Objective: To examine real-world adherence to oral anticancer agents (OAAs) and its association with outcomes among Medicare beneficiaries with metastatic renal cell carcinoma (mRCC).
Methods: SEER-Medicare retrospective cohort study of patients with metastatic renal cell carcinoma (mRCC) who received an OAA between 2007 and 2015. We examined A) adherence and B) overall and disease-specific 2-year survival landmarked at 3 months after OAA initiation. Adherence was assessed by calculating the proportion of days covered (PDC) within 3 months of OAA initiation, with adherent use being defined as PDC > 80%.
Results: A total of 905 patients met study criteria, of whom 445 patients (49.2%) were categorized as adherent to initial OAA treatment. Adjusting for clinical and demographic factors revealed decreased odds of adherence associated with living within an impoverished neighborhood (OR 0.49, CI 0.0.33 - 0.74) and out-of-pocket costs > $200 (OR 0.68, CI 0.47-.98). Adherence was associated with improved 2-year survival in univariate analysis (logrank test, P = .01) and a non-significant trend toward an association with decreased all-cause (HR 0.87, CI 0.72 - 1.05) and RCC-specific survival (HR 0.84, CI 0.69 - 1.03) in multivariable analysis.
Conclusion: Local poverty levels and high out-of-pocket costs are associated with poor initial adherence to OAA therapy in Medicare beneficiaries with mRCC, which in turn, suggests a trend toward poor overall and disease-specific survival. Efforts to improve outcomes in the broader mRCC population should incorporate OAA adherence and economic factors.
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