Simple Blood Ratio Linked to Short-Term Death Risk After Heart Attack

A routinely measured blood value may help doctors gauge how likely patients are to die in the weeks after a heart attack. In a study drawing on the MIMIC-IV intensive care database, researchers report that the hemoglobin-to-red cell distribution width ratio, or HRR, was independently associated with both in-hospital and 90-day all-cause mortality among critically ill patients with acute myocardial infarction. Because both components come from a standard complete blood count, the ratio costs essentially nothing extra to calculate.

The analysis included 4,213 patients with acute myocardial infarction, with a median age of 72.35 years, and 63.11% were male. Each patient was assigned to one of three groups based on HRR levels: a lowest tertile with ratios of 0.66 or below, a middle tertile between 0.66 and 0.85, and a highest tertile at 0.85 or above. The outcomes examined were death from any cause during the hospital stay and within 90 days.

Patients in the higher HRR tertiles showed significantly lower mortality than those in the lowest tertile. After multivariable adjustment, higher continuous HRR was independently associated with reduced in-hospital mortality, with an adjusted hazard ratio of 0.46 (95% confidence interval 0.24 to 0.86, P = 0.016). The association with 90-day mortality was stronger still: the adjusted hazard ratio was 0.19 (95% confidence interval 0.12 to 0.31, P < 0.001).

Beyond the average association, the researchers probed the shape of the relationship using restricted cubic spline analysis. This revealed a non-linear association between HRR and 90-day mortality risk: risk decreased continuously as HRR rose above a Youden-derived cutoff of 0.74, with no plateau observed across the observed range. Kaplan-Meier survival curves reinforced the pattern, showing significantly better survival for patients in higher HRR tertiles, with a log-rank P value below 0.001.

Subgroup analyses were conducted to test whether the finding held across different patient characteristics. The association of elevated HRR with lower mortality remained consistent across the subgroups examined, although a significant interaction was observed for sepsis, suggesting the strength of the relationship may differ depending on whether patients also had that condition.

The authors conclude that HRR is an independent prognostic marker in acute myocardial infarction and that lower HRR levels may be associated with increased short-term mortality. They position the ratio as a readily available and cost-effective biomarker derived from routine laboratory testing that may serve as a valuable tool for early risk stratification in these patients.

Important caveats apply. The study is an observational analysis of a single intensive care database, so it demonstrates association rather than a causal protective effect of high HRR, and the population consists of critically ill patients whose generalizability to all heart attack presentations is uncertain. The reported hazard ratios come from statistical models whose adjustments determine how much confounding is removed, and the Youden-derived cutoff of 0.74 is an optimal threshold fitted to this dataset rather than a universally established clinical value. Within those limits, the findings add a nearly free laboratory measure to the growing list of routine blood markers under study for prognostic stratification after acute myocardial infarction.

Subject of Research: The association between the hemoglobin-to-red cell distribution width ratio and short-term mortality in critically ill patients with acute myocardial infarction

Article Title: The hemoglobin–to–red cell distribution width ratio to predict all–cause mortality in patients with acute myocardial infarction in the MIMIC–IV database

Article References: Zhang, Y., Zhou, N., Zheng, H., Tang, Y., Xu, H., Ai, X., Li, H., Xia, Y., & Cai, Y. (2026). The hemoglobin–to–red cell distribution width ratio to predict all–cause mortality in patients with acute myocardial infarction in the MIMIC–IV database. BMC Cardiovascular Disorders. https://doi.org/10.1186/s12872-026-06873-8

Image Credits: AI Generated

DOI: 10.1186/s12872-026-06873-8

Keywords: hemoglobin-to-red cell distribution width ratio, acute myocardial infarction, all-cause mortality, MIMIC-IV database, risk stratification, biomarker, red cell distribution width, hemoglobin, intensive care, prognosis, observational study, Kaplan-Meier analysis