Abstracts Biological Sciences

Less than optimal uses of benzodiazepines by older adults in Quebec

by Mary Yvonne. Egan

Use of benzodiazepines outside of recommended guidelines for older adults is associated with adverse outcomes. Such "less than optimal use" includes use of long-acting benzodiazepines, use of high daily doses and long-term continuous use. Most previous research on factors associated with these types of use has been carried out using administrative databases containing limited patient information. The objectives of this study were to assess the extent of these less than optimal uses among Quebec seniors and to evaluate the effects of patient and prescriber factors through examination of a research data base containing patient characteristics linked to an administrative data base containing prescription drug records. Study subjects were 1423 community-dwelling Quebec adults age 66 and older who participated in the first phase of the Canadian Study of Health and Aging (CSHA1). Demographic and health data from CSHA1 were linked to prescriptions billed to the Regie de l'assurance maladie du Quebec (RAMQ). One hundred and eighty-two (12.8%) subjects filled at least one prescription for a long-acting benzodiazepine within 365 days following CSHA1 screening (standardized one-year period prevalence 12.4%). Use of long-acting benzodiazepines was associated with male patient gender, earlier physician graduation and physician specialty status. In addition, relationships between use of long-acting benzodiazepines and physician factors were modified by patient anxiety. One hundred and eight subjects (7.6%) filled at least one high dose prescription (standardized one-year prevalence 7.9%). High dose use was associated with patient age and anxiety. Physician specialist status was a risk factor for use of high daily doses among subjects with cognitive impairment but a protective factor among subjects without cognitive impairment. The standardized one-year prevalence of long-term continuous use was 19.8% The one-year cumulative incidence of initiation of such use was 1.9%. Long-term continuous use was associated with increasing age. This study confirmed that these three less than optimal uses of benzodiazepines occur relatively frequently among community-dwelling Quebec seniors. Both patient and prescriber determinants appear to play a role in such use, and patient factors may alter the relationship between less than optimal use and prescriber characteristics.