SAN FRANCISCO — Hospitalist practice is evolving rapidly into its own specialty, distinct from its largely internal medicine roots.

That process of evolution is bringing up questions and challenges, some of which may have implications for not just the hospitalists themselves but for hospitals and other physicians as well, John R. Nelson, M.D., said at the annual meeting of the American College of Physicians.

Hospitalist practice already meets many of the criteria often used to define a distinct specialty, said Dr. Nelson, a past president of the Society of Hospital Medicine.

In addition to having their own society, hospitalists now have their own continuing medical education courses, a handful of residency tracks, and fellowship programs. Hospitalists are developing some distinct competencies, and plans for a hospitalist journal are in the works.

“We nearly meet all these requirements now, and the ones that we don't meet are coming soon,” Dr. Nelson said.

Current estimates suggest that 10,000–12,000 hospitalists are now practicing, up from a few hundred in the 1990s. And there continue to be more hospitalist positions opening than there are applicants to fill them.

A conservative estimate about the future is that there may be 25,000 hospitalists by as soon as 2010, and that the need will plateau with that number, he said.

“I feel that hospital medicine is growing according to Moore's law—the guy who said computers double their power and speed every 18 months,” said Dr. Nelson, director of hospitalist practice at Overlake Hospital Medical Center, Bellevue, Wash.

But this rapid expansion of hospital practice is liable to bring some economic issues to the fore, Dr. Nelson noted.

A concern has been raised that insurance companies will discover that hospitalists have greater liability exposure than office-based physicians.

Perhaps more importantly at this time, many hospitalists are subsidized by a health plan or the hospital where they work because their patient mix tends to include a high proportion of uninsured people.

According to a survey conducted by the Society of Hospital Medicine in 2003, the average hospitalist generates fees of $178,471 a year and receives $74,000 in hospital support, for a total that produces an average income of $158,493 plus $28,776 in benefits, after subtraction of costs and overhead.

As the ranks of hospitalists grow, hospitals may need to wean them off of this support, as happened with emergency department physicians as their specialty developed.

The difference, however, was that emergency physicians were able to have their fees raised and corrected in the era before the imposition of rigid fee caps, Dr. Nelson said. That is not possible anymore.

Another economic challenge is that medicine is adopting global fee structures and pay-for-performance strategies. That may put hospitalists in a particular bind, if hospitals turn to the hospitalists to achieve cost savings while the hospitalists are dependent on the hospitals for their practices.

Also, as the field evolves, hospitalists are going to be pushed to specialize more, or at least to take on responsibilities that they do not often have now.

This is occurring already, and one example is the admission of patients with hypertensive intracerebral hemorrhage, Dr. Nelson said. In some places, neurosurgeons are looking at hospitalists and wondering why they have to admit these patients, when in the vast majority of cases, the management will be medical in the hospital, followed by referral elsewhere.

Moreover, patient deaths are more common in the hospital than in outside practice, which probably means hospitalists should develop more end-of-life expertise.

The vast majority of hospitalists still come from the ranks of internal medicine, but some institutions already have psychiatry, obstetrics, and cardiology hospitalists, Dr. Nelson said. He also noted that in countries such as Germany, hospital and office practice are already largely differentiated.

The specialization of hospitalists is already raising the question of credentialing, Dr. Nelson noted. At this time, hospitalists can and should just be credentialed in their own specialty, he said. The bigger issue, he added, is what to do about hospital credentials for physicians who never go to the hospital anymore.

In his opinion, office-based practitioners can and should still continue to have hospital credentials because knowledge and expertise are not like the technical proficiency needed to perform a particular procedure, for which it has been shown that regular repetition is necessary for competency.

It is a question that hospitals are already asking, Dr. Nelson said. They are also worried about how they will keep doctors loyal to their particular institution, when the doctors no longer go there.

“A lot of people are thinking about ways to keep doctors loyal to a hospital,” he said.

Hospitalist Evolution Raises Questions, Challenges