Chronic post‐operative opioid use after open cardiac surgery: A Danish population‐based cohort study

BACKGROUND: Knowledge of chronic opioid use after cardiac surgery is sparse. We therefore aimed to describe the proportion of new chronic post‐operative opioid use after open cardiac surgery. METHODS: We used prospectively registered data from a national prescription registry and a clinical registry of 29 815 first‐time cardiac surgeries from three Danish university hospitals. Data collection spanned from 2003 to 2016. The main outcome was chronic post‐operative opioid use, defined as at least one opioid dispensing in the fourth post‐operative quarter. Data were assessed for patient‐level predictors of chronic post‐operative opioid use, including pre‐operative opioid use, opioid use at discharge, comorbidities, and procedural related variables. RESULTS: The overall proportion of post‐operative opioid use was 10.6% (95% CI: 10.2‐10.9). The proportion of new chronic post‐operative opioid use was 5.7% (95% CI: 5.5‐6.0) among pre‐operative opioid naïve patients. The corresponding proportions among patients, who pre‐operatively used low or high dose opioid (1‐500 mg or > 500 mg cumulative morphine equivalent opioid), were 68.3% (95% CI: 66.1‐70.4) and 76.3% (95% CI: 74.0‐78.5) respectively. Risk factors associated with new chronic post‐operative opioid use included: female gender, underweight and obesity, pre‐operative comorbidities, acute surgery, ICU‐time > 1 day, and post‐operative complications. Strongest predictor of chronic post‐operative opioid use was post‐discharge use of opioid within one month after surgery (odds ratio 3.3, 95% CI: 2.8‐4.0). CONCLUSION: New chronic post‐operative opioid use after open cardiac surgery is common. Focus on post‐discharge opioid use may help clinicians to reduce rates of new chronic opioid users.