Even as the Patient Protection and Affordable Care Act pushes to get health insurance for millions more Americans, the law is meant to work just as hard at bringing down the cost of Medicare. On this front, a principal goal has been to move the system away from fee-for-service payments, removing the incentive to provide unnecessary care. Then, the reasoning goes, there will be less wasted effort, so the quality of health care will rise even as the cost falls.

That’s a worthy goal. So it was discouraging to learn last month that a nationwide test of accountable care organizations - - a promising new payment system in which doctors and hospitals coordinate their efforts and share in the savings that may result -- didn’t do so well in its first year. The pilot project led to Medicare savings of just 0.4 percent. Of the 32 hospital and health-care systems involved, only 13 saved enough to get money back, and nine have since pulled out of the project.

That’s not terribly alarming on its own. After all, any effort to reform our behemoth medical system is bound to take time and suffer setbacks. But now comes further reason to worry: The U.S. Centers for Medicare and Medicaid Services has missed the reporting deadlines, some of them mandated by Congress, for at least nine other payment-reform experiments -- and, in many cases, won’t even say how late the agency is. Nor will CMS say when the data will be revealed.

The projects for which reports are past due include:

-- The Medicare Care Management Performance demonstration, which paid doctors extra for using health data to better treat their patients. CMS was supposed to issue its final report to Congress two years ago. Today, it won’t let us know even when the report will be released.

-- The Medicare Physician Group Practice demonstration, an earlier attempt at ACO efforts. The program ended in March 2010, and no report is in sight.

-- The Medicare Acute Care Episode demonstration, which is testing the use of bundled payments for what’s called a single episode of care -- in this case, certain types of orthopedic or cardiac surgeries. The project started in May 2009; again, CMS won’t say when we’ll see the report.

-- The Medicare Hospital Gainsharing demonstration, which examined how to get health-care providers to work together. This project ended in the summer of 2011; a full evaluation was supposed to go to Congress in March.

-- The Nursing Home Value-Based Purchasing demonstration, another ACO project, which began in July 2009. CMS won’t say when the report will be out.

-- The Medicare Coordinated Care demonstration, which started in 2002 and tested various ways to improve health outcomes for patients with complicated chronic conditions. CMS’s website says the project is no longer active, but the agency told us it’s been extended at one site. The result: Final data for the other 14 sites remain unavailable.

Reports for all these projects are under review and when that’s done, they will be released, according to the agency, though it would give no timeline.

CMS isn’t just sitting on the results. In some cases, it has barred the hospitals and health-care systems that took part in the projects from discussing what effect these experiments have had on costs. It has also instructed some health groups not to discuss future projects.

The blackouts only increase our curiosity -- and worry -- about how well those experiments are working.

There’s little doubt that such information is valuable. CMS requires the hospitals and health systems it works with to notify it right away of any “unanticipated results.” Presumably, other insurers would be equally interested in knowing about those unexpected results now, rather than waiting for years. Private health insurers are experimenting with many of the same payment reforms that CMS is testing, and they would benefit from any of the lessons provided by those projects, whether they are succeeding or failing.

By keeping a lid on this information, CMS keeps the public in the dark about the fate of its efforts, which will in turn shape the future of Medicare. And it undermines Obamacare’s goal of helping the entire health-care system save money.

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