Background: Little is known about the patterns, factors, and public health outcomes associated with concurrent utilization of gabapentin, opioids, and benzodiazepines (GABA+OP+BZD)

Objective: To examine the patterns, factors, and public health outcomes associated with concurrent utilization of GABA+OP+BZD among Social Security Disability Insurance (SSDI) eligible beneficiaries. Methods: Using a 5% sample of 2013-2016 Medicare data, we utilized a retrospective cohort design to examine the following patterns of concurrent utilization: monotherapy, dual therapy, tri-therapy, switching, augmentation, discontinuation, and continuation. Similarly, a retrospective cohort design was utilized to examine the sociodemographic and clinical factors associated with the longest concurrent medication utilization episode, defined based on the overlap of prescriptions for GABA+OP+BZD. We used a nested case control design to examine the association between concurrent utilization of GABA+OP+BZD and adverse outcomes (respiratory depression, substance and opioid related overdose, and adverse drug-related events) among disabled beneficiaries with acute pain [AP], chronic pain [CP], and mental health conditions [MH].

Results: Among disabled beneficiaries, gabapentin initiators were significantly more likely to become dual and tri-therapy users (p<0.01) and to augment therapy (50.1%) when compared to opioid (28.7%) and benzodiazepine (38.7%) users; the majority augmented within 2-months after initiating therapy. Back pain [AOR(95%CI): 1.23(1.07-1.41)], chronic pain [1.27 (1.07-1.51)], mental health [1.16 (1.02-1.33)], opioid dose [1.05 (1.03-1.06)] and duration [1.07 (1.06-1.07)], and benzodiazepine duration [1.06 (1.05-1.06)] were positive predictors of having longest concurrent use involving GABA+OP+BZD. Concurrent GABA+OP+BZD use was associated with increased odds of respiratory depression [AP: 1.35 (1.19-1.52), CP:1.24 (1.11-1.38) and MH: 1.16 (1.02-1.32)], opioid related overdose [AP: 1.43 (1.04-1.98), CP: 1.47 (1.07-2.00) and MH: 1.44 (1.04-2.00)], substance related overdose[AP: 1.77 (1.26-2.50), CP: 1.70 (1.24-2.34) and MH: 1.92 (1.31-2.82)] and adverse drug related events[AP: 1.36 (1.22-1.50), CP: 1.23 (1.10-1.36) and MH: 1.15 (1.02-1.30)].

Conclusion: Our study provides the first evidence of patterns, factors, and outcomes associated with concurrent utilization of GABA+OP+BZD. Given noted adverse outcomes associated with GABA+OP+BZD, it is imperative that the benefits and risks of co-prescribing these medications be examined comprehensively, especially for those at the greatest risk of being prescribed these medications.