Long-term opioid prescribing and healthcare encounters in metastatic cancer: observational population study

Background Although opioids are effective for cancer pain management, long-term use may result in adverse effects which are understudied among patients with metastatic disease. Objectives To describe long-term opioid prescribing among patients with metastatic cancer and investigate how long-term prescribing practices are associated with the incidence of opioid-related hospitalisations and emergency department visits. Methods This retrospective cohort study included all opioid-na & iuml;ve patients diagnosed with solid metastatic cancer in Alberta, Canada from 2004 to 2017 who had >= 1 year of follow-up. Patients were identified and followed using linked administrative health data. Long-term prescribing was defined as receiving a >= 90-day supply of opioids with a <30-day gap in supply within a 180-day period. The incidence rate of opioid-related healthcare encounters was compared based on characteristics of long-term prescribing (timing, dosage, duration and concurrent medications). Results The study included 10 927 patients, 2521 (23%) of whom received long-term opioid prescribing. These practices became more common near the end of life, with 53% of cases initiated during patients' last year of life. Opioid-related healthcare encounters were experienced by 85 (3.4%) recipients of long-term prescribing. Higher dosage (p<0.001) and concurrent prescribing of anxiolytics (p=0.001), benzodiazepines (p=0.001), antidepressants (p=0.027) and neuroleptics (p<0.001) were associated with a higher incidence of opioid-related healthcare encounters. Conclusions Long-term opioid prescribing is common, and patients receiving long-term prescriptions with high dosage or concurrent psychoactive medications may benefit from interventions aimed at reducing opioid-related adverse effects. Further research is needed to determine strategies to minimise opioid-related harms for these patients while providing appropriate pain and symptom management.