Schwartz, an emeritus professor of medicine at USC, died March 15 at his home in Los Angeles of Alzheimer's disease, said his wife, Tressa Ruslander Miller.
The founder of the Division of Nephrology at what is now Tufts Medical Center in Boston in 1950, Schwartz served as its chief until 1971. He then became the medical center's Chairman of Medicine and physician-in-chief.
From 1976 to 1992, the year he joined the faculty at USC, Schwartz was the Vannevar Bush University Professor and Professor of Medicine at Tufts University.
During Schwartz's early decades at Tufts Medical Center, he was one of a small number of people who developed the field of nephrology -- the specialty devoted to kidney diseases. -- and led landmark studies in the investigation of disorders in blood chemistry.
"He really was one of the founding fathers of nephrology," Dr. Deeb Salem, the current physician-in-chief and chairman of the department of medicine at Tufts Medical Center, said Friday. "The man was one of the smartest people I ever worked with and knew."
"He had an exceptional breadth of interests," said Dr. Jerome P. Kassirer, a distinguished professor at Tufts University School of Medicine and former editor in chief of the New England Journal of Medicine.
In the early '70s, Kassirer said, Schwartz "became interested in how doctors should make decisions, and he began working in the field called decision analysis.
"He, with other people as well, published an important paper showing that artificial intelligence computer programs could be used for diagnosis and management of kidney disease. But it was never implemented as a practical strategy."
Schwartz left his administrative post at Tufts Medical Center in 1976 after being awarded an endowed professorship at Tufts University. He then launched his second career studying various aspects of the American healthcare system.
"That included things such as hospital costs, the geographic distribution of specialists, malpractice insurance and the possible need for the rationing of healthcare," Kassirer said.
Schwartz's 1984 book "The Painful Prescription: Rationing Hospital Care," co-written with economist Henry J. Aaron, ignited a national debate on medical expenses.
"It was a very controversial book," Kassirer said, "but he stuck to his guns and never gave up the notion that some kind of rationing would be necessary."
In a 1998 interview with The Times, Schwartz said a "flood of medical advances, such as organ transplants, coronary bypass grafts, MRIs and new antidepressant and antipsychotic drugs, have added major expenses each year."
Americans, he said, "have a hard choice between two options, and that hard choice has not been openly faced by the government, by employers or by the general public.
"If we want all of these open-ended advances in medical care to be made available to virtually everyone who might benefit from them, costs will inevitably continue their upward surge, and we will devote an ever larger portion of our national resources to healthcare."
The other option, he said, "is to contain costs through rationing -- that is, by deciding which patients are to receive a particular treatment and which patients are to be denied it. That is a very painful idea and one totally unfamiliar to Americans who have health insurance, although, sadly, not to those who are uninsured.
"We can't have it both ways -- access to all useful care and containment of costs."
Schwartz was born May 16, 1922, in Montgomery, Ala. He served in the Army during World War II and received his undergraduate and medical degrees from Duke University.
As he looked back on Schwartz's long career, which included more than a decade as a principal advisor to the Health Science Program at the Rand Corp., Kassirer described him as "a brilliant visionary."
"He was not only creative but curious, with amazing energy and persistence in achieving his goals," Kassirer said. "I think quite frankly that it's a cruel and ironic twist that a man who is so cognitively keen, so curious, so creative and so devoted to intellectual sparring should become a victim of Alzheimer's forgetfulness."
In addition to his wife of 19 years, Schwartz is survived by his children from a previous marriage, Dr. Eric Schwartz and Laurie Schwartz Naparstek; his stepson, Joshua D. Miller; and five grandchildren. His son Kenneth B. Schwartz died in 1995.