Doctors need to fully analyse their relationships with pharmaceutical companies and remember that there is no such thing as a free lunch, according to a leading US professor.

Eric Campbell, an associate professor at Massachusetts General Hospital and Harvard Medical School, has written a piece in the New England Journal of Medicine in the wake of the recently-introduced Physician Payments Sunshine Act, which requires firms with annual revenues of more than $100 million to disclose the amount of money they give to physicians — whether in the form of a free dinner, holiday or a consulting fee.

Prof Campbell writes that five US states (Minnesota, Vermont, Maine, West Virginia, and California) plus the District of Columbia have now enacted similar disclosure laws and “the movement toward increased transparency is gaining steam”, noting that “the nature, extent, and consequences of physicians' relationships with industry have become one of the most fiercely debated issues in health care today”.

He says that although most doctors deny that receiving free lunches, subsidised trips or other gifts from pharmaceutical companies has any effect on their practices, “research has shown that physician–industry relationships do influence prescribing behaviour”. If they did not, “companies wouldn't spend $19 billion each year establishing and maintaining them”.

However Prof Campbell also says that “many, if not all, of the drugs currently on the market simply wouldn't exist if it weren't for relationships whereby physicians enroll patients in manufacturers' clinical trials and provide companies with advice on drug development”. He adds that simple attendance at an industry-sponsored luncheon or dinner may lead physicians to recommend beneficial drugs that are being underprescribed but warns that “there is no reason why an educational activity needs to be accompanied by an expensive meal or a trip to a tropical resort”.

He concludes by welcoming the various systems being put in place for more stringent disclosure requirements but says that individual physicians can make a stand too. “They can start by recognising that such relationships are designed to influence prescribing behavior and by carefully considering the potential effects that their own associations may have on their patients,” he says, and bear in mind that “the costs of industry dinners, trips and other incentives are passed along to their patients in the form of higher drug prices”.