PORTLAND, OR — A pilot study in one of the first states to embrace the Affordable Care Act (ACA) shows a significant decline in out-of-hospital cardiac arrests (OHCAs) after rapid health insurance expansion in Oregon[1].
After examining data in more than 550,000 adults, researchers report the incidence of OHCA among those age 45 to 64 years dropped 17%, from 102 per 100,000 before the ACA to 85 per 100,000 after ACA implementation (95% CI 3.7–31; P=0.013).
OHCA rates shifted only slightly, from 275 to 269 per 100,000, among the near-universally insured elderly (>65 years) over the same period, a difference that was not statistically significant (P=0.70).
“A relationship between health insurance expansion and reduced OHCA rates could explain an important portion of the previously observed decreases in all-cause mortality, since OHCA constitutes a large proportion of overall mortality,” lead author Dr Eric Stecker (Oregon Health & Science University, Portland) and colleagues write in the study, published June 28, 2017 in the Journal of the American Heart Association.
Healthcare policy expert Dr J Michael McWilliams (Harvard Medical School, Boston, MA) told theheart.org|Medscape Cardiology in an email that while insurance may very well reduce rates of OHCA, “the reduction in this study seems too good to be true.”
“The populationwide estimate is a 17% reduction, but that would imply an implausibly big reduction among the less than 10% of the population gaining coverage (the effect among those patients gaining coverage would have to be 10 times greater),” he said.
Other factors could be driving the decline in OHCA or it could be noise (ie, limited precision or statistical power), added McWilliams, noting the very wide confidence interval of the estimate.
Emergency-medicine physician Dr Laura Medford-Davis (Baylor College of Medicine, Houston, TX) said, “One thing that strikes me is that cardiac arrest is something where the risk factors may accumulate over a long period of time, so seeing a noticeable decline in just a couple of years is surprising and makes one wonder if a much bigger decline will occur in the future if the results really are related to health-insurance expansion.”
She continued, “The next steps are to replicate the findings across multiple counties in multiple states, including states that did not expand Medicaid, because the biggest limitation is that this is one county, one state.”
One County, One State
Stecker and his colleagues studied OHCA rates during 2011–2012 (preexpansion) and 2014–2015 (postexpansion) among residents of Oregon’s most populous county, Multnomah County, using US Census Bureau data and EMS encounter data for the county. OHCA cases with noncardiac causes (trauma, accident, suicide, overdose, GI bleeding) were excluded.
The middle-aged and elderly population in the county grew from a mean of 274,454 in the preexpansion period to 290,838 in the postexpansion period; OHCA of primary cardiac etiology dipped ever so slightly from 844 to 834 cases.
Medicaid expansion was responsible for the greatest reduction in noninsurance, with coverage jumping abruptly from 7% before the ACA (95% CI 5.5%–8.5%) to 13.5% after the ACA (95% CI 11.5%–15.5%)—representing a 93% relative increase.
Over the same period, direct-purchase insurance increased from 8.2% (95% CI 6.9%–9.5%) to 10% (95% CI 8.5%–11.5%), while employer-sponsored coverage was unchanged.
Expanded insurance coverage could have influenced OHCA through healthcare improvements that promote CVD prevention and prompt CVD diagnosis and management, but a prior study of a randomized Medicaid expansion program in Oregon showed no change in physical-health indicators[2]. The number of patients in that study may have been too small for health systems to improve access, prevention, and disease management activities for new enrollees, Stecker and colleagues suggest.
The investigators detail several potential confounders to their results, including socioeconomic determinants of health, declines in unemployment among the middle-aged between time periods, and insurance-independent improvements in patient- or physician-driven sudden cardiac arrest. Further, the observational pilot study was conducted in a single urban area and was underpowered for regression-based analyses.
“As a result, it should not be used to infer that health insurance was the cause of the observed decline in OHCA incidence nor that the findings would be consistently generalizable to other regions,” the authors write.
An accompanying editorial[3] by nurses Mary Fran Hazinski (Vanderbilt University, Nashville, TN) and Carole R Myers (University of Tennessee, Knoxville) also point out that Oregon was undergoing a massive healthcare payment and delivery innovation when the study was conducted that included establishment of patient-centered primary-care homes with a system of regional coordinated-care organizations that was required to follow evidence-based guidelines and monitor quality of care and cost-effectiveness.
Thus, the findings “may not be generalizable to other states or even to other counties in Oregon,” the editorialists write.
While both the investigators and experts agree the study should spur further research, it also highlights the difficulty of assessing the effects of health insurance on hard clinical outcomes such as blood-pressure control, MI rates, and OHCA, McWilliams said.
This is in part because these events occur infrequently, so data are less available, and study designs that work well for measuring the immediate impact of coverage on access to care, for example, don’t work as well when assessing longer-term benefits that may take years to manifest. And health insurance has never been randomized on a large enough scale to settle the debate.
“When we focus on the lack of consensus evidence on the effects of coverage on hard outcomes like mortality and use that as an argument against covering the uninsured, I think we let perfect be the enemy of good,” he said.
As to whether the new findings could figure in the current debate over the fate of the ACA, he added, “We already have plenty of evidence on the benefits of health insurance to guide evidence-based policy. That is not the problem. The problem is that the evidence is being ignored and mischaracterized by policy makers.”
Stecker reported study support from the National Heart, Lung, and Blood Institute. Disclosures for the coauthors are listed in the paper. Medford-Davis is a consultant for McKinsey & Co. Hazinski is a former consultant to the American Heart Association Emergency Cardiovascular Care programs and in that position received significant compensation. Myers reports no relevant financial relationships.
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