We told you so.

That’s essentially what two leading House Democrats said Wednesday in the wake of new findings showing that wealthier people are much more likely to open health savings accounts (HSAs).

Democratic Reps. Pete Stark (Calif.) and Henry Waxman (Calif.) seized on this finding as a vindication of Democratic arguments that the debut of HSAs in 2004 provided wealthy people a means to avoid taxes and exit broad insurance pools but did nothing to give the uninsured greater access to health coverage.

The report also found that HSA holders use only about half of the money they save on medical expenses and leave the remainder in their accounts. When an HSA holder turns 65, he or she is allowed to withdraw the entire balance of tax-free and spend the money for any purpose, not just medical expenses, without paying a penalty.

“The GAO confirms that HSAs are not the way to meet the healthcare needs of most Americans. Instead, they are an effective tax shelter for people whose average incomes are nearly triple that of average tax filers,” said Stark, who chairs the Health Subcommittee of the Ways and Means Committee.

“This report provides further evidence that we need to re-examine whether this is the right way to use the government’s resources to address our healthcare needs,” said Waxman, the chairman of the Oversight and Government Reform Committee. Stark and Waxman requested the GAO study.

The accounts and plans are becoming increasingly more common, particularly among workers who are offered HSAs in addition to — or in lieu of — HMOs and other types of health benefits.

HSAs are tax-free savings vehicles for money to be used to pay for medical expenses. Unlike other tax-advantaged medical expense accounts, HSA holders do not have to spend their entire contributions in a single year but can accrue money over their lifetimes. In 2008, most individuals are limited to contributing $2,900 a year and families to $5,800.

People or couples 55 years of age or older but not enrolled in Medicare can set aside an additional $900. Those limits are subject to annual cost-of-living increases.

The savings account must be paired with a high-deductible health insurance plan that requires individual enrollees to pay at least the first $1,100 out of pocket and families to pay $2,200. These insurance plans limit annual out-of-pocket spending to $5,500 for an individual and $11,000 for a family. The insurance can be purchased on the individual market or through an employer. Employers are increasingly more likely to offer an HSA with insurance and, in some cases, will add money to workers’ accounts.

HSAs are an ideological touch point in the healthcare reform debate. For conservatives, they represent an opportunity to inject market forces and consumerism into a healthcare system in which the vast majority of patients are unaware of the true costs of the care they receive. For liberals, HSAs are yet another means for the wealthy to shield their income from taxation and withdraw from participation in the health insurance market at large, which will drive up premiums for everyone else.

This divide is evident in this year’s presidential contest, as presumptive Republican nominee Sen. John McCain (Ariz.) includes expanding HSAs as a central component of his healthcare platform, while Democratic contenders Sens. Hillary Rodham Clinton (N.Y.) and Barack Obama (Ill.) reject the notion that the free market alone can solve the problems with the healthcare system.

“This has been the common smear from HSA opponents, particularly Chairman Stark and others in the House majority who have opposed any efforts to help acquaint consumers with the cost of healthcare,” responded Neil Trautwein, a VP and employee benefits counsel for the National Retail Federation .

Because of their relatively low annual contribution limits, HSAs are not the best way to avoid paying income tax, Trautwein added. “If I was … searching for tax shelters, I would find something better than that,” he said.

Trautwein suggested that the fact that people are contributing more to their accounts than they are spending is a good sign. “HSA holders are always encouraged to spend wisely and save up for future healthcare needs,” he said. “We ought to encourage more savings in society.”

Because these savings accounts have been available for less than four years, little data is available about the effects they have had on the insurance market, consumer behavior or healthcare costs.

The accounts and the high-deductible insurance plans that go with them are proliferating, however. As of January, 6.1 million people had them, up from 1.1 million in March 2005, according to information released Wednesday by the industry trade group, America’s Health Insurance Plans (AHIP).

“Employers and individuals across the country and across the age spectrum are choosing HSA plans, which are now an important part of the portfolio of coverage options offered by health plans,” AHIP President and CEO Karen Ignagni said in a statement.

During the same time period, the share of HSA holders in the individual market shrank from 64 percent to 25 percent.

Meanwhile, large employers have gravitated toward them, with 45 percent of the HSA market now composed of workers at large companies and their families, compared to 19 percent, according to AHIP.