This study deals with the analysis of the factors associated with drug utilization and is therefore a pharmacoepidemiology study and, specifically, a drug utilization study (DUS)1.

Although abundant literature on the subject has been published, each new study in this field contributes complementary information, specific to the population studied, since a large proportion of the factors determining drug utilization are sociodemographic; consequently, these studies generally have little external validity.

In the present study, the patients were recruited from health centers and their characteristics, as well as data on drug utilization, were gathered through a questionnaire. Although constructing a primary database can confer researchers with greater freedom and allow the variables gathered specifically for the study to be studied, the potential of secondary sources such as the National Health Survey or the Pharmaceutical Billing Database2, the latter in combination with the Health Identification Card, should not be underestimated. In addition to efficiency, both databases are representative of the population in a way that is difficult to achieve in databases generated specifically for a particular study.

However, secondary databases also present major limitations. Pharmaceutical Billing Databases, for example, do not contain information on the indication motivating the drug prescription, making studies of indication-prescription and prescription-indication impossible2. And these are, in our opinion, precisely the designs currently required in DUS in Spain.

The Database for Pharmacoepidemiological Research in Primary Care1 of the Spanish Medication Agency, which includes the participation of 10 autonomous communities and approximately 1,000 physicians, integrates data on signs and symptoms, diagnosis, indication and prescription, in addition to patient characteristics. In the next few years, this database will allow major advances to be made in the DUS performed in primary care.

Importantly, the efficacy of this database will be determined by its accessibility to the distinct research groups. The Spanish Medication Agency should approve the conditions for its use by researchers as soon as possible.