Over the course of just five months in 2013, US doctors received more than US$3.5 billion in consulting fees, travel reimbursements and gifts from pharmaceutical and medical-device companies.

That revelation comes from Open Payments, a database launched on 30 September by the US Centers for Medicare and Medicaid Services (CMS). Transparency advocates praise the move, but others say that such disclosures can have unintended effects on the relationships between patients, physicians and the companies that pay them.

The CMS database was created by the Affordable Care Act, the health-care law better known as ‘Obamacare’, which requires biotechnology companies to disclose any payments greater than $10 made to any of the 546,000 physicians affected by the law.

Such disclosures appeal to patients, who want to know whether their doctors are compromised by industry ties, says Sunita Sah, an ethicist at Georgetown University in Washington DC. Sah has found that when given a choice, providers of medical or legal advice are more likely to disclose their conflicts — especially if they do not have any1.

But physicians and the biotechnology industry worry that the database will backfire. Thus far, the CMS site has proven difficult to use — lacking such tools as a search bar — and the agency says that one-third of its data has problems. “Publishing inaccurate data leads to misinterpretations, harms reputations and undermines the trust that patients have in their physicians,” the American Medical Association warned in a 30 September statement.

Even without those problems, trade groups such as the Pharmaceutical Research and Manufacturers of America and the Biotechnology Industry Organization warn that patients have too little information about what conflict of interest actually means. “It’s very difficult to distinguish real consulting and research money from gifts — putting it nicely — that are really bribes,” says George Loewenstein, an economist at Carnegie Mellon University in Pittsburgh, Pennsylvania. “It’s very likely to just introduce a lot of noise into individual patients’ decision making.”

Susannah Rose, an ethicist at the Cleveland Clinic in Ohio, says that the effects of supplying such information are not always straightforward. Some studies suggest that patients are likely to trust a physician who has the support of industry. “If they are so good that they’re actually getting paid a lot of money, it must be a good indication of their quality,” Rose says, adding that the disclosure also makes the physician seem more honest2.

But more research suggests that patients trust a physician less when they know that he or she has a potential conflict of interest, which is why context (such as the nature of the relationship with industry) is particularly important, Sah says. Patients are actually more likely to follow the advice of a doctor they think is biased owing to a relationship with industry. Patients “don’t want to signal distrust”, Sah says. “Even if they distrust the advice, they don’t want to insult the doctor.” But, she adds, they are less likely to return to that physician3.

Some research suggests that researchers themselves are more likely to discount academic papers that are funded by industry, regardless of how well the studies are designed. In addition, researchers are more likely to trust a paper stating that there is no conflict of interest than one that does not4.

Loewenstein is eager to see whether US doctors and industry change their behaviour in response to the disclosures. Some research suggests that experts who disclose conflicts of interest are more likely to feel “morally licensed” to give biased advice5. And Loewenstein says that there can be a “tell-tale heart effect”, in which doctors reject gifts to avoid having to later disclose them. Companies may also stop offering such compensation.

Sah says that refusing money from industry could hurt research efforts, she says, which is what the industry organizations fear. Or pharmaceutical companies may start finding new, creative ways to route the money to physicians — gifting it to hospitals or educational programmes, for example.

The extent to which industry money influences a physician’s decision making is hard to measure, says Loewenstein. Data on gifts received and prescriptions written over time are scarce and difficult to analyse. “It’s inconceivable that pharma would be so naive as to make so many gifts if they had no effect on the bottom line,” he says. He and other researchers hope that the new database will help to make a more quantitative assessment, but he says that it will probably be many years before they can find good answers.