Arnold S. Relman, who was an influential editor of the New England Journal of Medicine, in his Boston office in 1979. (DMT/AP)

Arnold S. Relman, a physician and writer who as the longtime editor of the New England Journal of Medicine helped shape debates about health care, how it is developed and how it is paid for, died June 17 — his 91st birthday — at his home in Cambridge, Mass.

The cause was melanoma, his son John Relman said.

First published in 1812, the New England Journal of Medicine is regarded as one of the most influential publications of its kind in the United States. It is read weekly by hundreds of thousands of doctors, researchers, policymakers and others seeking news of the latest developments in medical science.

With its imprimatur, new studies, drugs and the researchers who pursue them can vault to prominence, as their appearance in the Journal is often perceived as an authoritative endorsement of their value or at least their promise.

As editor from 1977 until his retirement in 1991, Dr. Relman played a leading role in guiding the Journal’s editorial priorities and philosophy. A kidney specialist, he had gone years without seeing a patient but may have been, according a Washington Post profile, “the most powerful doctor in America.”

Dr. Relman continued the Journal’s tradition of publishing major research findings, such as the discoveries of the drug AZT’s therapeutic benefits for HIV/AIDS patients and the value of aspirin in preventing fatal heart attacks.

He became particularly known for pushing important but often divisive discussions of social, economic and political questions — most prominently, the matter of money in medicine.

As early as 1980, he railed against the business interests he termed the “medical-industrial complex.” In the Journal and elsewhere, he warned against the danger of for-profit hospitals, nursing homes and other medical facilities.

“Doctors have to be advocates for their patients,” he told The Post in 1988. “They can’t be businessmen worrying about the bottom line.”

Dr. Relman’s critics argued that he was reflexively opposed to the for-profit business model, which, they argued, was needed to compete with nonprofit institutions that also were imperfect. His admirers regarded him as an early voice for reform in a broken industry.

“When I started out, patients trusted their doctors implicitly,” he told The Post. “The good faith was assumed. But the idea of the doctor as Samaritan has faded. Patients think of doctors as businessmen now, more concerned with their own income. That’s not good for the health of this country.”

Dr. Relman also attracted attention for his insistence on the Journal’s long-standing embargo policies. According to the Ingelfinger Rule — so named for a previous editor — the Journal declined to publish work that already had been publicized widely in scientific detail.

The policy included exceptions for public health emergencies and other causes. Critics maintained that the Journal was using its status to manipulate — to its competitive advantage — the release of information with broad public value.

Dr. Relman defended the Journal’s policy, arguing that it allowed the peer-review process time to run its course and that it prevented lay media organizations from misinterpreting partial elements of studies.

“Premature publicity about medical research and publicity about work that has not yet been documented cause confusion among laymen and the profession alike,” he wrote in an editorial published in the Journal in 1981.

“We believe strongly in the importance of an informed public and in the public’s right to know, but we also believe that it is important to take the time to make sure that the public is not misled.”

He regarded the Journal as a scientific gatekeeper and a tool for physicians at a time of dramatic advances in research.

“People expect much more of medicine than they ever did before,” he told The Post. “They almost expect doctors to keep them alive indefinitely. Expectations have surpassed the skills in many cases.”

Arnold Seymour Relman was born June 17, 1923, in Queens, N.Y. He studied philosophy and biology at Cornell University in Ithaca, N.Y., where he received a bachelor’s degree in 1943. Three years later, he received a medical degree from Columbia University’s College of Physicians and Surgeons.

In the early years of his career, he was a medical professor at Boston University, editor of the Journal of Clinical Investigation and chairman of the department of medicine at the University of Pennsylvania.

At the New England Journal in 1988, Dr. Relman passed day-to-day editing operations to a deputy, Marcia Angell, who later became the publication’s editor and whom he married in 2009.

His first marriage, to the former Harriet M. Vitkin, ended in divorce. Besides Dr. Angell, of Cambridge, survivors include three children from his first marriage, Dr. David A. Relman of Palo Alto, Calif., John P. Relman of Washington and Margaret R. Batten of West Newton, Mass.; two stepdaughters, Dr. Lara Goitein of Santa Fe, N.M., and Elizabeth Goitein of Washington; and 10 grandchildren.

After his retirement, Dr. Relman continued writing for the Journal and became a professor of medicine at Harvard University. His book “A Second Opinion: A Plan for Universal Coverage Serving Patients Over Profit” was published in 2007.

In 2002, he and Angell published in the New Republic magazine an account of the American pharmaceutical industry that was honored with a prestigious George Polk Award.

In February, writing in the New York Review of Books, he chronicled his hospitalization after a fall the previous year, 10 days after his 90th birthday, in which he broke his neck and nearly died. He attributed his recovery to the care he received, the support of his relatives, his own medical training and, perhaps, a will to live.

“I wanted to stay around as long as possible to see what was going to happen to my family, to the country, and to the health system I was studying so closely,” he wrote. “Perhaps I was too engaged in life to allow death to intrude right then.”