Dr. Allan Collins ... is president of the National Kidney Foundation. In 2004 ... the pharmaceutical company Amgen, which makes the most expensive drugs used in the treatment of kidney disease, underwrote more than $1.9 million worth of research and education programs led by Dr. Collins. In 2005, Amgen paid Dr. Collins at least $25,800, mostly in consulting and speaking fees. The payments to Dr. Collins and the research center ... come from Minnesota, the first of a handful of states to pass a law requiring drug makers to disclose payments to doctors. The Minnesota records are a window on the widespread financial ties between pharmaceutical companies and the doctors who prescribe and recommend their products. From [1997] through 2005, drug makers paid more than 5,500 doctors, nurses and other health care workers in the state at least $57 million. More than 100 people received more than $100,000. Research shows that doctors who have close relationships with drug makers tend to prescribe more, newer and pricier drugs - whether or not they are in the best interests of patients. Drug companies want somebody who can manipulate in a very subtle way," said Dr. Frederick R. Taylor. Kathleen Slattery-Moschkau, a former sales representative [said] "it all comes down to ways to manipulate the doctors." Some of the doctors receiving the most money sit on committees that prepare guidelines instructing doctors nationwide about when to use medicines. "It is critical that the experts who write clinical guidelines be prohibited from having any conflicts of interest," said Dr. Marcia Angell, a former editor of The New England Journal of Medicine.