People are still going to specialists, and they're hitting urgent care centers a lot more than they used to. In fact, visits to "alternative venues," including urgent care clinics, rose by 46.9 percent. But for primary care, people are staying away in droves, resulting in "double-digit declines" in visits to PCPs.

The largest declines, according to the study, were among young adults, people who didn't have chronic conditions and residents of low-income areas. In addition, the proportion of adults with no PCP visits in a given year rose from 38.1 percent to 46.4 percent. There was a substantial drop in visits to PCPs for "low-acuity" conditions, while preventive visits did increase—but just by a very small number.

Costs, however, rose even as visits dropped, with the mean out-of-pocket costs paid by insureds rising by nearly a third for problem-based visits and more PCP visits requiring a deductible than they used to.

"There is a lot of data showing that when you raise health care costs, people will receive less care," says Dr. Kimberly Rask, chief data officer at Alliant Health Solutions. "But it doesn't mean that they only stop unnecessary care. They will reduce both necessary and unnecessary care."

The fact that member costs for preventive PCP visits declined by 75 percent likely accounts for the slight increase in the number of those kinds of visits. And regarding the drop in visits to PCPs for actual problems, one report concludes that "this decline may be explained by decreased real or perceived visit needs, financial deterrents, and use of alternative sources of care."

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