A patient plagued with difficult-to-control asthma is at the end of his rope, until his doctor suggests joining a clinical trial. After enrolling, he’s no longer just a patient but also a research subject, and he’ll be testing one treatment approach while others use a different one. Such studies are the bedrock of medical science: They ensure that medicines and procedures are safe and effective.

Before participating, he needs to be told what he’s getting himself into — the potential benefits and harms — in a process known as informed consent.

The federal government has regulated informed consent for decades. But some institutions and advocacy organizations, including the Association of American Medical Colleges, are warning that proposed federal guidelines could have a chilling effect on innovation while fundamentally altering which studies get done.

The six-page guidance— which could be finalized this year — calls for greater transparency in studies that compare how effective different treatments are. These studies, known as comparative effectiveness research, are among the tools being tapped by the Affordable Care Act to help curb health-care spending.

The proposed policy says researchers must clearly explain all risks that people might face by participating, and it redefines those risks to include any harm that is being measured or tracked by the study, even if patients would face those effects when receiving regular treatment from a health-care provider. Current rules on informed consent don’t explicitly call for such clear and extensive explanation of potential dangers in studies.

The Department of Health and Human Services, which is accepting feedback on the proposal until the end of January, began the process of updating the policy after a controversial 2009 experiment that studied extremely premature babies.

That study aimed to determine the appropriate level of supplementary oxygen for infants born at 24 to 27 weeks gestation, a group that is prone to death and eye disease. The randomized test compared lower and higher doses of oxygen commonly used at the time, with the goal of reducing instances of retinal disease without hurting the babies in other ways.

But HHS found that researchers hadn’t properly warned the babies’ families about the risks. In the low-oxygen group, 130 of 654 infants died, vs. 107 of 662 infants in the high-oxygen group. Babies in the low-oxygen group who survived had more eye problems than those in the high-oxygen group.

Unless the proposed informed-consent guidance undergoes major revision, the change would create uncertainty for institutional review boards — the independent committees that approve research projects at medical institutions — and for researchers, said Ann Bonham, chief scientific officer of the Association of American Medical Colleges.

Both parties, she said, would have to choose how to interpret the guidance, perhaps taking a conservative approach and issuing long lists of possible risks without proper context. She believes this might have a chilling effect on the interest of researchers in conducting studies and in their ability to sign up patients.

At a recent Institute of Medicine meeting, Greg Simon, a Seattle-based psychiatrist who conducts clinical trials with the Group Health Research Institute, says the proposed rules could lead to standards that make sense for some studies — where a certain treatment clearly presents a strong risk — while overstating danger in others.

But in a public presentation, Jerry Menikoff, director of the federal Office of Human Research Protections in the Department of Health and Human Services, said the new language wouldn’t require overwhelming or confusing lists, but rather clear and thorough explanations of the dangers that studies present — explanations that he suggested are currently lacking.

“We don’t think it should be confusing to write a good, brief consent form that accurately lays out the potential risks and benefits of the study,” Menikoff said in an e-mailed statement to Kaiser Health News.

No matter what kind of study, people deserve to know the relative risks of getting one treatment vs. another, said Michael Carome, director of the health research group at Public Citizen, a public interest group that has long called for stronger regulations. Though the proposal may be confusing, it doesn’t need more than cosmetic editing, he said. “The guidance, in terms of its overall intent and basic conclusion, is more or less on target.”

“The concern that people will no longer enroll in research if we describe the risk, I think, doesn’t make sense,” he added.

And given the proliferation of videos, online forms and other kinds of technology, getting consent doesn’t need to be cumbersome, Menikoff said in the statement, meaning that large numbers of subjects can be warned of study risks “in an efficient and cost-effective way, thus respecting their ability to choose which risks they are willing to be exposed to.”

Arguments that the revised policy would require consent forms to include 20-page lists of all minor risks are misguided, said Lois Shepherd, a professor at the University of Virginia who specializes in bioethics.

“What [HHS is] trying to get at is the heart of what people need to know in order to volunteer for research,” she said. For clarity, she said, the guidance could be edited to include examples of consent forms — so that review boards and researchers know exactly what they must do.

But the goal should be promoting more-open conversations between research interests and patients rather than trying to achieve understanding through a consent form, said Sharon Terry, president of the Genetic Alliance, a nonprofit advocacy organization. “That doesn’t do justice either to the research or the participants,” she said.

This article was produced by Kaiser Health News. KHN, an editorially independent news service, is a program of the Kaiser Family Foundation, a nonpartisan health-care-policy organization.