Associations between initial opioid exposure and the likelihood for long-term use.

OBJECTIVES: This study examined the association between initial opioid exposure and subsequent long-term use in 2 national Veterans Administration (VA) cohorts from 2011 and 2016, a period during which opioid prescribing declined.
DESIGN: Two methodologies were used to determine the relationship between initial exposure and subsequent long-term use. SETTING AND PARTICIPANTS: Incident opioid users during 2016 were identified using national VA administrative data. OUTCOME MEASURES: Relationships between days' supply, daily dose, and number of fills within the first 30 days and subsequent long-term opioid use were also examined. All analyses were repeated for an identically derived cohort during 2011.
RESULTS: In 2016, 6.2% (method 1: Deyo replication) or 16.8% (method 2: Shah replication) of incident opioid users progressed to long-term opioid use. In 2011, 14.3% (method 1) or 29.2% (method 2) of incident users progressed to long-term use. Cumulative days' supply emerged as the strongest predictor in a multivariable model of long-term opioid use, which occurred in 1.5% of patients dispensed 7 days' supply or less and in 27.7% of patients dispensed greater than 30 days' supply. Results were similar in the 2011 cohort. Although the relationship between days' supply of incident opioid exposure and long-term opioid use remained consistent over time (in both 2011 and 2016), the overall rate of becoming a long-term opioid user decreased over time across levels of initial exposure.
CONCLUSION: The findings confirm existing literature demonstrating a strong relationship between initial opioid exposure and future likelihood for long-term use. This valuable prognostic information could potentially be leveraged for intervention, including pharmacist-based approaches to prevent progression to long-term opioid use when it is unintended or clinically inappropriate.