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Beginning September 23, 2010, the dependent coverage expansion in the Affordable Care Act allowed adults younger than 26 years to obtain insurance through their parents. In a JAMA Pediatrics article, Kotagal and colleagues1 concluded that this provision had “limited impact on health and access.” We reassessed this question using the same data set but a larger sample size and different methods.
Our study used deidentified publically available data from the 2005 to 2012 Behavioral Risk Factor Surveillance System and was deemed exempt from review by the Institutional Review Board of the Harvard School of Public Health. Following prior work,2-4 we used a difference in differences approach to compare coverage, health, and access for individuals aged 19 to 25 years (treatment group) and 26 to 34 years (control group).
Outcomes included having any health insurance, self-reported health (excellent/very good/good vs fair/poor), access to a usual source of care, a routine checkup in the past year, and the inability to see a physician in the past year because of cost.
Multivariate linear probability models controlled for a monthly trend; state, year, and calendar month; and an indicator for the enactment period (March 30, 2010-September 22, 2010). The postexpansion period began September 23, 2010. Because economic conditions may have affected coverage rates differentially for younger and older adults, we controlled for state unemployment rates. We also controlled for race/ethnicity, sex, income, marital status, education, employment, and cellular telephone use because cellular telephones were added to the Behavioral Risk Factor Surveillance System in 2011 and the use may have differed by age. Analyses used Behavioral Risk Factor Surveillance System survey weights and accounted for the complex survey design. Two-sided P values less than .05 indicated statistical significance. Analyses were performed with Stata 13 (StataCorp).
The sample (n = 456 966) was 50.5% male and 70.8% white. Group demographics were similar across the intervention and control groups except for marital status and education (Table 1).
Compared with the control group, the dependent coverage provision was associated with an increase of 6.6 percentage points (95% CI, 5.4-7.7) in the probability of insurance coverage among individuals aged 19 to 25 years (P < .001) and a decrease of 0.8 percentage points (95% CI, 0.0-1.6) in fair or poor self-reported health (P = .04). Compared with the control group, the proportion of young adults with a usual source of care increased by 2.4 percentage points (P < .001; 95% CI, 1.1-3.6) while the proportion of young adults unable to see a physician because of cost declined by 1.9 percentage points (P = .001; 95% CI, 0.8-3.0). There was no statistically significant change in the percentage of young adults who reported a routine checkup in the previous year (Table 2). Comparison of trends before 2010 in these outcomes showed no significant differences by age group.
We found that the dependent coverage provision was associated with improved self-reported health and access to health care among young adults aged 19 to 25 years compared with a control group of older adults who experienced worsening coverage and access to care during this period. Another recent analysis of the Behavioral Risk Factor Surveillance System reported that the provision did not significantly affect health and access; however, we found different results primarily owing to increased power from a larger sample. Our findings were consistent with previous evidence from several data sources that the Affordable Care Act’s dependent coverage expansion improved self-reported health and access to care.2,5,6
A key limitation of this study was that any factors changing differentially across time for younger adults vs the control group could have biased our findings; however, our adjustment for additional confounders strengthened our results compared with prior work. Our findings add to the literature on the effect of the dependent coverage expansion and highlight the importance of study design in quasi-experimental analyses.
Corresponding Author: Jacob Wallace, BA, Harvard PhD Program in Health Policy, 14 Story St, Cambridge, MA 02138 (firstname.lastname@example.org).
Published Online: March 2, 2015. doi:10.1001/jamapediatrics.2014.3574.
Author Contributions: Mr Wallace had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Both authors.
Acquisition, analysis, or interpretation of data: Wallace.
Drafting of the manuscript: Wallace.
Critical revision of the manuscript for important intellectual content: Both authors.
Statistical analysis: Both authors.
Study supervision: Sommers.
Conflict of Interest Disclosures: Dr Sommers currently serves as a part-time advisor in the Office of the Assistant Secretary for Planning and Evaluation at the US Department of Health and Human Services.
Funding/Support: This material is based on work supported by grant DGE 1144152 from the National Science Foundation Graduate Research Fellowship (Mr Wallace).
Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Disclaimer: This research letter does not represent the views of the US Department of Health and Human Services.
Wallace J, Sommers BD. Effect of Dependent Coverage Expansion of the Affordable Care Act on Health and Access to Care for Young Adults. JAMA Pediatr. 2015;169(5):495–497. doi:10.1001/jamapediatrics.2014.3574
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