231 Does Prescription Opioid Shopping Increase Mortality and Overdose Rates?

Abstract

Prescription opioid shopping is prevalent in emergency department settings. Prescription monitoring and payer “lock-in” programs are increasingly targeting prescription opioid shoppers. However, the link between shopping and overdose events is poorly understood. We studied adult Washington State Medicaid beneficiaries with prescription opioid use in the six months prior to an ambulatory care or emergency department visit with a pain-related diagnosis. The study time frame was Jan 1, 2014 to Dec 31, 2014. We obtained Medicaid claims data linked with controlled substance dispense data from the state prescription monitoring program. The primary outcome was combined all-cause mortality and non-fatal overdose events within six months after the index visit. The exposure of interest (opioid shopping) was defined as having ≥3 prescribers or ≥3 pharmacies in the 6 months prior to the index visit. We used a propensity score to match shoppers with non-shoppers in a 1:1 ratio. The propensity score was calculated based on 40 variables including demographic characteristics, physical and mental health co-morbidities, and measures of prior opioid use. We calculated the absolute difference in outcome rates between shoppers and non-shoppers. We studied 98,684 patients, including 14,701 (14.9%) opioid shoppers. In unadjusted analyses, shoppers had higher event rates than non-shoppers (rate difference of 2.1 events per 1000; 95% CI: 0.8 to 3.5). After 1:1 propensity score matching, there were minimal differences (absolute standardized difference <0.1) between opioid shoppers and matched non-shoppers for all covariates. After propensity score matching, there were no outcome differences between shoppers and non-shoppers (rate difference of -0.7 events per 1000; 95% CI:-3.0 to 1.6). These findings were robust to various definitions of opioid shopping. Prescription opioid shopping is not independently associated with increased risk of death or non-fatal overdose events, and may be a marker of drug diversion. Efforts to improve outcomes among prescription opioid recipients should focus on other validated predictors of overdose risk.