By Rebecca Adams, CQ Roll Call

April 30, 2015 -- All of the 10 most commonly prescribed drugs in 2013 were generic drugs, according to a Centers for Medicare and Medicaid Services (CMS) analysis of data that federal officials recently released for public analysis.

The heartburn relief drug Nexium and the drug Advair Diskus, used to control asthma and chronic obstructive pulmonary disease, captured the most drug revenues that year. Neurologists prescribed drugs that resulted in far higher costs per claim than internists, family practice doctors or psychiatrists.

The findings are representative of what can be harvested from a massive database of Medicare prescription drug claims—with 23 million lines of information about 1 million different medical providers—that CMS officials opened up to the public last week. 

CMS has already released other data sets with information about physicians' claims, hospital charges, and payments from drug companies to doctors or researchers.

"It's important for consumers, their providers, researchers, and other stakeholders to know how many prescription drugs are prescribed and how much they cost the health care system, so that they can better understand how the Medicare Part D program delivers care," said CMS Acting Administrator Andy Slavitt in announcing the availability of the new data. 

The information could answer more questions about how often doctors prescribe certain drugs and how much they cost, how drug use varies across the country and how often physicians prescribe brand-name drugs instead of generics. 

The providers are identified but patients are not in the data set. The new data show the patterns of doctors or other health care providers who altogether prescribed about $103 billion in prescription drugs and supplies through the Medicare prescription drug program. 

The data shows the prescribing patterns of health providers for more than 3,000 drugs. Federal officials plan to release new numbers every year. 

CMS Deputy Administrator Sean Cavanaugh said that federal officials rely on the data as they wrestle with policy questions about Medicare prescription drug spending, but said that the data are large and diverse enough that outside analysts "may develop insights we may have missed." He also said that the public disclosure of drug spending could "help energize the private sector" to find efficiencies and improve federal programs. 

Niall Brennan, Director of the CMS Office of Enterprise Data and Analytics and Chief Data Officer, called the release another step in making big data available to the public. 

The information that the public can now see includes the total number of prescriptions that a doctor prescribed for each type of drug. That includes original prescriptions and any refills, and the total drug cost paid by beneficiaries, health plans, and other payers.

The data set is based on information about drug spending for 35.7 million beneficiaries enrolled in the Medicare Part D prescription drug program, who make up about 68 percent of the people in Medicare. About 23 million of the beneficiaries are in stand-alone prescription drug plans and 13 million are in Medicare Advantage private health insurance plans that cover prescription drugs.

"We believe sharing this data is the right thing to do," said Cavanaugh.