[Explanatory variables of avoidable cost produced by not prescribing a cheaper equivalent drug]

To identify the explanatory variables of avoidable cost produced by not prescribing a cheaper equivalent drug.

We conducted a cross-sectional study of 1,500 primary care physicians in Galicia (northwest Spain). The sample consisted of 405 primary care physicians. The following independent variables were collected through a postal questionnaire physicians' training and specialty, physicians' perception of the quality of available drug information sources, type of practice, and number of patients. The environmental characteristics of the practice were obtained from secondary sources. Multiple regression models were constructed using as dependent variables two indicators based on unnecessary cost produced by not prescribing cheaper equivalents.

The response rate was 77,4%. No association was found between prescription efficiency and the level of the physician's training, or with the variables of utilization or the quality of commercial and institutional information. The variable of health model was not significant. The only statistically significant variables were the number of identification cards and the percentage of pensioners' identification cards.

The results of this study suggest that physicians attach little importance to prescription efficiency. Thus, to decrease avoidable cost produced by not prescribing a cheaper equivalent drug, the medical curriculum should be modified to ensure that is contents reflect national health priorities and current resources.