L'impact des facteurs sociaux sur les dépenses de santé : comment éviter que la recherche de l'efficience ne se fasse au détriment de l'équité et de l'accessibilité aux soins ?

The cream skimming? effect in the insurance sector occurs when the insurer has the possibility to select individuals whose risk-adjusted per capita payment he considers to be above the expected cost level. To avoid this possibility of selection, the public authority has to determine a financing formula which takes account of the several determinants of costs, to create homogeneous payment groups. We consider the cream skimming effect at the hospital level, through the relationship between socio-economic status (SES) and inpatient length of stay. The Belgian hospitals? financing of day of stay is based upon pathologies (APDRG) and age. The omission of SES may be an incentive for hospitals to select its patients. Our data set contains data from 60 Belgian hospitals for the year 1995, i.e. 466, 087 individual observations, with fully comparable explanatory variables such as pathology, age, length of stay and income, and also community- based observations on social isolation and quality of accommodation. We test the incidence of social factors on length of stay controlling for age, pathologies, type of hospital (public or private), occupation rate, and type of exit (death or transfer). The main outcome is that length of stay is decreasing with income, and is positively related to social isolation. Length of stay is also higher for unemployed or retired people, and for benefit-recipients.