a Better Care Provider

Liang’s work across borders and disciplines not only advances research but also deepens the perspective of cultural humility he brings to his future role as a physician.

“The cross-cultural experiences and fruitful academic exchanges I’ve learned through as a Stanford graduate student not only inform my research in different countries, but also help prepare me to become a better care provider for my future patients,” he says.

For his achievements, Liang has earned multiple honors, including a Young Investigator Collegiality Award from the International and Japanese Societies for Investigative Dermatology, the Critical Language Scholarship in Korean from the U.S. Department of State, and the Stanford Center for Asian Health Research and Education Seed Grant.

He is looking forward to finishing medical school, attending a residency program, and continuing an interdisciplinary career that advances human health and well-being.

Reflecting on the fleeting nature of student life, his advice to fellow students is to remember that “Your time as a Stanford student can really fly by, so make sure to explore the opportunities that speak to you and offerings across the university, by organizations like APARC and the Freeman Spogli Institute for International Studies. The Bechtel International Center’s Office of Global Scholarships and the Hume Center for Writing and Speaking are also wonderful resources to get started.”

It is advice he has embodied himself, building a career at the intersection of medicine, public health, and East Asian studies, one project at a time.

The Walter H. Shorenstein Asia-Pacific Research Center (APARC) is pleased to invite applications for a suite of fellowships in contemporary Asia studies to begin in fall quarter 2026.

The Center offers postdoctoral fellowships that promote multidisciplinary research on Asia health policy, contemporary Japan, and contemporary Asia broadly defined, as well as postdoctoral fellowships and visiting scholar positions with the Stanford Next Asia Policy Lab and a visiting fellow position on contemporary Taiwan. Learn more about each opportunity and its specific application requirements:

2026-27 Asia Health Policy Program Postdoctoral Fellowship

Hosted by the Asia Health Policy Program at APARC, the fellowship is awarded to one recent PhD recipient undertaking original research on contemporary health or healthcare policy of high relevance to countries in the Asia-Pacific region, especially developing countries. Appointments are for one year beginning in fall quarter 2026. The application deadline is December 1, 2025.

2026-27 Japan Program Postdoctoral Fellowship

Hosted by the Japan Program at APARC, the fellowship supports research on contemporary Japan in a broad range of disciplines, including political science, economics, sociology, law, policy studies, and international relations. Appointments are for one year beginning in fall quarter 2026. The application deadline is December 1, 2025.  

2026-27 Shorenstein Postdoctoral Fellowship on Contemporary Asia

APARC offers two postdoctoral fellowship positions to junior scholars for research and writing on contemporary Asia. The primary research areas focus on political, economic, or social change in the Asia-Pacific region (including Northeast, Southeast, and South Asia), or international relations and international political economy in the region. Appointments are for one year beginning in fall quarter 2026. The application deadline is December 1, 2025. 
 

2026-27 Taiwan Program Visiting Fellowship

Hosted by the Taiwan Program at APARC, the fellowship is awarded to one mid-career to senior-level expert with extensive experience studying contemporary Taiwan. The fellowship research focus is on issues related to how Taiwan can meet the challenges and opportunities of economic, social, technological, environmental, and institutional adaptation in the coming decades, using a variety of disciplines, including the social sciences, public policy, and business. The application deadline is March 1, 2026.  
 

As countries confront rising health care spending, policymakers everywhere face a key question: Who benefits from these spending increases?

Consider South Korea, a nation that has sharply increased its per capita health care spending over the past decade, delivering reasonable value in improving health outcomes as measured by rising life expectancy and a reduced overall disease burden. Yet, not all South Koreans reap equal rewards from the country’s health investments, according to a new study. Rather, adults in the lowest-income quintile receive the least health gains for every dollar spent on their care.

Published in the journal Health Affairs Scholar, the study reveals stark income-based disparities in the value of health care — defined as health gains relative to spending — among South Korean adults. The research systematically quantifies how efficiently health spending translates into longer, healthier lives across income groups in South Korea, providing insights into the distribution of health gains relative to health care spending.

“While earlier research often examined disparities in access, utilization, or outcomes separately, our analysis provides a more integrated assessment by jointly examining health care costs and health gains,” explains the research team, including Stanford health economist Karen Eggleston, the director of the Asia Health Policy Program (AHPP) at APARC. Eggleston’s co-authors are Sungchul Park, an associate professor in Korea University’s Department of Health Policy and Management; Young Kyung Do, a professor in Seoul National University’s Department of Health Policy and Management and AHPP’s inaugural postdoctoral fellow; and David Cutler, the Otto Eckstein Professor of Applied Economics at Harvard University. 

Their findings are sobering: between 2010 and 2018, South Korean adults in the lowest income quintile derived the least value from increased health spending compared to those in the middle- and higher income quintiles, suggesting a system that underserves the poorest population.

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Poorer Health, Smaller Gains

Between 2010 and 2019, per capita health care spending in Korea increased from $1,211 to $1,903, growing nearly 6 percent annually. During that decade, life expectancy climbed from 80.5 to 83.7 years, while disability-adjusted life years – expressed as the number of years lost due to ill-health – declined significantly. These measures seemingly suggest health spending has yielded solid returns in terms of improved health outcomes.

Yet stark income inequality persists in Korea. The country has both the highest old-age poverty rate and the largest share of out-of-pocket medical expenses among OECD countries. Does rising health spending benefit all segments of society equally?

To answer this question, the researchers analyzed trends in health spending and outcomes across income quintiles (excluding the bottom 10 percent of the household income distribution) from 2010 to 2018.

They measured health care spending as total medical expenditures, including costs for inpatient and outpatient services, emergency services, and prescription medications. All spending measures were adjusted for inflation and are reported in 2021 US dollars. To asses health outcomes, they used three indicators: (1) health-related quality of life, which relies on standard questionnaires to measure individuals’ perceived physical and mental health over time; (2) life expectancy, calculated using life table methods based on enrollment data from the national health insurance system; and (3) quality-adjusted life expectancy (QALE) at age 25, a measure that reflects both longevity and the quality of life during those years – an essential consideration when evaluating the effectiveness and equity of health care systems. To quantify the value of health care across income groups, the researchers applied statistical methods.

They found that adults in the lowest-income quintile experienced the smallest relative improvement in QALE over time: an increase of 0.7 years, compared with 1.4 years in the second and third quintiles, 1.3 years in the fourth, and 1.2 years in the highest quintile. Translated into a value estimate, adults in the lowest income quintile incurred $78,209 per QALE; in contrast, adults in the second through highest income quintiles achieved greater value estimates of $47,831, $46,905, $31,757, and $53,889, respectively. Thus, the most efficient gains in both longevity and quality of life were in the middle-income groups.

“We found that per capita spending was similar across income groups, but the lowest-income quintile experienced much smaller gains in QALE,” Eggleston and her collaborators write. 

Reflecting the principle of diminishing returns, “these findings highlight structural inequities in the South Korean health system and emphasize the need for targeted policies to promote equitable health care value.” 

Why Spending Does Not Equal Value

While the study did not identify causal pathways, secondary data suggest two plausible explanations for the results: poorer baseline health and greater unmet needs.

The data indicate that adults in the lowest-income quintile had significantly higher rates of chronic disease, disability, behavioral risk factors such as smoking and obesity rates, and mental health issues. These factors make it more difficult to achieve health gains.

Moreover, adults in the lowest-income quintile were less likely to receive preventive services, with markedly lower rates of medical checkups and cancer screenings. “Despite greater health needs, these adults faced persistent barriers to accessing care, particularly financial constraints,” the researchers say.

Notably, the highest value of health spending was not observed among adults in the highest-income group. One explanation is that this group may consume more low-value or marginally beneficial health services.

Policy Implications: Efficiency with Equity

Eggleston and her co-authors emphasize “the need for health policy in South Korea to prioritize both equity and value.” They highlight the following targeted strategies to improve efficiency and fairness:

• Invest in high-value services that link spending to meaningful health outcomes:
  • Improve access to high-value preventive and primary care services by expanding financial protections, particularly for lower-income groups.
  • Improve overall system efficiency by reducing the overuse of low-value health care services.
• Pair health care reform with broader social policies: Coordinate efforts to address upstream factors tied to health disparities, such as income inequality.
• Aim for improvements across the entire population: Implement evidence-based clinical appropriateness guidelines to ensure health care spending yields meaningful and equitable results.

While focused on South Korea, the study’s findings illuminate how income inequality interacts with health system designs and carry lessons for other countries.

“In countries with greater income inequality and fragmented health systems, such as the United States, disparities in health care value may be even more pronounced,” the co-authors write.

As South Korea and other countries continue to invest heavily in health care, the study highlights the urgency of improving the distribution and impact of that increased spending. Without focused reforms, it risks entrenching existing inequities rather than alleviating them.

Over the past two decades, China has pursued an ambitious plan to establish an accessible and affordable health system that meets the needs of its population. As part of this journey, China’s leadership implemented comprehensive health system reforms and achieved near-universal health insurance coverage at a relatively low per capita income level. Key to this process was the integration of rural and urban resident health insurance programs, which has proven to yield positive outcomes in health care utilization, physical health, and related equity issues. Thus far, however, the integration’s potential psychological effects have been understudied.

New research, published in the journal Health & Social Care in the Community, addresses this gap in the literature. The researchers – Stanford health economist Karen Eggleston, the director of APARC’s Asia Health Policy Program (AHPP); Peking University’s Gordon Liu; and Renmin University of China’s Yue-Hui Yu and Qin Zhou, the latter a former visiting scholar with AHPP – find that the urban-rural health insurance integration has been beneficial for improving mental health among China’s rural adults.

Their study underscores the potential of policy-driven health system reforms to address longstanding disparities, promote mental well-being in vulnerable communities, and enhance quality of life among aging populations. This is the researchers’ final installment in a series of studies on China’s urban-rural health insurance integration.

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• Learn more about Dr. Eggleston's related research project, "Addressing Health Disparities in China" > 

Tracking Mental Health Over Eight Years

For decades, China had a fragmented health insurance system, which led to disparities between different populations and hindered the implementation of the Healthy China 2030 blueprint, a bold national strategy to make public health a precondition for all future economic and social development. Responding to this challenge, in 2016, China announced plans to unify its rural and urban health insurance programs. The unified health insurance system, called Urban and Rural Residents’ Basic Medical Insurance (URRBMI), offered equal health service packages and insurance benefits to rural and urban residents. Studies have shown that the integrated system improved healthcare access for nearly 800 million rural residents and helped reduce coverage gaps and inequality. Yet evidence about the integration’s potential psychological impacts has been limited.

Eggleston and her co-authors hypothesized that this reform might also benefit rural adults’ psychological well-being. To test this hypothesis, the researchers conducted a comprehensive analysis using data from the China Health and Retirement Longitudinal Study (CHARLS), a nationally representative survey that tracks health, economic, and social variables among Chinese adults aged 45 and older. The study focused specifically on rural residents, examining changes in mental health, particularly depressive symptoms, before and after the insurance integration. Data from four waves of CHARLS, spanning from 2011 to 2018, allowed the team to analyze trends over a substantial period.

The researchers used an event study combined with a time-varying difference-in-differences (DID) approach, capturing the effect of the health insurance integration on depressive symptoms and comparing changes over time between those affected by the reform and a control group not yet impacted (since local governments introduced the integration reforms in different years, samples in the control group had constantly entered the treatment group during the survey period). This method helps isolate the effect of the policy from other confounding factors, providing a clearer picture of causality. The researchers further examined the heterogeneity of the integration effect across subgroups by gender, age, health status, and family economic status. They also analyzed possible mechanisms through which the reform produced psychological effects

Key Findings: A Significant Drop in Depression

The researchers find that the health insurance integration was associated with a measurable reduction in depressive symptoms among rural seniors. Specifically:

• CES-D scores – a standard measure of depression severity (using a version of the Centre for Epidemiological Studies Depression Scale) – decreased by an average of 0.441 points among those covered by the reform.
• The likelihood of experiencing depression dropped by approximately 3.5% in the post-reform period.
• The decline in depression scores following the integration was continuous, suggesting cumulative effects of the reform. Notably, some psychological benefits appeared up to two years before the reform took effect, likely due to public awareness and positive expectations generated by advance announcements from local authorities.

The results were statistically significant, indicating that the health insurance integration reform has significantly improved the mental health of rural adults and reduced their risk of becoming depressed.

The findings also indicate that a key driver that produced continuous positive psychological effects was the integration’s reduction of health care costs for rural residents, particularly for hospital care. By lowering financial barriers to treatment, the integration improved access to healthcare and made its use more equitable. This, in turn, boosted rural adults’ satisfaction with their health and overall sense of well-being. The improvement may have set off a positive cycle, encouraging more social engagement and physical activity, which helped further ease symptoms of depression.

While the reform reduced depressive symptoms for both male and female older adults, the findings revealed differences across subgroups. It appears the reform did not significantly reduce depressive symptoms for those aged 40-49 and over 70, individuals in poor health, or those in the lowest economic bracket. The researchers attribute this to ongoing financial barriers and limited insurance financing, which may blunt the perceived benefits for high-need groups.

Policy Implications: A Path Toward Health Equity

The study’s co-authors highlight several policy implications for China:

• Expand and standardize coverage: Build on the success of the URRBMI by moving from local-level integration to broader provincial or national coverage, and encourage enrollment among vulnerable populations through subsidies.
• Improve equity for high-need groups: Design more targeted insurance policies for older adults, those with chronic illnesses or disabilities, and low-income groups, especially by covering outpatient treatments for high-cost conditions.
• Increase funding for the URRBMI: Despite progress, reimbursement rates remain low, highlighting the need for greater investment in the program.
• Strengthen rural health infrastructure: Insurance reforms must be paired with improvements in rural healthcare facilities and services to ensure quality care is both accessible and effective.

China’s experience offers valuable lessons for countries aiming to achieve universal health coverage and those grappling with health disparities and aging populations. The positive association between insurance integration and mental health among rural adults in China underscores the importance of comprehensive, inclusive policies addressing financial and social determinants of health.

The study’s findings highlight the need to ensure that the most vulnerable populations benefit equally from health reforms. They also serve as a compelling reminder that thoughtfully designed and implemented reforms can improve physical health and increase mental resilience and social cohesion.