In order to stablish the hierarchic order of a regionalized health service system, preliminary studies are needed to give a clear picture of the medical care centers in the region where the users of this aid habitually obtain the medical attention they need. The method presented checks the locale where the death occurred against that of the deceased's residence within a given medical district. It is assumed that the occurrence of deaths outside the city of residence is almost always due to the attempt to get better medical care in another city better provided with health services (except those due to acute events). With this in mind, "the polarization of preference" among centers was studied in one of the Regional Health Divisions in the State of S. Paulo; the information used was the death registrations of 36,448 residents. These registrations were made in 1972, 1974, and 1976 and 3,930 were made in regions other than that of the deceased. The highest rates of "polarization of preference" were scored by cities providing more and better medical facilities. Furthermore, the "natural medical centers" identified in this inquiry coincided with the regional centering provided for and defined by State law.
Medical assistance; Regional medical programs; Mortality