Hospital medicine
Hospital medicine in the United States is the discipline concerned with the general medical care of hospitalized patients. Doctors, Physician Assistants or Nurse Practitioners whose primary professional focus is hospital medicine are called hospitalists; this type of medical practice has extended beyond the US into Canada.  The term "hospitalist" was first used by Dr. Robert Wachter in a 1996 New England Journal of Medicine article.  Hospitalist activities may include patient care, teaching, research, and leadership related to hospital care.  Hospital medicine, like emergency medicine, is a specialty organized around a site of care (the hospital), rather than an organ (like cardiology), a disease (like oncology), or a patients age (like pediatrics). However, unlike medical specialists in the emergency department or critical care units, most hospitalists help manage patients throughout the continuum of hospital care, often seeing patients in the ER, admitting them to inpatient wards, following them as necessary into the critical care unit, and organizing post-acute care.

# Training
The majority of hospitalists are physicians with a Doctor of Osteopathic Medicine (D.O.) or Medical Degree (M.D.). About 78% of practicing hospitalists are trained in general internal medicine. Another 4 % are trained in an internal medicine subspecialty, most commonly pulmonology or intensive care medicine. About 3 % of hospitalists are trained in family practice; about 8 % are pediatricians and 2 % are trained as med-peds (training in internal medicine and pediatrics). The remaining 5 % of hospitalists are non-physician providers, usually nurse practitioners and physician assistants.
While it was commonly believed that any residency program with a heavy inpatient component provided good hospitalist training, studies have found that general residency training is inadequate because common hospitalist problems like neurology, hospice and palliative care, consultative medicine, and quality assurance tend to be glossed over. To address this, residency programs are starting to develop hospitalist tracks with more tailored education.  Several universities have also started fellowship programs specifically geared toward hospitalist medicine.

# History
Hospital medicine is a relatively new phenomenon in American medicine. Almost unheard of a generation ago, this type of practice arose from three powerful shifts in medical practice:
- Nearly all states, as well as the national residency accreditation organizations, the Accreditation Council for Graduate Medical Education (ACGME) and the American Osteopathic Association (AOA), have established limitations on house staff duty hours, the number of hours that interns and residents can work.  This effectively reduces by 10-25% the amount of inpatient coverage provided per.  Many hospitalists are coming to perform the same tasks formerly performed by residents.
- Most primary care physicians are experiencing a shrinking role in hospital care. Many primary care physicians find they can generate more revenue in the office during the hour or more they would have spent on inpatient rounds, including traveling to and from the hospital. Furthermore, the increasingly specialized care provided in the hospital makes it difficult for primary care physicians to keep abreast of developments.  Finally, fewer physicians are establishing solo practices; if one physician of a large group is delegated to make hospital rounds, most of the patients have already lost their familiar contact.
- With strong pressure to decrease inpatient length of stay, coupled with the increasing severity of illness of hospitalized patients required to justify admission, hospitalists are able to provide the increasingly necessary continual on-site availability.  It has become significantly more difficult for an office-based physician to effectively direct this.
Hospitalists represent one of the most rapidly growing forms of medical practice in the US. Currently a large proportion of hospitalists are recently-graduated residents, who continue familiar duties for a few years. As residency programs are encouraged to limit inpatient duty hours and provide more outpatient education, this pattern may shift. If this specialty evolves as emergency and intensive care medicine did, it will become a formal speciality with its own residencies and board certification within a decade or two. A few distinct residency and fellowship training programs are currently operating at major universities.
In addition to patient care duties, hospitalists are often involved in developing and managing aspects of hospital operations such as inpatient flow and quality assurance. The formation of hospitalist training tracks in residency programs has been driven in part by the need to educate future hospitalists about business and operational aspects of medicine, as these topics are not covered in traditional residencies.