Benzodiazepine use among older adults with chronic obstructive pulmonary disease: a population-based cohort study

Background — Patients with chronic obstructive pulmonary disease (COPD) may receive benzodiazepines for a variety of reasons, including as treatment for insomnia, as treatment for depression and anxiety, and to help relieve refractory dyspnoea. However, benzodiazepines have been linked to adverse physiological respiratory outcomes in individuals with COPD. The potential adverse respiratory effects of benzodiazepines in COPD may also be heightened in older adults given their altered pharmacokinetics that increase benzodiazepine half-life. There is minimal information on the scope and nature of benzodiazepine use in the older adult COPD population.

Objective — The purpose of this study was to describe patterns of benzodiazepine use among older adults with COPD.

Methods — A validated algorithm was applied to Ontario healthcare administrative data to identify older adults with COPD. Incident oral benzodiazepine receipt between 1 April 2004 and 31 March 2009, defined as no benzodiazepines dispensed in the year prior to incident prescription, was examined. Regression techniques were used to identify patient characteristics associated with new benzodiazepine use. Descriptive statistics were performed to describe benzodiazepine use among new users. The analysis was stratified by COPD severity defined by COPD exacerbation frequency (less severe COPD: 0 exacerbations in the year prior; more severe COPD: 1 or more exacerbations in the year prior).

Results — Among 111,445 older adults with COPD, 35,311 (31.7 %) received a new benzodiazepine. New benzodiazepine receipt was higher among individuals with more severe COPD (adjusted odds ratio 1.43, 95 % CI 1.38-1.48). Among new benzodiazepine users, there was a relatively high frequency of receipt of long-acting agents (14.6 %), dispensations for greater than 30 days (32.6 %), second dispensations (22.0 % or 30.6 % for occurrence within 120 % or 200 % days of the index prescription, respectively), early refills (11.6 %), and benzodiazepine receipt during COPD exacerbations (9.0 %). Among individuals with more severe COPD, 35.4 % of incident use occurred during a COPD exacerbation.

Conclusions — Almost one-third of older individuals with COPD received a new benzodiazepine, and rates were higher among those with more severe COPD. Important safety and quality of care issues are potentially raised by the degree and pattern of benzodiazepine use in this older and respiratory-vulnerable population.