Trends of lack of health insurance among US adults aged 18-64 years: findings from the Behavioral Risk Factor Surveillance System, 1993-2014.

OBJECTIVE To examine the prevalence of lack of health insurance and its changes over time among adult residents (aged 18-64 years) in 50 states and the District of Columbia (DC). STUDY DESIGN Cross-sectional surveys. METHODS We aggregated annual state-based Behavioral Risk Factor Surveillance System (BRFSS) data from 1993 through 2014 to provide nationwide and state-based prevalence estimates for lack of insurance among adults aged 18-64 years. The adjusted prevalence was estimated using log-linear regression analyses with a robust variance estimator after controlling for demographic variables. The trend was assessed separately for the periods 1993-2010 and 2011-2014 due to methodologic changes in the BRFSS. RESULTS From 1993 through 2010, the adjusted prevalence of lack of health insurance increased by 0.54% (P < 0.0001) annually (range: 16.3% in 1995 to 19.1% in 2005); this prevalence decreased significantly in 2014 (15.1%). In 2014, Georgia, Mississippi, and Texas had the highest adjusted prevalences (range: 23.0-24.6%) of lack of health insurance, and DC, Massachusetts, and Rhode Island had the lowest (range: 6.2-10.1%). The changes in the prevalence of lack of insurance over time varied significantly by state. CONCLUSIONS The nationwide prevalence of lack of health insurance decreased significantly in the past few years, especially in 2014 when about one-seventh of Americans aged 18-64 years reported lack of health insurance coverage. The huge variations in the prevalence of lack of health insurance and its changes over time among states suggest continuing efforts to ensure healthcare access for all Americans are needed to improve the overall health of the population.