I know this will come as a shock. But there are conflicts of interests at every level of the medical establishment.
In our market driven culture we think transparency is essential, that is price and product information must be available to consumers in order to determine utility and value. But what if the system is set up to obfuscate and subtly deceive? In health care price is obscured; patients are often in crisis and unable objectively evaluate information; and information available about the medical product, procedure and outcome is biased. This article in the NY Times points out some of the problems with industry sponsored research.