J. Michael McWilliams*

J. Michael McWilliams*

Warren Alpert Foundation Professor of Health Care Policy and of Medicine, Harvard Medical School
*Harvard PhD Program in Health Policy Alumnus & Faculty Member

Dissertation Title:  "Effects of Insurance Coverage on Health Services, Outcomes, and Disparities among Adults with Cardiovascular Disease and Diabetes"

Previously uninsured adults who enroll in the Medicare program may have greater morbidity, requiring costlier care over subsequent years than they would if previously insured.

In the first paper, propensity-score methods were used to compare self-reported health-care utilization and expenditures longitudinally from ages 55-72 for adults who were privately insured or uninsured before 65. Previously uninsured adults with cardiovascular disease or diabetes reported significantly greater use of services and higher total medical expenditures after age 65 than previously insured adults who were otherwise similar at age 59-60. Therefore, the costs of expanding coverage for uninsured near-elderly adults may be partially offset by subsequent reductions in health-care utilization and spending after age 65. Uninsured near-elderly adults experience worse health outcomes than insured adults. However, the health benefits of providing insurance coverage for uninsured adults have not been clearly demonstrated.

In the second paper, quasi-experimental analyses of longitudinal survey data were conducted to assess the effects of acquiring Medicare coverage on the health of previously uninsured adults. Relative to previously insured adults, previously uninsured adults, particularly those with cardiovascular disease or diabetes, reported significantly improved health trends after age 65 for a summary health measure and many component measures. Therefore, providing earlier health insurance coverage for uninsured adults with these conditions may considerably improve their health outcomes. Efforts to improve management of cardiovascular disease and diabetes may or may not reduce disparities in clinical outcomes. Furthermore, the effects of Medicare coverage on these health disparities have not been conclusively demonstrated.

In the third paper, serial cross-sectional data were used to assess recent national trends in disease control, trends in disparities in control, and changes in disparities after age 65 associated with near-universal Medicare coverage. Control of blood pressure, glucose, and cholesterol improved substantially since 1999, but racial, ethnic, and educational disparities persisted or widened, suggesting more focused efforts are needed to improve quality of care for disadvantaged groups. Where present, group differences in systolic blood pressure, HbA1c, and total cholesterol were smaller for ages 65-85 than ages 40-64. Thus, expanding insurance coverage before age 65 may reduce disparities in important health outcomes.


Graduation Year