What Is a D.O.?

A few years ago, while searching for a new primary care doctor, a woman at the front desk of a local practice sent me the name of a well-regarded physician — with a caveat.

He’s a D.O., she almost whispered, which she assured me was “basically the same” as an M.D. Was it? If so, why had she felt the need to bring it up? Even after several appointments, I felt no closer to understanding what my doctor’s credential meant or whether it mattered to my care.

So, for the past few weeks, I’ve been digging into this question: What is a doctor of osteopathic medicine? This is, I’ve discovered, a timely question. The number of D.O.s is growing quickly: More than a quarter of all medical students in the U.S. today are attending osteopathic schools. Today, there are more than 150,000 practitioners, quadruple the number three decades ago.

In today’s newsletter, I’ll explain who they are — and what the changing face of medicine might mean for you.

Why is the group surging?

It’s about supply and demand.

The U.S. population is growing. Lots of people want to be doctors, and many more need medical care. But the number of spots at traditional medical schools has grown very slowly. The number at osteopathic schools, however, has ballooned in recent years. Fourteen campuses have opened in the last five years alone, creating thousands of training slots.

The profession has gained traction in places, often rural, where M.D.s are in short supply. Osteopathic schools are often in “medically underserved” areas like Kirksville, Mo.; Harrogate, Tenn.; and Detroit. Nearly 60 percent of D.O.s are primary care doctors — which pays less and is less popular among M.D.s.