The lawsuit was filed in 2002 and is based on a whistleblower's claim that DaVita overused Epogen, an anemia drug made by Amgen, over a 10-year period.
DaVita says its physicians did nothing wrong and stand by their anemia management practices, but the company says the agreement is in the best interest of its shareholders. In addition to $55 million, the company will pay attorney fees.
Epogen boosts oxygen-carrying red blood cells, reducing the need for painful blood transfusions. However a study in 2009 suggested Epogen and other drugs like it can double the risk of a stroke.
Denver-based DaVita runs about 1,800 outpatient dialysis centers nationwide.