The researchers did not estimate how many of the newly insured have private coverage. (AP photo/J. Scott Applewhite)

The Patient Protection and Affordable Care Act (PPACA) health coverage access expansion programs helped reduce the percentage of U.S. adults who were uninsured to about 16.3 percent in the second quarter, from about 21 percent in September 2013. 

Dr. Benjamin Sommers — a Harvard University health economist who advises the U.S. Department of Health and Human Services (HHS) — and colleagues come to that conclusion in an analysis published in the New England Journal of Medicine.

The PPACA health insurance exchange program and Medicaid expansion program may have helped 10.3 million adults get health coverage, with the actual increase ranging from between 7.3 million to 17.2 million, the researchers say. The researchers say they believe the programs also helped many children get coverage.

The researchers found the most dramatic results in the uninsured rates for adults with incomes from 139 percent to 400 percent of the federal poverty level, who were eligible for PPACA exchange plan subsidies. In states without Medicaid expansion, the uninsured rate for those middle-income adults fell to about 15.5 percent in the second quarter, from 21 percent in September — before the start of the PPACA exchange individual coverage enrollment period.

In states that used PPACA money to expand access to Medicaid for childless adults, the uninsured rate for middle-income adults fell to 9.6 percent, from 18.6 percent.

Sommers and his colleagues used private survey data to come up with those figures. They did not look at the effects of PPACA on the likelihood that children would have coverage, and they did not distinguish between people who became insured through Medicaid and other government programs and those who obtained commercial health coverage, either through a PPACA public exchange or outside the exchange system.

See also: Gallup: Private insurance may have expanded, too

The Congressional Budget Office has estimated that the net cost of the PPACA exchange program, PPACA Medicaid and Children’s Health Insurance Program (CHIP) expansion, and PPACA small employer tax credits will be $36 billion this year. The Sommers figures suggest that the government may be spending an average about $2,000 to $5,000 this year per newly insured adult as a result of PPACA. Adding the number of newly insured children calculations could reduce those averages substantially.

When Congress was designing PPACA, a number of researchers and think tanks tried to analyze health reform proposals in the terms of the cost per newly insured individual.

Stephen Parente, a University of Minnesota economist who was serving as an American Enterprise Institute adjunct scholar, estimated in October 2009 that a private-market-oriented program based on use of exchanges and letting carriers sell coverage across state lines would ultimately reduce the uninsurance rate among U.S. citizens by 46 percent, to 18 million people, at an average cost of about $3,500 per newly insured individual. He estimated a proposal developed by Sen. Max Baucus, D-Mont., would cost about $4,100 per newly insured individual.

Consultants at PricewaterhouseCoopers estimated in January 2009, before Barack Obama took over as president, that the package of health system changes he was proposing would cost about $2,500 per newly insured individual.