Hemoglobin as a Treatable Trait in COPD: A Retrospective Observational Cohort Study on Hemoglobin Levels and All-Cause Mortality from NHANES Data

This study identifies a nonlinear relationship between HGB levels and mortality in COPD, establishing 14.2 g/dL as a critical threshold that supports anemia's inclusion in the COPD "treatable traits" framework. Below this value, increasing HGB is associated with reduced mortality, whereas above it no further benefit is observed. Clinicians should prioritize HGB monitoring in high-risk subgroups (elderly males, smokers, and cardiac comorbidities).