Persistent prescription opioid use and all-cause mortality following the first-year breast cancer survivorship

BACKGROUND: Harm associated with persistent opioid use beyond the first-year intensive cancer treatment is underinvestigated in cancer survivors. We examined rates and risk factors for persistent opioid use and all-cause mortality after the first-year breast cancer survivorship. METHODS: This retrospective cohort study used electronic health record data from Kaiser Permanente Southern California for women diagnosed with a nonmetastatic breast cancer between 2009 and 2019 who filled 2 or more opioid prescriptions. Rates of persistent opioid use were estimated from first-year survivorship through December 31, 2021. Rate ratios (RRs) and 95% confidence intervals (CIs) for factors associated with persistent use were estimated using a multivariable Poisson regression model. Hazard ratios (HRs) for all-cause mortality associated with persistent opioid use were estimated using multivariable Cox regression models. RESULTS: Of 14 347 eligible individuals (mean [SD] age = 61.9 [12.5]), 2285 (15.9%) developed persistent opioid use, with an incident rate of 25.5 per 1000 person-years. Risk factors included older age (≥65 vs < 65 years: RR = 1.63, 95% CI = 1.24 to 2.14), smoking (current: 1.89, 1.68 to 2.13; former: 1.30, 1.20 to 1.41), baseline comorbidities (Elixhauser Comorbidity Index 5+ vs 0: 1.70, 1.29 to 2.24), and substance use disorders (1.58, 1.43 to 1.74). All-cause mortality was doubled among individuals with persistent use (51.6, 48.0 to 55.6 per 1000 person-years) than in those without (25.3, 24.2 to 26.4). Persistent use was associated with an increased all-cause mortality (adjusted HR = 1.84, 1.66 to 2.04). CONCLUSIONS: Persistent opioid use was common in breast cancer survivors and associated with increased mortality. Further research is needed to explore factors that may be contributing to increased mortality.