Joyce McWilliams

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CONTEXT Uninsured adults receive less appropriate care and have more adverse health consequences than insured adults. Longitudinal studies would help to more clearly define the effects of health insurance on health care and health. OBJECTIVE To assess the differential effects of gaining Medicare coverage on use of basic clinical services and medications(More)
Within Medicare, the Medicare Advantage program has historically attracted better risks-healthier, lower-cost patients-than has traditional Medicare. The disproportionate enrollment of lower-cost patients and avoidance of higher-cost ones during the 1990s-known as favorable selection-resulted in Medicare's spending more per beneficiary who enrolled in(More)
BACKGROUND Previously uninsured adults who enroll in the Medicare program at the age of 65 years may have greater morbidity, requiring more intensive and costlier care over subsequent years, than they would if they had been previously insured. METHODS We used longitudinal data from the nationally representative Health and Retirement Study to assess(More)
CONTEXT Uninsured near-elderly adults, particularly those with cardiovascular disease or diabetes, experience worse health outcomes than insured adults. However, the health benefits of providing insurance coverage for uninsured adults have not been clearly demonstrated. OBJECTIVE To assess the effect of acquiring Medicare coverage on the health of(More)
Uninsured near-elderly people may be particularly at risk for adverse health outcomes. We compared mortality of a nationally representative cohort of insured and uninsured near-elderly people with stratification by race; income; and the presence of diabetes, hypertension, or heart disease, using propensity-score methods to adjust for numerous(More)
CONTEXT Uninsured adults have less access to recommended care, receive poorer quality of care, and experience worse health outcomes than insured adults do. The potential health benefits of expanding insurance coverage for these adults may provide a strong rationale for reform. However, evidence of the adverse health effects of uninsurance has been largely(More)
The proliferation of Medicare Advantage plans has given Medicare enrollees more choices, but these could be overwhelming for some, especially for those with impaired decision-making capabilities. We analyzed national survey data and linked Medicare enrollment data for the period 2004-07 to examine the effects on enrollment of expanded choices and benefits(More)
IMPORTANCE Fostering accountability in the Medicare Accountable Care Organization (ACO) programs may be challenging because traditional Medicare beneficiaries have unrestricted choice of health care providers, are attributed to ACOs based on utilization, and often receive fragmented care. OBJECTIVE To measure 3 related constructs relevant to ACO(More)
OBJECTIVE/METHODS We used national data from the Medical Expenditure Panel Survey and multivariate linear spline regression models to compare trends in children's health insurance coverage and access to care by income and race/ethnicity during (1998-2002) and after (2002-2006) major expansions of state insurance programs. RESULTS During expansions,(More)
IMPORTANCE Despite the importance of identifying and reducing wasteful health care use, few direct measures of overuse have been developed. Direct measures are appealing because they identify specific services to limit and can characterize low-value care even among the most efficient providers. OBJECTIVES To develop claims-based measures of low-value(More)