PATTERNS OF AMBULATORY CARE FOR AIDS PATIENTS, AND ASSOCIATION WITH EMERGENCY ROOM USE

Objective. We examined the association of patterns of ambulatory care for AIDS patients with any use of the emergency room (ER) and the mont hly rate of ER visits in the six months after AIDS diagnosis. Data Sou rces/Study Setting. The study population was obtained from the New Yor k State Medicaid HIV/AIDS Research Data Base and includes patients dia gnosed with AIDS from 1983 to 1990. Data Collection/Extraction Methods . To examine patterns of care and ER use not leading to hospitalizatio n, we studied patients who survived at least six months after their fi rst AIDS-defining diagnosis. The data noise included person level info rmation on visits to different provider sites and patient demographic and clinical characteristics. Study Design. We defined the dominant pr ovider as the site delivering the majority of ambulatory care for pati ents with a minimum of four ambulatory visits in the six months after AIDS diagnosis. Dominant providers were classified by specialty and se tting: generalist physician; general medicine clinic; AIDS specialty c linic; and other specialty clinic or physician (e.g., cardiology). Pat ients without a dominant provider were grouped into those with four or more visits and those with fewer than four visits. Regression analysi s was used to estimate relationships between ER use and patterns of am bulatory care and patient demographic and severity of illness characte ristics. Principal Results. The study population included 9,155 AIDS p atients aged 13 to 60 years at diagnosis, continuously Medicaid-enroll ed, and surviving at least six months after AIDS diagnosis. Among thos e with four or more visits (56 percent), over 70 percent had a dominan t provider. Overall, 39 percent of the study population visited the ER while, in the group with four or more visits, 53 percent of those wit hout a dominant provider had an ER visit. Patients without a dominant provider were estimated to have 32 percent higher odds of ER use than patients with a dominant provider. Among patients with a dominant prov ider, patients with a generalist or primary care clinic dominant site of care were estimated respectively to have 18 percent and 23 percent lower odds than patients with an AIDS specialty clinic as the dominant site of care. Drug users had higher odds of ER use, as did women. Con clusions. In this Medicaid AIDS population, a dominant provider delive ring the majority of a patient's care was associated with less use of the ER by the patient. Among patients with a dominant provider, ER use was lowest for those with a primary care provider. Further examinatio n of the type and availability of ambulatory services in AIDS specialt y clinics and primary care settings, as well as more detailed informat ion on patient characteristics, may reveal reasons for these patterns of ER use.