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.