Red cell distribution width as an independent predictor of exercise intolerance and ventilatory inefficiency in patients with chronic heart failure

In-hospital changes in the red blood cell distribution width and mortality in critically ill patients with heart failure

AIMS

A high red blood cell distribution width (RDW) at admission or discharge is associated with a worse prognosis in hospitalized patients with heart failure (HF), and the prognostic value of the in-hospital change in RDW (∆RDW) remains debatable.

METHODS AND RESULTS

We included 5514 patients with critical illness and HF from the MIMIC-IV database. The ΔRDW was calculated by the RDW at discharge minus that at admission. Clinical outcomes included all-cause mortality at 90 day, 180 day, and 1 year after discharge. The median age of the patients was 73.91 years, and 46.37% were women. Kaplan-Meier curve and Cox regression analyses were used to examine the association between the ΔRDW and all-cause mortality at different time points. A multivariable Cox proportional hazard model showed that the ΔRDW (per 1% increase) was independently associated with all-cause mortality at 90 day, 180 day, and 1 year after adjusting for confounding factors (hazard ratio [HR] = 1.17, 95% confidence interval [CI] = 1.13-1.21, P < 0.001; HR = 1.17, 95% CI = 1.14-1.20, P < 0.001; and HR = 1.18, 95% CI = 1.15-1.20, P < 0.001, respectively). Restricted cubic splines showed a non-linear relationship between the ΔRDW and the risk of clinical outcomes. High ΔRDW was associated with a high risk of mortality at different time points. A subgroup analysis showed that this positive association remained consistent in pre-specified subgroups.

CONCLUSIONS

Our study suggests that an increased RDW during hospitalization is independently associated with short- or long-term all-cause mortality in critical-ill patients with HF.

[Red cell distribution width as a predictor of impaired exercise capacity in patients with heart failure]

Aim    To test a hypothesis that increased values of red cell distribution width (RDW) in patients with chronic heart failure (CHF) can be related with low exercise tolerance.Material and methods    102 patients were evaluated who had CHF with mid-range and reduced left ventricular ejection fraction (LV EF) without anemia (72% men, mean age 66±10.2 years). Cardiopulmonary stress test (CPST), echocardiography, 6‑min walk test (6MWT), blood count, and measurements of N-terminal pro-brain natriuretic peptide (NT-pro-BNP) and serum iron were performed.Results    The average LV EF was 39±8.7 %; the peak oxygen consumption (VO2peak) was 13.7±4.8 ml /kg /min; and the median NT-pro-BNP was 595.3 pg /ml (Q1-3 1443-2401). RDW variables, including the RDW coefficient of variation (RDW-CV) and RDW standard deviation (RDW-SD), were not significantly related with serum iron or hemoglobin concentrations. A one-factor linear regression analysis showed a significant correlation of VO2peak with RDW-SD (р=0.039). A multivariate linear regression analysis with adjustments for LV EF, hemoglobin concentration, and age did not reveal any significant correlation of VO2peak with RDW variables. The distance covered in the 6MWT was significantly associated with RDW-CV both in the one-factor analysis and with adjustments for LV EF, hemoglobin and serum iron concentrations, and age.Conclusion    This study showed that high RDW values in CHF patients without anemia predicted low exercise tolerance regardless of the age, LV systolic function, and hemoglobin and serum iron concentrations. A 16% increase in RDW-CV significantly decreased the likelihood of covering a distance longer than 360 m during 6 min.

Red Blood Cell Distribution Width in Heart Failure: Pathophysiology, Prognostic Role, Controversies and Dilemmas

Red blood cell distribution width (RDW), an integral parameter of the complete blood count (CBC), has been traditionally used for the classification of several types of anemia. However, over the last decade RDW has been associated with outcome in patients with several cardiovascular diseases including heart failure. The role of RDW in acute, chronic and advanced heart failure is the focus of the present work. Several pathophysiological mechanisms of RDW’s increase in heart failure have been proposed (i.e., inflammation, oxidative stress, adrenergic stimulation, undernutrition, ineffective erythropoiesis, reduced iron mobilization, etc.); however, the exact mechanism remains unknown. Although high RDW values at admission and discharge have been associated with adverse prognosis in hospitalized heart failure patients, the prognostic role of in-hospital RDW changes (ΔRDW) remains debatable. RDW has been incorporated in recent heart failure prognostic models. Utilizing RDW as a treatment target in heart failure may be a promising area of research.

Association between the Red Cell Distribution Width and Vasospastic Angina in Korean Patients

PURPOSE

The association between the red cell distribution width (RDW) and vasospastic angina (VSA) has not been elucidated. We investigated the association of the RDW with the incidence and angiographic subtypes of VSA in Korean patients.

MATERIALS AND METHODS

A total of 460 patients who underwent intracoronary ergonovine provocation tests were consecutively enrolled and classified into two groups: the VSA group (n=147, 32.0%) and non-VSA group (n=313, 68.0%). The subjects were classified into 3 subgroups (tertiles) according to the baseline level of RDW assessed before the angiographic provocation test.

RESULTS

The VSA group had a higher RDW than the non-VSA group (12.9±0.8% vs. 12.5±0.7%, p=0.013). The high RDW level demonstrated an independent association with the high incidence of VSA [second tertile: hazard ratio (HR) 1.96 (1.13-2.83), third tertile: HR 2.33 (1.22-3.47), all p<0.001]. Moreover, the highest RDW tertile level had a significant association with the prevalence of the mixed-type coronary spasm [HR 1.29 (1.03-1.59), p=0.037].

CONCLUSION

The high level of RDW was significantly associated with the prevalence of VSA and the high-risk angiographic subtype of coronary spasm, suggesting that a proactive clinical investigation for VSA could be valuable in Korean patients with an elevated RDW.