Prescribed daily doses and 'risk factors' associated with the use of benzodiazepines in primary care

Objective - To assess the extent, characteristics and determinants of benzo diazepine prescription in outpatient Primary Health Care. Methods - A clinical audit of a stratified random sample of Primary Health Care Centres in the seven islands and 1.6 million inhabitants region of 'Ca narias' in Spain was carried out. From those centres, a random sample of 10 45 clinical records was reviewed and information on diagnosis, prescription and prescribed dosages was collected in a structured questionnaire. A mult ivariate logistic regression analysis was performed in order to determine t he 'risk: factors' for the use of benzodiazepines. Results - Benzodiazepine prescription was recorded in 23.4% of all clinical records; 87.7% of these were for benzodiazepines classified as anxiolytics (N05B) and 12.3% for hypnotics (N05C2). Benzodiazepine prescription was mo re common for women, elderly, widowed, divorced, low educational background , housewives and retired people. Using multivariate logistic regression, th e probability of benzodiazepine prescription was found to be closely relate d to age, gender and employment status, but not with educational level. Pre scribed Daily Doses were lower than Defined Daily Doses (DDD) in 77.1% of a ll anxiolytic prescriptions, but were in agreement with DDD in 90% of hypno tic prescriptions. The duration of treatment recorded in the clinical recor ds was 25 +/- 21 months, with a range of 1 and 144 months. General Practiti oners were responsible for 67% of all benzodiazepine prescription. Anxiolyt ics were prescribed as a single daily dose in 57% of the cases, and only 'a t supper' in 48.6%. Conclusion - Tn the general population attending Primary Health Care Centre s of the Canary Islands Health System the prescription of benzodiazepines i s higher for women and the elderly, and the most common use is chronic, wit h a duration of over 2 years in most cases. Anxiolytics are prescribed in d oses which are much lower than those used as DDD and were used only 'at nig ht' in almost half of the cases. This could represent an overlapping of the indications with hypnotics, and explain part of the huge difference in the use of anxiolytics in Spain compared with other figures in Europe. This fa ct must also be taken into account when making inferences of benzodiazepine use from sales statistics, which are very imprecise measures of drug use. Copyright (C) 1999 John Wiley & Sons, Ltd.