Patient socioeconomic determinants of the choice of generic versus brand name drugs in the context of a reference price system: evidence from Belgian prescription data

The generic reference price system (RPS) can impose a financial penalty for patients using a brand name drug instead of its generic alternative. Previous studies on the impact of the RPS have not considered the potentially differential effect of using generic alternatives for individuals with a different socioeconomic background. However, patients' characteristics might determine their overall knowledge of the existence of the system and thus of the financial burden to which they may be confronted. The association between patients' characteristics and the use of generic drugs versus brand name drugs was analyzed for ten highly prescribed pharmaceutical molecules included in the Belgian generic reference price system. Prescriptions were obtained from a 10% sample of all general practitioners in 2008 (corresponding to 120,670 adult patients and 368,101 prescriptions). For each pharmaceutical molecule, logistic regression models were performed, with independent variables for patient socioeconomic background at the individual level (work status, having a guaranteed income and being entitled to increased reimbursement of co-payments) and at the level of the neighborhood (education). The percentage of generic prescriptions ranged from 24.7 to 76.4%, and the mean reference supplement in 2008 ranged from a,not sign4.3 to a,not sign37.8. For seven molecules, higher use of a generic alternative was associated with either having a guaranteed income, with receiving increased reimbursement of co-payments or with living in areas with the lowest levels of education. Globally, results provided evidence that the generic RPS in Belgium does not lead to a higher financial burden on individuals from a low socioeconomic background