An influential senator is demanding copies of contracts and conflict-of-interest policies from the National Quality Forum after allegations that kickbacks were paid to influence its patient safety guidelines. Sen. Charles Grassley cited "serious concerns" about how the Quality Forum vets its expert advisers and suggested the group may have endorsed a drug for a use the government hasn't approved. "This case calls into question NQF's due diligence and its obligation to prevent conflicts of interest or recommendations that violate officially approved uses," Grassley, R-Iowa, said in a letter to Dr. Christine Cassel, president of the nonprofit group, whose guidelines are widely adopted by health care providers.