Protesters against the US Senate Republicans' healthcare bill hold a rally outside the US Capitol in Washington, DC, June 28, 2017.

Money doesn't always buy healthiness.

The U.S. spends more on health care than 10 other countries in a study by The Commonwealth Fund, but was found to have the worst health-care system.

Health-care spending accounts for 16.6 percent of the U.S. gross domestic product, 5 percentage points more than Switzerland, the next closest country. Yet in a measure of health-care system performance among 11 high-income nations, the U.S. ranked dead last.

The United Kingdom's health-care system was ranked the best, followed by Australia and the Netherlands. France placed second to last, and Canada placed third to last.

Of the countries studied, the U.S. is the only one that does not offer universal health insurance coverage. Each of the other 10 countries, though, uses a slightly different model.

The study's publication comes one day after the Senate Republicans released details of a new bill to repeal and replace the Affordable Care Act.

"We have not had time to digest the (Senate) bill, but in general, the proposals we've seen would actually reverse progress, especially on insurance coverage," said Eric Schneider, senior vice president of policy and research at The Commonwealth Fund.

The study identified four main problems plaguing the U.S. health-care system: a large number of uninsured patients, limited primary care, administrative burdens, and disparities in care between higher- and lower-income patients.

The House and Senate proposals do not address problems the Affordable Care Act, also known as Obamacare, does, specifically the availability of primary care, nor do they simplify the insurance system, said David Blumenthal, president of The Commonwealth Fund. The disparity of access would "likely not get better" because the proposals include cuts to Medicaid.

One part of the health-care debate has been whether to create high-risk insurance pools. The Netherlands, the second-highest ranked country in the study, does the opposite and makes sure the risk is balanced, Schneider said.

Countries that rely on minimal or no cost sharing health systems scored better than the U.S., said Blumenthal. Evidence suggests that cost sharing does not improve a country's health-care performance, he said.