Drug compliance and unreported drugs in the elderly.

A random sample of 46 general practitioners of the Unitá Sanitaria Locale in Torino recruited 802 elderly outpatients and collected information about complaints and current drug treatment. Within a week each patient received a home interview and details were collected on drug compliance and use of drugs other than those reported by the general practitioners. On average, each patient was taking 3.6 drugs, of which 2.9 were correctly reported by the general practitioners and 0.7 were unreported. Among the most prescribed therapeutic groups there were drugs with a narrow therapeutic index (cardiovascular drugs, diuretics, psychotropic agents) and substances whose efficacy has never been fully documented ("cerebroactive-vasoactive" agents). Age and number of complaints were positively and significantly correlated with number of prescribed drugs. Nearly half of the sample (44.4%)--more frequently women and people with higher education--were taking one or more drugs not detected by the general practitioners, often benzodiazepines taken over a long period for anxiety or insomnia. Full compliance occurred for 81.5% of the prescriptions and 59.9% of patients were correctly taking all prescribed drugs. Compliance was lower for prescriptions of the general practitioners compared with other doctors' prescriptions (eg, hospital doctor, private doctor) and probability of taking correctly all the prescribed drugs decreased with the number of medicines concurrently taken. The most common reason for noncompliance was fear of side effects.