MDs and DOs: Does the difference in medical degree translate to a difference in patient care?

Dr. Yusuke Tsugawa discusses the outcome of a UCLA Health-led study comparing the two.
Body work
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5 min read

When people visit their doctors, they may not pay much attention to the two letters listed immediately behind their provider’s name – MD or DO.

The Dr. title is the same, but the designations of Doctor of Medicine (MD) or Doctor of Osteopathic Medicine (DO) depend on what type of medical school a physician attended.

MDs train in traditional – also known as allopathic – programs, while DOs attend osteopathic schools. Osteopathic schools have a stronger focus on holistic medicine. For instance, they typically include 200 hours of training in the musculoskeletal system and manipulation techniques such as stretching and resistance.

But do the differences matter for patients?

Researchers led by UCLA Health sought to compare quality of care between the two types of doctors who were treating hospitalized older adults. Senior author Yusuke Tsugawa, MD, MPH, PhD, associate professor of medicine at the David Geffen School of Medicine at UCLA, said the team found similar outcomes.

“The main takeaway of our research is that any distinctions between allopathic and osteopathic medical schools, in terms of training or student demographics, were not associated with differences in costs or quality of hospital care,” Dr. Tsugawa said.

MDs are far more prevalent than osteopathic doctors. But the topic is especially timely as the number of medical students training to become DOs has been on the rise, and as they serve vital roles in underserved areas.

“The findings of this study could contribute to the ongoing dialogue around the integral role of osteopathic physicians in American health care,” Dr. Tsugawa said. “Our findings should be reassuring for medical educators and patients.”

Patient outcomes

Researchers reviewed 2016-2019 hospital data for 329,500 people who were 65 or older. Among them, 77% were treated by MDs and 23% were treated by DOs. The DOs in the study were on average a few years younger than MDs and slightly more likely to be women.

Patient mortality rates were 9.4% among patients treated by MDs vs. 9.5% for those treated by DOs. Hospital readmission rates were 15.7% with MDs vs. 15.6% with DOs. Spending by Medicare to cover the doctor’s bills differed by only a dollar, at $1,004 vs. $1,003. Average length of stay was 4½ days for both groups of patients.

The findings were published in the June 2023 edition of Annals of Internal Medicine.

“Our hypothesis was that patient outcomes would be similar between MDs and DOs, given that medical education programs are quite standardized between allopathic and osteopathic medical schools,” Dr. Tsugawa said.

Similar training

Both traditional medical schools, including the David Geffen School of Medicine, and osteopathic medical schools require four years of study, followed by specialized training. Doctors from both kinds of schools spend three to seven years in residency, depending on their specialty.

Whether a future doctor attends a traditional medical school or osteopathic school, educational costs are comparable, with annual tuition typically starting in the $50,000s.

When it comes to academic performance, Dr. Tsugawa said test scores and licensing exam scores are similar between medical students regardless of the type of school.

MD and DO physicians are licensed by the same boards and held to the same requirements for practicing medicine.

Dr. Tsugawa said he doesn’t think patients will encounter any difference in their exam or experience, regardless of what type of doctor they see.

“In my opinion, patients do not notice the distinction between MDs and DOs,” Dr. Tsugawa said.

Rapid growth

Although DOs currently comprise about 10% of all physicians, their ranks are rapidly rising because of an increase in osteopathic medical schools. The study noted that the number of osteopathic medical students has nearly doubled in the past decade, with 1 in 4 U.S. medical students enrolled in an osteopathic school.

But despite the increase in osteopathic schools, Dr. Tsugawa said there was a lack of research comparing quality and costs of care between the two types of training.

“Given that an increasing number of patients are treated by osteopathic physicians, we thought that it was important to assess whether outcomes of patients treated by allopathic and osteopathic physicians differ,” Dr. Tsugawa said.

He said the reasons for the increase in osteopathic medical schools may be due in part to the extremely high bar set to create new allopathic medical schools. For instance, he said in one 25-year period, ending in 2005, nine osteopathic schools opened in the U.S. Only one traditional school opened during the same timeframe. Each type of school has a different accreditation body.

Dr. Tsugawa said that although he doesn’t know all the reasons for the differences in regulatory hurdles, the schools' different focuses may play a role.

“Osteopathic medicine traditionally has a stronger emphasis on primary care and less emphasis on research, which could potentially lower some of the barriers related to clinical affiliations and research infrastructure,” he said.

More differences between the two kinds of doctors emerge once they complete their education and training.

DOs are more likely to go into primary care medicine and work in rural and underserved areas, helping ease provider shortages in those arenas.

“It may be that the students who entered osteopathic schools have an original preference for primary care and rural practice,” said Dr. Tsugawa, who is also an associate professor of health policy and management at the UCLA Fielding School of Public Health.

He noted that a recent study found that osteopathic schools are more likely to have an admissions strategy for recruiting students who are likely to go into primary care and practice in rural areas.

Educational programs and influence of faculty and peers may also play a role, Dr. Tsugawa said. He said data from the American Association of Colleges of Osteopathic Medicine found that in 2017, 19% of students reported that they wanted to specialize in primary care, but by the time they graduated, that figure had risen to 34%.

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