Insurers paid out a total of about $1.5 billion in consumer rebates from 2011 to 2012 for not meeting the medical lost ratio requirement, which sets a strict formula for keeping overhead costs low compared to medical benefits paid out. The rationale for the rule is to ensure that peoples' premium payments be used mostly for actual health-care claims.
In addition to that, insurers reduced overhead by a total of about $1.75 billion in the same time period without increasing their profit margin, the Commonwealth Fund report said.
At the same time, the medical loss ratio requirement has not lead to significantly reduced competition among insurers, the Commonwealth Fund report found.
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"The Affordable Care Act has changed how health insurance is bought, sold and managed, and, on balance, those changes have produced substantial benefits for consumers without harming insurance markets," said Michael McCue, a Virginia Commonwealth University researcher who was the lead author of the Commonwealth Fund report.
"In its first two years, the MLR requirement contributed to significant reduction in insurance administration costs, a major source of health-care cost growth in the United States," said McCue, whose report relied mainly on data from the Centers for Medicare and Medicaid Services.
However, McCue told CNBC that the success of the requirement could lead in coming years to accelerated consolidation of the health insurance industry, since profit margins will become tighter. That, in turn, could decrease competition in the market.
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There were other criticisms as well.
"The medical loss ratio requirement does nothing to address the main drivers of health-care costs and puts an arbitrary cap on what health plans spend on a variety of programs and services that improve the quality and safety of patient care," said Clare Krusing, a spokeswoman for health insurance industry group, America's Health Insurance Plans. "Moreover, the health care reform law's $100 billion health insurance tax will cause premium increases that exceed the value of prospective rebates."
Indeed, McCue's research found that insurers were still spending relatively little on initiatives that could improve the quality of care for their customers, despite the fact that they receive credit for such spending in the MLR formula, and that it can help hold down costs from health claims.
Insurers spent an average of just 1 percent of their premiums on so-called quality improvements, which can include programs toe prevent hospital re-admissions, improve patient safety, and increase overall wellness.