As more older physicians postpone retirement, some people are calling for mandatory screening to make sure doctors are mentally and physically fit to practice.

Older doctors bring years of clinical experience to the job. But there are also downsides to aging, even for physicians.

One of these is highlighted by a new study, which found that Medicare hospital patients had a higher risk of dying when older physicians oversaw their care.

In the study, researchers analyzed data from over 736,000 Medicare patients aged 65 and over who had been admitted to the hospital between 2011 and 2014.

Their care was managed by 18,854 hospital physicians, with an average age of 41 years.

The mortality rate was higher for patients whose care was overseen by older physicians — increasing from 10.8 percent for doctors under 40 years of age to 12.1 percent for doctors aged 60 or over.

However, when they looked at only doctors with a high volume of patients, there was no increase in mortality for patients treated by older doctors.

In an interview with CBS News, study author Dr. Yusuke Tsugawa suggested that age may not be the main reason for the overall higher mortality rates among older doctors’ patients.

“It is more likely that what we are observing is the differences in training they have received,” he said.

Newer doctors are trained on the latest clinical evidence, skills, and technologies, so they may be more up-to-date.

Dr. William Norcross, director of the UC San Diego Physician Assessment and Clinical Education (PACE) Program, told Healthline that he sees physicians coming to his program who are “woefully out of date and have not kept up with the literature or the latest procedures.”

But these doctors are not always older.

“This may have nothing to do with aging. We see that sometimes in much younger doctors,” said Norcross. “It can just be a lack of professional drive to keep up with advancing knowledge.”

The study by Tsugawa and colleagues was published May 16 in The BMJ.

Researchers took into account patient, physician, and hospital characteristics that could have affected the results.

They also looked at only Medicare hospital patients, so these “observational” results may not apply to other types of patients, or to those cared for by other types of physicians.

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Earlier research also suggests that quality of care provided by doctors may decrease with age.

A 2005 review in the Annals of Internal Medicine found that older physicians may perform worse in terms of clinical knowledge, diagnosis, and providing screenings or preventive care. However, the results of the studies looked at were mixed.

There was also a lot of variation in doctors’ abilities.

A 2002 review in the journal Academic Medicine found that doctors’ mental and clinical abilities varied across all age groups, with differences among doctors increasing with age.

“Although the average performance tends to be lower, many older individuals perform at levels equal to — or above — those of their younger colleagues,” the authors wrote.

This shows up in the clinic, as well.

“One colleague is in his late 60s and he runs circles around many of our younger partners. The way he speaks and carries himself shows he still loves every minute of helping patients to feel better,” Dr. Thomas Rairdon, an anesthesiologist in private practice in San Antonio, told Healthline.

This variation in doctors’ ages makes it difficult to enforce a mandatory retirement for doctors.

“There’s never going to be a crisp, clear rule that doctors should give up practice at 70 or something like that,” said Norcross. “It’s just too heterogeneous to be able to say.”

Many physicians can continue to practice effectively for a long time.

“Most doctors up until 70 or 80 still have good cognitive reserve,” said Norcross. “But even with the ones that are beginning to decline, sometimes accommodations and modifications in their work is all that they need.”

Even physical conditions — like arthritis, stroke, or frailty — may not always mean the end of a physician’s career.

For example, a surgeon may need to avoid certain procedures, while still being capable of performing other ones. Or mild memory loss may not affect a physician’s clinical thinking. And failing eyesight may not matter that much for psychiatrists and family medicine doctors.

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As the number of older doctors in the United States increases, these issues will become more noticeable.

A 2015 study published in the Journal of Medical Regulation found that 30.9 percent of physicians with active licenses were over 65 years old in 2014, up from 26.3 percent in 2012.

An older doctor’s colleagues may be the first to notice age related changes that require attention.

“If a doctor is showing signs of poor judgment or age related fatigue, other doctors step in and help that aging doctor through the process,” said Rairdon.

A 2007 survey, though, found that 45 percent of doctors failed to report impaired or incompetent colleagues.

Dan Jennings, regional vice president of recruiting at The Medicus Firm, a national physician recruiting firm, thinks existing requirements for doctors — like licensure, board certification, and continuing medical education — may be enough to ensure that doctors are still practicing well.

“Physicians are already regulated to a significant extent, as to their clinical skills and acumen,” Jennings told Healthline. “There are several checks and balances and requirements for medical licensure and certification, to ensure that physicians are capable of medical practice.”

But many hospitals and medical groups are going one step further.

“About half of hospitals and medical groups in the United States either have or are developing some policies for the aging physician,” said Norcross. “So in the last 10 years, a lot of people are beginning to look at this and to do something about it.”

There are also calls for regular screening of older doctors.

“What I’ve endorsed, and the people in the PACE program have endorsed, is that at some point doctors participate — I would hope voluntarily — in some modest program of screening for health deficits,” said Norcross.

He added that this might include an independent history and physical exam, a cognitive function screening test, and eye and hearing exams.

The big question is when to start.

“What we don’t know is the optimal age that we should begin screening physicians,” said Norcross, “But I would say at least by 70, based on the available data.”

Rairdon has concerns that this type of screening may “create more bureaucratic red tape to make it even more difficult than it already is for doctors to treat patients the way they should.”

The goal of screening programs, though, is not to push doctors out of the profession or to make their lives difficult, but to identify problems early and provide doctors with support so they can continue to practice.

This can keep us from losing years of experience accumulated by older doctors.

“Some things — like wisdom, compassion, and things of that nature — may, in fact, improve with age,” said Norcross. “We don’t want to lose those qualities in the medical profession.”