Long-term use of prescription opioids for non-cancer pain and mortality: a population-based, propensity-weighted cohort study.

ABSTRACT

OBJECTIVE: The objective of this study was to identify factors associated with long-term opioid use and to assess the association between long-term use and death. STUDY DESIGN: Retrospective cohort study combining several population-wide databases and covering a population of five million inhabitants, including all adults who were initiated on opioid treatment from 2014 to 2018 for non-cancer pain. METHODS: We used logistic regression models to identify factors associated with chronic opioid use and carried out survival analyses using multivariable Cox regression modelling for all-cause mortality during follow-up using inverse probability of treatment weighting (IPTW) and propensity scores based on the probability of using opioids chronically. RESULTS: Among 760,006 patients, 82,423 (10.85%) used opioids for 90 days or more after initiation. Initial therapy characteristics associated with higher risk for long-term use were initiating with long- and short-acting opioids (when compared to tramadol, odds ratio [OR] 2.63, 95% confidence interval [CI] 2.57, 2.69 and OR 1.60, 95%CI 1.46, 1.76, respectively), using higher daily doses (when compared to 50 morphine milligramme equivalent [MME] or less, prescribing 50 to 89 daily MME, OR 1.76, 95%CI 1.65, 1.87; 90 to 119 daily MME, OR 2.44, 95%CI 1.99, 3.01; and more than 120 daily MME, OR 1.77, 95%CI 1.64, 1.91), and overlapping with gabapentinoids (OR 2.26, 95%CI 2.20, 2.32), benzodiazepines (OR 1.32, 95%CI 1.30, 1.35), and antipsychotics (OR 1.21, 95%CI 1.16, 1.26). After IPTW, chronic opioid use was associated with higher risk of all-cause mortality when compared to short-term use (Hazard Ratio (HR) 1.37, 95%CI 1.32, 1.42). Sensitivity analyses provided similar results. CONCLUSION: These findings may help healthcare managers to identify and address patients at higher risk of long-term use and riskier prescription patterns.