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.