[Comparative study at 4 health centres of efficiency, measured on the basis of ambulatory care groups].

Objective: To measure efficiency in the use of resources for the care lists of four primary care centres (PCC), by using ambulatory care Groups (ACGs).

Design: Retrospective, observational study.

Setting: Four PC teams.

Participants: All patients attended during 2003.

Measurements: Dependent variables (costs per patient, between medical lists [family medicine, paediatrics] and PCCs) and case load variables. The model of costs for each patient was set by differentiating the semi-fixed and variable costs. The efficiency index (EI) was set as the quotient between the observed real cost and the expected cost on the basis of ACG distribution, by indirect standardization. The study population was 62,311 patients seen, with an average of 4.8+/-3.2 episodes/patient/year.

Main Results: The total health care cost reached 24,135,236.62 euro, of which 65.2% was for prescription, 28.9% for semi-fixed costs, and 2.9% for cost of specialist referrals. The average total cost per patient/year was 387.34 euro+/-145.87 euro (average relative weight). The EI for each centre was: 0.93 (95% CI, 0.85-1.01), 0.97 (95% CI, 0.89-1.05), 1.04 (95% CI, 0.96-1.12), and 1.05 (95% CI, 0.97-1.13), P < .0001. In addition, differences between the medical lists (rank, 0.63-1.56) and between the paediatrics lists (rank, 0.73-1.26) were found (P = .005).

Conclusions: The ACGs enabled us to estimate the efficiency of our PCCs and care lists. Efficiency cannot be isolated from other dimensions of the quality of health care delivery. Study of the EI improved our understanding of the profile of professionals and health centres.