Evaluating the derivation of clinical adjusters in the EOM: Claims data vs practice-reported sources.

87 Background: The Enhancing Oncology Model (EOM) incorporates various cancer-specific clinical adjusters to establish cost benchmarks for different cancer types. For breast cancer, both HER2 status and metastatic status are used to define four distinct cost groups. However, reporting these statuses requires considerable operational effort, especially when physicians do not consistently document them in structured data fields or when these statuses change over time. Methods: We collaborated with a large community oncology practice representing nearly 10% of all EOM episodes. Using episode-level performance data, medical claims, and Part D drug event data from the first performance period, we identified HER2 status based on the presence of an outpatient HER2 drug claim, carrier claim, or Part D drug event. We then compared episode performance distributions based on the reported adjusters versus those derived from medical claims and Part D drug events. Results: A claims-based approach to HER2 status designation leads to a more accurate episode benchmark calculation, particularly because trastuzumab-deruxtecan—an HER2-directed therapy—can be used in HER2-low cases, which EOM categorizes as HER2-negative. Conclusions: Reporting HER2 status presents operational challenges, but deriving it from claims-based logic appears to be less burdensome while providing a reliable approach. However, a limitation of this approach is that it may fail to capture episodes in which HER2-positive patients do not receive HER2-targeted therapies. This risk needs to be balanced against data missingness and the application of HER2 status outside the price prediction model, which does not adequately account for evolving cost trends. Data type Period HER status identification method Average episode cost for HER2 positive episodes Average episode cost for not HER2 positive episodes Ratio Performance period 1 h2-2023 Claims based $46,882 $46,290 1.01 Performance period 1 h2-2023 Reported adjusters $43,943 $47,521 0.92