The impact of a primary care physician cooperative on the caseload of an emergency department: the Maastricht integrated out-of-hours service.

OBJECTIVE: To determine the effect of an out-of-hours primary care physician (PCP) cooperative on the caseload at the emergency department (ED) and to study characteristics of patients utilizing out-of-hours care.

DESIGN: A pre-post intervention design was used. During a 3-week period before and a 3-week period after establishing the PCP cooperative, all patient records with out-of-hours primary and emergency care were analyzed.

SETTING: Primary care in Maastricht (the Netherlands) is delivered by 59 PCPs. Primary care physicians formerly organized out-of-hours care in small locum groups. In January 2000, out-of-hours primary care was reorganized, and a PCP cooperative was established. This cooperative is located at the ED of the University Hospital Maastricht, the city's only hospital, which has no emergency medicine specialists.

MAIN OUTCOME MEASURES: The number of patients utilizing out-of-hours care, their age and sex, diagnoses, post-ED care, and serious adverse events.

RESULTS: After establishing the PCP cooperative, the proportion of patients utilizing emergency care decreased by 53%, and the proportion of patients utilizing primary care increased by 25%. The shift was the largest for patients with musculoskeletal disorders or skin problems. There were fewer hospital admissions, and fewer subsequent referrals to the patient's own PCP and medical specialists. No substantial change in new outpatient visits at the hospital or in mortality occurred.

CONCLUSIONS: In the city of Maastricht, the Netherlands, the PCP cooperative reduced the use of hospital emergency care during out-of-hours care.