Physicians take pharma-sponsored clinical trials with a grain of salt and are shrewd judges of a study’s methodological rigor.

That’s the upshot of a randomized study that looked at how 269 board-certified internists evaluated abstracts describing clinical trials of three hypothetical drugs – for hyperlipidemia, diabetes and angina. The abstracts were varied by methodological rigor (high, medium or low) and each included a note disclosing a funding source – from drug companies, the NIH or none at all. Follow-up questions assessed perceptions of rigor, confidence in results and willingness to prescribe the drugs.

The study found that physicians weighted their assessment of the rigor of a trial based on pharma funding, and that they were half as willing to prescribe those disclosing industry sponsorship as they were those disclosing NIH funding, regardless of methodological rigor.

“We found clear associations between the funding disclosure variations and physicians’ perceptions of a trial’s rigor and results,” the study authors wrote. “Regardless of the actual study design, physicians were less likely to view a trial as having a high level of rigor if funding by a pharmaceutical company was disclosed than if no disclosure statement was included … Similarly, in comparisons with trials for which no funding was listed and regardless of the study design, physicians were less likely to have confidence in the results of trials funded by industry … and were less willing to prescribe drugs described in such trials … These effects were even greater when industry-funded trials were compared with trials described as having NIH support.”

Especially unlikely to prescribe drugs studied in pharma-funded trials were older physicians, those trained in the US and – less surprisingly, perhaps — those who strongly agreed that industry funding can bias trial results.

“These findings have important implications,” the study’s authors wrote. “Despite the occasional scientific and ethical lapses in trials funded by pharmaceutical companies, it is also true that the pharmaceutical industry has supported many major drug trials that have been of particular clinical importance. Excessive skepticism concerning trials supported by industry could hinder the appropriate translation of results into practice.”

“For example,” they said, pointing to a New England Journal of Medicine poll of readers on the results of AstraZeneca’s JUPITER trial, “after publishing the results of a large, well-designed trial describing a new use for a widely-prescribed class of drugs, a leading biomedical journal noted that many of its readers believed that the results of the trial did not justify a change in clinical management, citing industry funding as a key reason for this conclusion.”