Correlates of Benzodiazepine Use and Adverse Outcomes Among Patients with Chronic Pain Prescribed Long-term Opioid Therapy

Objective. To examine the correlates and odds of receiving overlapping benzodiazepine and opioid prescriptions and whether co-prescription was associated with greater odds of falling or visiting the emergency department. Design. Cross-sectional study. Setting. A large private integrated health system and a Veterans Health Administration integrated health system. Subjects. Five hundred seventeen adults with musculoskeletal pain and current prescriptions for long-term opioid therapy. Methods. A multivariate logistic regression model examined correlates of having overlapping benzodiazepine and opioid prescriptions in the year before enrollment in the cross-sectional study. Negative binomial models analyzed the number of falls in the past three months and past-year emergency department visits. In addition to propensity score adjustment, models controlled for demographic characteristics, psychiatric diagnoses, medications, overall comorbidity score, and opioid morphine equivalent dose. Results. Twenty-five percent (N =127) of participants had co-occurring benzodiazepine and opioid prescriptions in the prior year. Odds of receiving a benzodiazepine prescription were significantly higher among patients with the following psychiatric diagnoses: anxiety disorder (adjusted odds ratio [AOR] = 4.71, 95% confidence interval [CI] - 2.67-8.32, P< 0.001), post-traumatic stress disorder (AOR = 2.24, 95%CI = 1.14-4.38, P=0.019), and bipolar disorder (AOR = 3.82, 95% CI =1.49-9.81, P=0.005). Past-year overlapping benzodiazepine and opioid prescriptions were associated with adverse outcomes, including a greater number of falls (risk ratio [RR] = 3.27, 95% CI= 1.77-6.02, P=0.001) and emergency department visits (RR = 1.66, 95% CI = 1.08-2.53, P= 0.0194). Conclusions. Among patients with chronic pain prescribed long-term opioid therapy, one-quarter of patients had co-occurring prescriptions for benzodiazepines, and dual use was associated with increased odds of falls and emergency department visits.