The survey, published in the December issue of the Journal of General Internal Medicine, also found that specialists have fewer numbers of Medicaid patients in their practices than do primary care doctors and that most doctors hold negative views of Medicaid patients.

"The Medicaid program has improved access to care for low-income patients who would otherwise lack health insurance," says lead author Lisa Backus, M.D., Ph.D., of the University of California, San Francisco. "However, many physicians do not participate in Medicaid, limiting the effectiveness of Medicaid in enhancing access to care."

Backus and colleagues sent surveys to primary care and specialist physicians practicing in the 13 largest urban counties in California. These counties contain approximately 80 percent of the state's population, Medicaid population and practicing specialists.

Questionnaires were filled out by 978 of the 1,492 eligible specialists. The surveyed physicians specialized in cardiology, endocrinology, gastroenterology, general surgery, neurology, ophthalmology and orthopedics.

Out of 876 primary care physicians who met the study's requirements, 713 returned the questionnaire. Areas of practice included family practice, general practice, general internal medicine, general pediatrics and obstetrics and gynecology.

Both 56 percent of the specialists and 56 percent of the primary care physicians reported that they treated Medicaid patients. However, among those physicians, Medicaid patients comprised an average of 12 percent of the specialists' patients compared to 20 percent for the primary care physicians.

Although 55 percent of the specialists were accepting new Medicaid patients compared to 49 percent of the primary care physicians, the specialists were more interested in seeing fee-for-service Medicaid patients. Only 62 percent of the specialists who were accepting new Medicaid patients would accept those who were in managed care, compared to 80 percent of the primary care physicians who were accepting new Medicaid patients.

Some physicians, particularly doctors who were African-American, Latino or Asian or who worked in group-model health maintenance organizations, were more likely to treat Medicaid patients.

Both the specialists and the primary care physicians held negative opinions about Medicaid patients. Almost three-quarters of all the physicians thought that Medicaid patients tended to have complex clinical and psychological problems, were noncompliant and required more time to treat. Specialists also thought that Medicaid patients were more likely to sue for malpractice.

"Our research indicates that the adoption of Medicaid managed care could have differential effects on specialist and primary care physicians' participation in Medicaid, which would result in decreased access to specialists for Medicaid managed care patients," says Backus.

"This decrease in access [to specialists] may be mitigated if states are able to contract with group model HMOs and to recruit minority physicians."

This study was funded by grants from the AHDCP, the California Program on Access to Care, the HRSA Bureau of Health Profession and a Robert Wood Generalist Physician Faculty Scholar Award.

The Journal of General Internal Medicine, a monthly peer-reviewed journal of the Society of General Internal Medicine, publishes original articles on research and education in primary care. For information about the journal, contact Renee F. Wilson at (410) 955-9868.