The report also noted a strengthening trend toward having employees pay a bigger share of the medical costs under their employer-based insurance plans, nearly 20 percent of which now offer only high-deductible plans to workers.
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"We're projecting a very modest increase in the medical cost trend," said Benjamin Isgur, a director of the Health Research Institute.
Medical costs will rise by 6.8 percent in 2015 "as the stronger economy releases pent-up demand for care and services," according to the institute, which based its projection on costs in the large employer insurance market that covers about 150 million people.
That's a small increase from the 6.5 percent medical cost inflation rate PwC had projected for 2014.
After adjustments in the benefits design of insurance plans—particularly due to the trend toward higher deductibles for workers and narrower networks of medical providers covered—the institute said the net growth rate in medical costs should be 4.8 percent in 2015.
Isgur said it remains to be seen if medical cost inflation eventually swings back to the 9-plus percent rates that PwC projected in the years after the 2008 financial meltdown.
"We do think that we are entering a phase of 'new normal,'" he said.
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But while PwC's new medical inflation rate projection remains much lower than those prior rates, it's still significantly higher than the overall 2.1 inflation rate for the entire U.S. economy.
"The fact that health spending continues to outpace [gross domestic product] underscores the need for a focus on productivity, efficiency and better value for purchases," the report said.
Michael Thompson, principal on the Health Research Institute's advisory team, noted that "health care tends to lag as an indicator," which is why the medical cost inflation rate kept decreasing for several years even though the recession had officially ended.