HIV disease and the public clinics and programs serving that population. Providers benefit from guaranteed funding of AIDS patients care, and patients benefit from increased access and choice.

Structural barriers to access to the personal health care system have traditionally included lack of a primary source of care, lack of appropriate service providers in one's area, distance from providers, and extended waiting time for providers. In each case, these structural barriers theoretically detract from the patient's ability and willingness to obtain, and then adhere to, appropriate medical care.

Having a regular source of ambulatory care has traditionally been viewed as a sine qua non for access to medical care. Without a regular source of care, it is argued, individuals will not have the benefits of preventive care and periodic checkups. When they do become ill, there will be no one who is sufficiently knowledgeable to make informed clinical decisions about their treatment. National surveys have consistently shown that the 15 percent of the population without a regular source of care are less likely to be insured and to have had recommended screening exams (Hayward et al., 1991).

Although in the general population the proportion of people without a regular source of care is only 15 percent, this figure may be higher among those with HIV disease. In the general population, the groups most likely not to have a regular source of care, men between 18 and 45 and those without insurance, are precisely the groups with HIV disease. An added difficulty in trying to estimate the proportion of HIV-infected people without regular care is the lack of comparability between populations. Because HIV disproportionately strikes those who are underrepresented in national telephone surveys (the method used to ascertain those with a regular source of care), it is improper to extrapolate these national estimates to the HIV population.

Several major issues complicate an understanding of what is and is not a "usual source of care" for persons with HIV disease: (1) the nature of the relationship between nonmedical treatment systems and medical care providers; (2) the role of the hospital clinic and whether, with its rotating staff, it provides the continuity generally associated with a primary care physician; (3) the role of disease progression in stimulating a shift in primary care responsibility from the generalist to the specialist; and (4) the implications of using multiple physicians in the ongoing care of a patient.