Today, we are publishing the first findings from our investigation of dialysis, a treatment relied upon by hundreds of thousands of people suffering from kidney failure. The United States spends billions of dollars annually on dialysis, nearly $80,000 per patient. But by many measures, Americans fare worse than citizens receiving the treatment in other industrialized countries. Critics have long said these outcomes could be substantially improved if lawmakers found the will to re-invent a flawed system of incentives and oversight. For decades, little progress has been made.

As we reported these stories, we made a discovery relevant to every patient on dialysis. We learned that the federal Centers for Medicare and Medicaid Services gathers extensive data about the quality of care at the nation's dialysis facilities and has it analyzed at taxpayer expense. Until now, the government has kept most of that information secret, available only to dialysis providers and bureaucrats.

Patients visiting the CMS website, Dialysis Facility Compare, have had to settle for a watered-down version of the data. They have no access to the government's underlying numbers that track whether death, hospitalization and infection rates are above or below what is expected.

In essence, federal officials have kept two sets of books, one for patients, the other available only to a handful of industry officials and government overseers. The lack of detailed information about the quality of competing dialysis facilities removed the force of the free market by denying patients the power of informed choice.

For two years, ProPublica reporter Robin Fields prodded CMS officials to release this data under the Freedom of Information Act. Initially, she was told by the agency that the data was not in its "possession, custody and control." After state officials denied similar requests for the data, saying it belonged to CMS, the agency agreed to reconsider. For more than a year after that, officials neither provided the data nor indicated whether they would.

Asked why the data hadn't been released to the public, officials told Fields that some of it was disputed or crude -- and that patients could easily misinterpret what it meant.

A few days ago, after the story we are publishing in December's issue of The Atlantic magazine went to press, CMS agreed to release several years' worth of the data. We plan to make it available on our website as soon as possible in a form that will allow patients to compare local dialysis centers.

ProPublica's reporting on dialysis, which will continue in the coming weeks, may be useful as the new Congress takes up anew the question of how to control the cost and quality of health care.

Our reporting found many reasons for the flaws in the dialysis system. Patients are disproportionately drawn from the ranks of the disadvantaged and have not effectively lobbied for improvements. The American approach to kidney disease, with uninsured patients receiving haphazard care until they qualify for dialysis, means U.S. patients are often sicker when their disease is treated.

Some of these issues will undoubtedly prove difficult to address. But the release of the government's previously undisclosed data marks a new chapter. For the first time, dialysis centers will face the full force of transparency. At ProPublica, we seek to publish stories that have impact. This one has had an effect even before it appeared.