Inside Insights

HEOR models are only as credible as the inputs behind them. In rare diseases, those inputs are frequently incomplete: natural history is poorly characterized, endpoints are inconsistent, and small, fragmented patient populations amplify uncertainty in both clinical and economic parameters (Grand et
al., 2024; Pearson et al., 2018).

Real-world evidence (RWE) underpins modern health economics and outcomes research (HEOR), especially when traditional clinical trials are infeasible in rare diseases. Small patient populations, varying symptoms, and uncertain etiology can limit trial insight and complicate endpoint selection.