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 under-investigated 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 non-metastatic breast cancer between 2009-2019 who filled two or more opioid prescriptions. Rates of persistent opioid use were estimated from first-year survivorship through December 31, 2021. Rate ratios (RR) and 95% confidence intervals (CI) for factors associated with persistent use were estimated using a multivariable Poisson regression model. Hazard ratios (HR) 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]), 2,285 (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, 1.24-2.14]), smoking (current: 1.89 [1.68- 2.13]; former: 1.30 [1.20-1.41]), baseline comorbidities (Elixhauser Comorbidity Index 5+ vs 0: 1.70 [1.29- 2.24]) and substance use disorders (1.58 [1.43- 1.74]). All-cause mortality was doubled among individuals with persistent use (51.6 [48.0-55.6] per 1000 person-years) than in those without (25.3 [24.2-26.4]). Persistent use was associated with an increased all-cause mortality (aHR:1.84 [1.66-2.04]).

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.