The new Institute of Medicine definition of primary care is not vet operational since it is unknown whether its description fits reality. Different primary care clinicians, ie, family physicians, pediatricians, general internists, and nurse practitioners, have different frames of reference, training programs, and views on their involvement in the delivery, of care.Rapid changes in the United States health care system complicate the operationalization of the definition considerably, especially with regard to the central issue of the large majority of personal health care needs.

The episode of care is designated as the unit of assessment for deciding whether a clinician indeed provides care for the large majority of health care needs of persons who consider him or her their usual provider. The term episode of care refers to a health problem from its first encounter with a health care provider through the completion of the last encounter related to that problem.  An episode of care, therefore, differs from an episode of disease, which is a health problem from its onset through its resolution or until the patient’s death, and an episode of illness, which is the period during which a person suffers from symptoms or complaints experienced as an illness. Not every disease and certainly not every illness results in an episode of care. Most episodes of care, however, are part of an episode of disease and, less often, of illness. Health maintenance episodes can be considered a special form of episodes of care.

The prevalence of an episode of care consequently is lower than the prevalence of a given disease in the population. For some diseases, the prevalences will be similar, as with fractures, strokes, metastatic malignancy, and blindness. More often, however, there will be considerable discrepancies between the actual demand for care and the potential need as expressed by data from population studies (disease), from health interviews (illness + disease), and from utilization studies (care). In the United States, the National Ambulatory Medical Care Survey,[10] National Health Interview Survey, and National Medical Expenditure Survey are major sources for such data.

A Core Concept for Family Practice

The episode of care is central to the use of the International Classification of Primary Care (ICPC), developed by the World Organization of Family Doctors. This system is designed to characterize the three essential elements of primary care episodes: the patient’s reason for the encounter, the diagnostic label, and the diagnostic and therapeutic intervention.

The content of primary care has been described in several epidemiologic studies. From these studies, the family doctor emerges as the prime candidate to meet the requirement of dealing with the large majority of personal health care needs. Everyone for whom a family physician is the usual provider of care can present to him or her with any health problem at any stage of development. These problems as distributed represent the large majority of personal health care needs for different sex and age groups and are globally known, in both the United States and elsewhere.

In addition to providing personal continuity of care, family physicians also provide factual continuity of care when they structure and update the medical life histories of their patients over time, taking into account the changes in medicine, in society and in their patients’ lives.

The main goal of this article is to illustrate how the content of family practice can be characterized in an episode-oriented epidemiologic model,

Methods

In the Netherlands, patients cannot seek specialist care without a referral by the family physician. This circumstance allows a rather close approximation of the large majority of personal health care needs. The Dutch health care system, in which family physicians are designated as primary care physicians, differs from that in the United States, where not only family physicians but also general internists, pediatricians, and gynecologists serve as primary care clinicians.

Data on patients enrolled (listed) with a family physician are presented in the form of standard presentations with a 1-year time window (Transition project of the Department of Family Practice, University of Amsterdam). In the period 1985 to 1994, complete data on 236,023 episodes of care during 93,297 patient years were routinely registered and coded by 43 family physicians. Data on episodes of care in women 2 5 to 44 years of age have been selected for use in this paper to provide an indication of the potential involvement of different primary care providers, ic, family physicians, general internists, and gynecologists, in the large majority of the health care needs in this group.