We assessed the effects of opioid dose and risk reduction initiatives on opioid overdose rates among patients on chronic opioid therapy (COT). Using an interrupted time series design, we compared trends in overdose rates. We compared patients on COT in settings that implemented a COT dose reduction initiative and then a COT risk stratification/monitoring initiative to similar patients on COT from control settings. From 2006 to 2014, 31,142 patients on COT (22,673 intervention, 8,469 control) experienced 311 fatal or nonfatal opioid overdoses. In primary analyses, changes in opioid overdose rates among patients on COT did not differ significantly between intervention and control settings with the implementation of either dose reduction or risk stratification/monitoring. In planned secondary analyses, overdose rates decreased significantly (17% per year) during the dose reduction initiative among patients on COT in intervention settings (relative annual change, 0.83; 95% confidence interval, 0.70-0.99), but not in control settings (0.98. 95% confidence interval, 0.70-1.39). We conclude that overdose rates among patients on COT were not decreased by risk stratification and monitoring initiatives. Results were inconsistent for COT dose reduction, with no significant difference between intervention and control settings (primary hypothesis test), but a significant decrease in overdose rates within the intervention setting during dose reduction (secondary hypothesis test). PERSPECTIVE: Risk stratification/monitoring interventions among patients on COT did not decrease opioid overdose rates. The effects of COT dose reduction on opioid overdose rates were inconsistent. Greater decreases in COT dose, a larger control group, or both may have been needed to identify conclusive reductions in opioid overdose rates.
Keywords: Opioids; drug overdose; evaluation; interrupted time series; opioid dose; risk reduction.
Copyright © 2018. Published by Elsevier Inc.