Long-term continuous use of benzodiazepines by older adults in Quebec: prevalence, incidence and risk factors.

Objective: To determine the prevalence and incidence of long-term use of benzodiazepines and to assess patient-, prescriber-, and drug-related risk factors.
Design: Cohort study.
Participants: 1,423 community-dwelling older adults in Quebec who participated in the Canadian Study of Health and Aging (CSHA1).
Measurements: Patient characteristics were obtained from the CSHA1 database. These were linked to provincial health insurance data to ascertain benzodiazepine use and prescriber characteristics.
Main Outcome Measure: Use of benzodiazepines for at least 135 of the first 180 days following initiation of use.
Results: Twelve-month prevalence of long-term continuous use, standardized by age and gender to the Quebec population, was 19.8%. Twelve-month cumulative incidence of long-term continuous use was 1.9%. Older patients were more likely to proceed to long-term continuous use.
Conclusions: Risk of long-term continuous use of benzodiazepines seems to increase with age. This association was found to be independent of gender, health status, anxiety, cognitive status, benzodiazepine type, and physician characteristics.