Prescription monitoring programs and emergency department visits involving benzodiazepine misuse: Early evidence from 11 United States metropolitan areas

Background: Emergency department (ED) visits involving benzodiazepines have increased in the United States. Most states have created prescription monitoring programs (PMPs) to improve drug prescribing safety. To determine the association between PMP implementation and ED visits involving benzodiazepine misuse, we conducted a retrospective analysis of data from 11 metropolitan areas in the United States from 2004 to 2011. Methods: We estimated rates of ED visits per 100,000 residents involving benzodiazepine misuse from the Drug Abuse Warning Network dataset. Dates of PMP implementation were obtained from program administrators. We used linear regression models to assess whether PMP implementation was associated with a change in ED visits involving benzodiazepines. Models were adjusted for calendar quarter, metropolitan area, and metropolitan area-specific linear time trends. Results: Rates of ED visits involving benzodiazepine misuse increased in all metropolitan areas during the study period. PMP implementation was not associated with a change in ED visits (mean difference: 0.9 [95% CI: -0.09 to 1.9] visits per 100,000 population per quarter; p = 0.08). When analyzed by number of years after implementation, PMPs were associated with a higher visit rate in year one (0.8 [95% CI: 0.2-1.5]; p = 0.01]), but not in year two (0.3 [95% CI: -2.1-2.8]; p = 0.78) or year three or later (2.1 [95% CI: -0.4-4.7]; p = 0.10). Conclusion: We did not find evidence that PMP implementation was associated with reductions in ED visits involving benzodiazepine misuse. Future work should identify PMP features and capabilities that improve benzodiazepine safety.