Studies concluding U.S. reviews of medical devices lag behind those in Europe and drive up costs for makers are flawed, according to editors of three medical journals, Bloomberg News reported.

Those studies were unfit for a peer-reviewed journal, editors of the New England Journal of Medicine, the Journal of the American Medical Association and the Archives of Internal Medicine wrote in letters to Democrats on the House Energy and Commerce Oversight and Investigations Subcommittee.

California Rep. Henry Waxman, the top Democrat on the panel, asked the editors to review the studies in advance of a subcommittee hearing on device approvals, said Karen Lightfoot, a Waxman spokeswoman.

A Stanford University study released in November that surveyed 204 medical-device companies found that high-risk devices took an average of 54 months to gain FDA approval, compared with 11 months in Europe. A California Healthcare Institute analysis from February concluded inefficiency at the FDA was pushing jobs and business abroad.

Representative Joe Barton of Texas, a senior Republican on the Energy and Commerce panel, has urged the FDA to cut the red tape and makes its review process for devices more consistent.

The Stanford study led by Associate Professor of Medicine Joshua Makower concluded the average U.S. development cost to get devices cleared ran from $31 million for a lower-risk product to $94 million for one with higher risks, and is featured on the web site of the Advanced Medical Technology Association, a Washington lobbying group representing device makers.

The company data at the heart of the study isn’t typical fare for clinical journals, said Makower, in a telephone interview. “They have not brought their own data,” he said of his detractors. “They have a lot of opinions but no data.”

Makower received responses from only 20% of the 1,000 device-makers polled for the study, said Jeanne Ireland, the FDA’s Assistant Commissioner for Legislation, in a July 18 letter to Waxman. Some companies that responded had never had a product evaluated by the agency, she said.

“These reporting rates are likely to produce an inherently biased result because they are not based on a representative sample of all medical-device companies,” Ireland wrote.

Makower said a 20% response rate is “a reasonable and substantial” cross-section with which to make a judgment.

Other editors providing comments to the House panel were Howard Bauchner, editor-in-chief of the Journal of the American Medical Association, and Rita Redberg, editor-in-chief of the Archives of Internal Medicine.