Changes in mortality after Massachusetts health care reform: a quasi-experimental study.

BACKGROUND The Massachusetts 2006 health care reform has been called a model for the Affordable Care Act. The law attained near-universal insurance coverage and increased access to care. Its effect on population health is less clear. OBJECTIVE To determine whether the Massachusetts reform was associated with changes in all-cause mortality and mortality from causes amenable to health care. DESIGN Comparison of mortality rates before and after reform in Massachusetts versus a control group with similar demographics and economic conditions. SETTING Changes in mortality rates for adults in Massachusetts counties from 2001 to 2005 (prereform) and 2007 to 2010 (postreform) were compared with changes in a propensity score-defined control group of counties in other states. PARTICIPANTS Adults aged 20 to 64 years in Massachusetts and control group counties. MEASUREMENTS Annual county-level all-cause mortality in age-, sex-, and race-specific cells (n = 146,825) from the Centers for Disease Control and Prevention's Compressed Mortality File. Secondary outcomes were deaths from causes amenable to health care, insurance coverage, access to care, and self-reported health. RESULTS Reform in Massachusetts was associated with a significant decrease in all-cause mortality compared with the control group (-2.9%; P = 0.003, or an absolute decrease of 8.2 deaths per 100,000 adults). Deaths from causes amenable to health care also significantly decreased (-4.5%; P < 0.001). Changes were larger in counties with lower household incomes and higher prereform uninsured rates. Secondary analyses showed significant gains in coverage, access to care, and self-reported health. The number needed to treat was approximately 830 adults gaining health insurance to prevent 1 death per year. LIMITATIONS Nonrandomized design subject to unmeasured confounders. Massachusetts results may not generalize to other states. CONCLUSION Health reform in Massachusetts was associated with significant reductions in all-cause mortality and deaths from causes amenable to health care. PRIMARY FUNDING SOURCE None.