AN INVESTIGATION OF THE REPRESENTATIVITY OF NEUROPSYCHIATRISTS AND THEIR PATIENTS IN A DRUG UTILIZATION OBSERVATION STUDY ON FLUOXETINE

This study presents a methodological approach to an ex post facto inve stigation of sample bias in drug utilization observation (DUG) studies using the example of a DUO with the nontricyclic antidepressantfluoxe tine. A total of 479 psychiatrists and neurologists and 2,401 patients were investigated. The purpose of the study was to judge the represen tativeness of our DUO sample for two populations: first, for all psych iatries and neurologists prescribing fluoxetine or all patients being treated with fluoxetine in Germany and, second,for all psychiatrists a nd neurologists prescribing antidepressants or all patients being trea ted with antidepressants in Germany. Criteria for the representativene ss test were physician variables (gender, size of community where prac ticing, federal state, age, Volume of prescriptions) and patient varia bles (gender, age, prescription-related diagnosis, concurrent illnesse s, concomitant medications). The study shows that the DUO sample can r ightfully claim representativeness in the majority of parameters for t he psychiatrists and neurologists prescribing fluoxetine and for the p atients being treated with fluoxetine. There are more noticeable discr epancies with regard to the psychiatrists and neurologists in general and to the patients being treated with antidepressants in general. The methodological problems of pharmacoepidemiological investigation of r epresentativeness are discussed.