There are several reasons hospitals might want to be in the insurance business, or more closely aligned with insurers. By acting in cooperation, a unified organization might be able to better design incentives for higher-quality care. Or, by combining similar functions like human resources or tech support, the organization might cut costs. A joint provider-insurer may also be better able to adapt to — and make more money from — new Medicare payment models in the Affordable Care Act. Eventually, an organization that combines the functions of health care provision and health care insurance might have a leg up in the market, putting competitors at a disadvantage or driving them out. With less competition, of course, an organization would be in a good position to raise premiums.

Wary of threats to competition and the effects on consumers and patients, health economists and antitrust regulators are watching these market dynamics with a concerned eye.

Last year, with Steve Pizer of Northeastern University and Roger Feldman of the University of Minnesota, in the journal Health Services Research, I published a study that directly related hospital-insurer integration with quality and premiums. We found that insurance plans offered by hospitals charge higher premiums. We also found that such plans are rated to have higher quality by consumers — but that about 70 percent of the additional premium was not attributable to higher quality. We found no evidence that integration is associated with more generous health plan benefits.

To my knowledge, ours is the only study to directly relate hospital-provided insurance with plan quality and premiums. This is in large part because this is a challenging area to investigate. There is no research-ready database of where and when hospitals and insurers unite. We had to collect such data and build our own database. Moreover, historical data on most insurers’ health care products are scattered and incomplete, if they exist at all. For this reason, we studied the private Medicare plan market (Medicare Advantage) for which such data are readily available.

More work needs to be done in this area. Our study showed that integration between hospitals and plans might not be good for consumers, but it is just one study and was based on only one year of data. Additional data collection and analysis would be challenging and costly, but worth the investment given its importance to the future of health care quality and costs.