Abstract
OBJECTIVE: Identification of the variables relative to the population characteristics and the primary and specialised care services provision which determine the referral rates between both levels. DESIGN: Cross-sectional ecological study. SETTING: Basic health zones (BHZ) of the Community of Madrid (CAM), Spain, 2001. PARTICIPANTS: Population of the CAM. MAIN MEASUREMENTS: Dependent variable: population referral rate (PRR) (referrals per BHZ in 2001 divided by BHZ population). INDEPENDENT VARIABLES: population and their characteristics (income, unemployment, educational level, elderly and dependence level, marital status, immigrant rates); need of services (care frequency index and standardised mortality rate); primary care provision characteristics (number of doctors, distribution by age and sex, organisational model, number of years in primary care; specialised care provision characteristics (number of laboratory specialists, ratio of radio-diagnostic and clinical services doctors). RESULTS: The average PRR is 31.9 (0.87) per 100 inhabitants, with a tendency for similar values to group into three clusters. Five components which explain 81.87% of the variation have been identified: total population, demographic characteristics, socioeconomic status, need of services, and social mobility. In the regression analysis (R2=0.18), the last 3 reach statistical significance. CONCLUSIONS: The PRR is greater in the BHZ with higher levels of need of services and lower levels of socioeconomic status and social mobility. There is no relationship with either the provision or the organisation of primary care and specialised care. These variables should be included in the planning of the provision of services.