Benzodiazepine-opioid co-prescribing in a national probability sample of ED encounters.

BACKGROUND: Benzodiazepine-opioid combination therapy is potentially harmful due to the risk of synergistic respiratory depression, and the rate of death due to benzodiazepine-opioid overdose is increasing. Little is known about the prevalence and characteristics of benzodiazepine-opioid co-prescribing from the ED setting.

METHODS: Secondary analysis of data from the National Hospital Ambulatory Medical Care Survey, using sample weights to generate population estimates. The primary objective was to describe the annual prevalence of benzodiazepine-opioid co-prescribing from 2006 to 2012, using 95% confidence intervals (95% CI) to compare adjacent years. The secondary objective was to compare characteristics of ED encounters receiving a benzodiazepine-opioid co-prescription versus those receiving an opioid prescription alone, using a multivariable logistic regression.

RESULTS: The prevalence of benzodiazepine-opioid co-prescribing did not significantly change from 2006 to 2012. During this period, 2.7% (95% CI: 2.5-2.8%) of ED encounters prescribed an opioid were also prescribed a benzodiazepine. Relative to encounters receiving an opioid prescription alone, encounters receiving a co-prescription were more likely to represent a follow-up rather than initial visit (Odds Ratio [OR] 1.52), receive more medications (OR 1.41) and fewer procedures (OR 0.48) while in the ED, and more likely to have a diagnosis related to mental disorder (OR 20.60) or musculoskeletal problem (OR 3.71).

CONCLUSIONS: From 2006 to 2012, almost 3% of all ED encounters receiving an opioid prescription also received a benzodiazepine co-prescription. The odds of benzodiazepine-opioid co-prescribing were significantly higher in ED encounters representing a follow-up visit and in diagnoses relating to a mental disorder or musculoskeletal problem.