(SACRAMENTO, Calif.) -- People with health insurance are more likely to use preventive services such as flu shots and health screenings to reduce their risk of serious illness, but they are no more likely than people without health insurance to engage in risky health behaviors such as smoking or gaining weight, researchers at UC Davis and University of Rochester have found.
The findings, published in the November-December issue of the Journal of the American Board of Family Medicine, contradict the common concern that expanding health-care coverage may encourage behaviors that increase utilization and costs.
"The notion that people with insurance will exhibit riskier behavior is referred to by economists as 'ex ante moral hazard' and has its roots in the early days of the property insurance industry," said Anthony Jerant, professor of family and community medicine at UC Davis and lead author of the study. "After buying fire insurance, some people wouldn't manage fire hazards on their property. But health care is different. Someone might not care if their insured warehouse burns down, but most people want desperately to avoid illness."
Jerant and his colleagues evaluated respondents in the Medical Expenditure Panel Survey, a source of national data on the costs and uses of health care. They included adults who entered the survey between 2000 and 2008, participated for two years and had insurance at least once during those two years of participation. The team then compared data on 96,021 respondents while they were insured to data on them while they were uninsured.
Specifically, the team compared health behaviors that are often detrimental to health such as smoking, seat belt use and weight gain. They also focused on use of preventive care services that are intended to protect health, including flu vaccinations, colorectal cancer screenings, mammography, pap smears and PSA (prostate-specific antigen) tests. In addition, the researchers examined numbers of office visits, prescriptions and other expenditure metrics.
The results showed that changes in health insurance status were closely linked to preventive care, which increased with coverage and decreased without it. The gain or loss of coverage, however, had no significant relationship to changes in health behaviors. This contradicts a belief long-held by some health economists that mandating the purchase of health insurance coverage may increase risky behavior. While this belief is at odds with the experiences of many physicians, this is the first time the relationship has been vigorously investigated in a national sample of adults of all ages.
"There has been a concern that people would say, 'Hey, I have insurance now, I don't have to worry about my diet. If I get heavy and develop a problem, I can just go to a doctor and have it treated,'" said Jerant. "Empirically, we find that's not the case. Health insurance coverage did not worsen the health habits we studied."
"These results do show that having health insurance affects the likelihood of receiving important preventive services that can potentially reduce the chance of an influenza-related hospitalization or death and prevent or detect colorectal or cervical cancer," said co-author Kevin Fiscella, professor of family medicine at the University of Rochester School of Medicine. "This is a critical message, as many states continue to debate whether to expand Medicaid."
While the results of this study generally support the broad intent behind the Affordable Care Act (ACA) to expand insurance coverage as one means to encourage preventive care, Jerant urges caution.
"The people in our study voluntarily acquired health insurance, while the ACA is mandatory," he said. "We will need to verify whether our findings apply to mandatory coverage. People may behave differently when coverage is mandated."
In addition, the study does not address why gaining insurance improves receipt of preventive care but not health behaviors that can have profound health effects. The authors suggest that this may result from clinicians having a greater vested interest in preventive interventions, which are more directly under the clinicians' control and easier to bring about than sustained lifestyle changes. The authors also point out that studies have found that clinical efforts to encourage weight control, seat belt use and smoking cessation have limited efficacy.
While preventive care increased for those with insurance, that increase was not uniform across different types of care. For example, insurance increased cancer screenings, such as colonoscopies, much more than flu shots. The authors hypothesize this may be due to differences in cost and access, as vaccines are relatively inexpensive for uninsured people to buy and are widely available in many workplaces, drugstores and other places -- not just in health-care facilities
Ultimately, the study findings counter a theoretical barrier to health insurance expansion.
"Now we have empirical evidence that patients don't change the health behaviors we studied as a consequence of changes in their health insurance alone, and we've confirmed that insurance encourages people to get vaccinations and cancer screenings," Jerant said. "In other words, insurance works."
In addition to Jerant and Fiscella, study authors were Daniel Tancredi and senior author Peter Franks of UC Davis. The research had no external funding. A copy of the study is available at https://jabfm.org/content/26/6/759.full.
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