A leading U.S. senator is calling on federal regulators to share the results of an investigation into the dialysis industry, where critics say a "duopoly" has compromised the quality of critical, lifesaving kidney care.

Two companies now own nearly 75% of all U.S. dialysis clinics — nearly 5,600 in total, a CBS News investigation reported earlier this year. Sen. Richard Blumenthal, a Connecticut Democrat, said in an interview with CBS News he is troubled by the "hallmarks of unlawful abuse of market power."

"The government may feel it has no leverage against two companies that provide for almost all the dialysis treatment in the country," Blumenthal said in an interview with CBS News. "But it has failed to use more leverage, including its antitrust powers against those companies."

The F

See Full Page