Among 626 Vietnamese patients followed prospectively for three years after percutaneous coronary intervention (PCI), each unit increase in the hemoglobin-to-red cell distribution width ratio (HRR) was associated with a 24% lower risk of major adverse cardiovascular events (MACE) in unadjusted models (HR = 0.756; 95% CI 0.703–0.814), with the protective signal persisting after adjustment for age, sex, and comorbidities (HR = 0.810). MACE incidence fell progressively across ascending HRR quartiles, and HRR outperformed both its individual components and standard leukocyte- and platelet-derived inflammation indices in discriminative analysis.
HRR is an elegant composite: hemoglobin captures oxygen-carrying capacity and nutritional status, while red cell distribution width (RDW) reflects erythrocyte heterogeneity — a surrogate for systemic inflammation, oxidative stress, and dyserythropoiesis. Combining them amplifies prognostic signal beyond either alone, which aligns with mounting evidence that multi-dimensional blood indices outperform single biomarkers in cardiovascular risk stratification. The practical appeal is real: HRR requires no additional testing beyond a standard complete blood count, making it actionable in low-resource primary care settings where expensive biomarkers are impractical.
Limitations matter here. The single-country, multicenter design may limit generalizability to other ethnic and healthcare contexts. The cohort size of 626, while adequate for Cox modeling, is modest. Crucially, this is a preprint posted on medRxiv and has not yet undergone peer review — findings and effect sizes may shift substantially before publication. Consider this hypothesis-generating, not practice-changing, until validated in larger, ethnically diverse populations.
