[Exploration of the determining factors of costs in a health sector]

The study is about the variability of expenses between different village of the administrative division of ICS (Health Catalan Institute), and the influence are over this variations who have the indicative factors of accessibility and needs. The used design is ecologic, and the statistic unit for the study is the people treated by the same physician. We used two models of multiple regression and study the relation among variables with pharmaceutic expenses and derivation (hospitalization level), that means 30% and 50% respectively of the whole cost. In the pharmaceutic expenses, the distance and elderly are the factors that better explains the variability. In the derivation expenses the explication factor is the number of people by physician. The offer of and access to health services and determinants of their utilization. The discussion is about this results with the concepts of supply and need, as well as about some limitations of the study.