The Long-term Effects of Early-Life Malnutrition: Evidence from the China Great Leap Forward Famine

(with Seonghoon Kim and Belton M. Fleisher).    Health Economics 2017 26(10): 1264-1277.

We report evidence of long‐term adverse health impacts of fetal malnutrition exposure of middle‐aged survivors of the 1959–1961 China Famine using data from the China Health and Retirement Longitudinal Study. We find that fetal exposure to malnutrition has large and long‐lasting impacts on both physical health and cognitive abilities, including the risks of suffering a stroke, physical disabilities in speech, walking and vision, and measures of mental acuity even half a century after the tragic event. Our findings imply that policies and programs that improve the nutritional status of pregnant women yield benefits on the health of a fetus that extend through the life cycle in the form of reduced physical and mental impairment.

Welfare Consequences of Access to Health Insurance for low- and middle-income households: Evidence from New Cooperative Medical Scheme

 Health Economics. 2020 29(3): 337-352.

This study evaluates the welfare benefits of the New Cooperative Medical Scheme (NCMS), the main public health insurance plan for the rural population in China. The findings show that the value of the NCMS to recipients is slightly lower than the government's costs of implementation, ranging from 0.79 to 0.97 per RMB of the resource cost of the NCMS. The estimated moral hazard costs are low compared with the total benefits. It is also estimated that the benefits originating from the NCMS's insurance function only constitute 20% of the total benefits, suggesting a need for higher generosity levels among rural households. Our results shed new light on the welfare effects of access health insurance among low‐ and middle‐income households.

A pragmatic randomized controlled trial of a cardiac hospital-to-home transitional care program in a Singapore academic medical center

(with Chen Yanying, Tan Yijin, Chua Chenzhan, Jefferey Yoo, Thomas Wong, Helen Chen, John Wong, and Philip Phan)
Journal of Patient Safety and Risk Management. Vol. 25(2) 55–66.

Background: Rehospitalizations are common in healthcare. They are costly for hospitals and patients and a substantial percentage are preventable, partly because hospital-to-community transitions are often unmanaged or poorly managed. In this study, we conducted a pragmatic randomized, controlled trial to evaluate the effectiveness of a new nurse–practitioner-led transitional care program called CareHub, piloted in Singapore’s National University Hospital.
Methods: Study population included all eligible cardiac patients admitted between July 2016 and November 2016. Patients were followed for six months post-discharge. Primary outcomes other than emergency department visits were all cardiac-related: number of re-admissions, specialist visits, emergency department visits, and total days readmitted.
Secondary outcomes: variables related to quality of life and transitional care. Regression analyses were used to estimate the intent-to-treat effect of CareHub and explore treatment heterogeneity.
Results: CareHub reduced the mean number of unplanned readmissions by 0.23 (a 39% reduction relative to control mean of 0.60 unplanned readmissions, p<0.05), mean number of all readmissions by 0.20 (31% reduction relative to control mean of 0.63 readmissions, p¼0.10), mean number of total unplanned days in hospital by 2.2 (56% reduction relative to control mean of 4.0 days, p<0.05), mean number of total days in hospital by 2.0 (42% reduction relative to
control mean of 4.3 days, p<0.10). Treatment effects varied by pre-admission health and socio-economic status.
Conclusion: A carefully designed protocolized cardiac hospital-to-home transition program can reduce resource
utilization while improving quality of life.


Working Papers

The Effects of Cash Transfers to Medical Savings Accounts on Healthcare Utilization and Health

Medical savings accounts are personal savings accounts used only for healthcare service. This study examines the effects of cash transfers to medical savings accounts on healthcare utilization and health by evaluating the 5-Year Medisave Top-up Plan in Singapore, which provides SGD 100 or 200 to all citizens born between 1950 and 1959. We infer the causal effects by comparing the outcomes of individuals born right before and after the program’s cut-off birth date of December 31, 1959. Using monthly longitudinal data from the Singapore Life Panel, the study finds that cash transfers to medical savings accounts leads to a 13.7% increase in the probability of individuals going in for positive prescription medication spending. Further, consistent with liquidity constraints, the responses are larger for individuals with low liquid assets or low credit access.

How do Age-related Policy Reforms Promote Elderly Employment in Singapore?
(with Emiko Usui)

This paper uses data from the Singapore Life Panel to investigate the effects of age-related policy reforms on elderly labour supply behaviours in Singapore. We first evaluate the impact of the 2017 revision of the Retirement and Re-employment Act (RRA), which raised the maximum re-employment age from 65 to 67, for the cohort in which the individuals were able to begin drawing a pension at age 64. We find that the RRA revision reduced the probability of unemployment among people aged 66 by 5.8 percentage points and increased their chances of staying in the longest-held job of their lifetime by 10.3 percentage points. We then examine the impact of the 2018 pension reform which raises the pension-eligibility age from 64 to 65, for the cohort in which the individuals were offered re-employment up to the age of 67. This increase in the pension-eligibility age increased the probability of full-time work among people aged 64 by 8.2 percentage points and reduced the probability of part-time work by 5.7 percentage points. These two reforms promoted elderly employment in different ways. Specifically, enhanced employment protection at age 66 increased the elderly’s labour supply in the extensive margin, which resulted in a welfare improvement for the elderly since the elderly who had been underemployed were less likely to be so after the reform; in contrast, their ineligibility to claim their pension at age 64 lowered the elderly’s economic well-being since they increased their labour supply in the intensive margin to supplement the delayed pension benefits.

Urban-Rural Differences in Hospital Quality of Care: Evidence from Patients with Acute Myocardial Infarction in China
(with Ding Tao)


Objective. To determine the effect of initial admission to rural hospitals on mortality for patients with AMI in China.

Design. We used the 2013 to 2017 medical record data in Shanxi China, including 80,650 residents aged 18 years or older hospitalized with a principal diagnosis of acute myocardial infarction in 144 hospitals categorized rural or urban. We used the differential distance between patients’ residence to the nearest hospital and the nearest reperfusion hospital as instrumental variables to account for the nonrandom selection of patients into hospitals.

Main Outcomes and Measures. The primary outcome was in-hospital mortality. Secondary outcomes included length of stay and treatments.

Results. Unadjusted and risk-adjusted mortality rates using logistic regression models indicated no significant differences between urban and rural hospitals. However, patients who initially admitted to rural and urban hospitals differed in observable and unobservable characteristics. Analyses indicated that the traditional logistic regression models were possibly confounded by unmeasured patient factors. When the same data were analyzed with the instrumental variable technique, mortality rates at rural hospitals are significantly higher than those in urban hospitals. Further analyses of treatment choices show that the disparities in treatments are significant between urban and rural hospitals.

Conclusions. Being admitted to rural hospitals for AMI patients leads to higher in-hospital mortality, suggesting significantly worse quality of care in rural hospitals in China. More efforts should be made to address the identified gap, particularly in terms of hospital facility and reperfusion therapy. Given the rapid aging trend and the vast population residing in rural regions, this mission is both urgent and essential for China policy makers.