WASHINGTON — With many seniors facing high medical bills, a congressional investigation has found that federal government websites meant to give Medicare patients basic consumer tools instead fail to provide adequate information on out-of-pocket costs and even quality of care.

The nonpartisan Government Accountability Office found that Medicare lacks clear procedures for getting useful information to consumers.

The report finds “critical weaknesses” in five consumer-information websites run by the Centers for Medicare and Medicaid Services that seek to inform how well hospitals, nursing homes, physicians and other Medicare providers are doing.

The GAO said a confusing layout, data gaps and lack of customized information make it virtually impossible for consumers to get the information they need and won’t be fixed anytime soon, even as the federal government plans new websites on the quality of hospice, inpatient rehabilitation and long-term care.

It is the latest report to detail problems in the government’s health care websites. The Obama administration has already grappled with the technology meltdown experienced last year by HealthCare.gov as well as glitches in the Sept. 30 rollout of data on payments doctors receive from drug companies.

“The GAO report reveals that there is a need to empower patients with better information on health care price and quality,” said Sen. Pat Toomey of Pennsylvania.

“Armed with the facts, it will be possible for consumers to obtain high quality care and drive down costs,” he said.

The GAO cautioned that due to a lack of clear policies or performance measures, CMS will likely continue to have “limited effectiveness in conveying relevant and understandable information on cost and quality to consumers.”

It cited a growing need for the information due to rising health care costs.

Jim Esquea, an assistant secretary at the Health and Human Services Department, wrote that CMS, an agency of HHS, was planning to expand its star ratings, already in use on its “Nursing Home Compare” website.

He also said HHS was committed to providing detail on estimated out-of-pocket costs “to the extent feasible” and had developed many internal procedures, although GAO said it had found no evidence that was the case.

The investigators cited a likelihood of continuing problems despite the government’s 2011 pledge under the Affordable Care Act to provide consumers complete and understandable information. While CMS has said it will make improvements, GAO pointed to limitations due in part to resistance from medical providers.