Red cell distribution width and mortality in predominantly African-American population with decompensated heart failure

Red blood cell distribution width and all-cause mortality in congestive heart failure patients: a retrospective cohort study based on the Mimic-III database

Background

The red blood cell distribution width (RDW) is a metric that measures the variation in the size of red blood cells and is presented as the red blood cell volume coefficient of variation. Increased RDW levels are closely linked to an elevated risk of death from congestive heart failure (CHF) and might be a new risk marker for cardiovascular disease. This research sought to evaluate the possible link between RDW levels and all-cause mortality in CHF patients after controlling for other covariates.

Methods

The publicly accessible Mimic-III database served as the source of data for our research. We employed ICU admission scoring systems to gather information on each patient's demographical data, laboratory test results, comorbid conditions, vital signs, and scores. Among CHF patients, the link between baseline RDW levels and short-, medium-, and long-term all-cause mortality was evaluated by Cox proportional hazard analysis, smooth curve fitting, and Kaplan-Meier survival curves.

Results

In total, 4,955 participants were selected for the study with an average age of 72.3 ± 13.5 years (old) and with males accounting for 53.1%. The findings recorded from the fully adjusted Cox proportional hazard model showed that higher RDW was associated with a greater risk of 30-day, 90-day, 365-day, and 4-year all-cause death; the HRs and 95% confidence intervals were 1.11 (1.05, 1.16), 1.09 (1.04, 1.13), 1.10 (1.06, 1.14), and 1.10 (1.06, 1.13), respectively. The results were stable and reliable using subgroup analysis. Smooth curve fitting and the K-M survival curve method further validated our results.

Conclusion

The RDW levels had a u-shaped connection with 30-day mortality. The RDW level was linked to an elevated risk of short-, medium-, and long-term all-cause death among CHF patients.

The Relation Between Red Blood Cell Distribution Width and Coronary Atherosclerotic Plaque Vulnerability Detected by Intracoronary Optical Coherence Tomography

BACKGROUND

A higher red blood cell distribution width (RDW) predicts major adverse cardiac events in patients with coronary artery disease (CAD). However, there are only a few studies regarding the relationship between RDW and vulnerable plaques. Thus, the purpose of the present study is to retrospectively explore the predictive value of the association between RDW and plaque vulnerability assessed by optical coherence tomography (OCT) in patients with cardiovascular (CV) diseases.

METHODS

This study included 35 patients with stable angina pectoris (SAP) and 70 patients with the acute coronary syndrome (ACS). We documented clinical features as well as peripheral RDW. Plaque vulnerability was determined by OCT. We defined thin-cap fibroatheroma (TCFA) as a lipid-rich plaque (fibrous cap <65 μm thick).

RESULTS

Plaque rupture was detected more frequently in patients with ACS compared with patients with SAP (62.9 vs. 2.9%, p<0.001, and the corresponding TCFA were 50.69±15.68 vs. 80.03±21.60 μm, p<0.001, respectively). A higher RDW was found in patients with ACS than in patients with SAP (p<0.001). A cut-off value of RDW >13.85% could detect ruptured plaque with a sensitivity of 72.3% and a specificity of 62%.

CONCLUSION

TCFA and plaque rupture were detected more frequently in patients with ACS compared with SAP. Elevated RDW was positively the predictive value of the association between plaque vulnerability.

Red cell distribution width is associated with short-term mortality in critically ill patients with heart failure

AIMS

There is limited evidence for the correlation between short-term mortality and red cell distribution width (RDW) in critical patients with heart failure. Herein, a retrospective cohort study was conducted to investigate whether RDW was independently associated with short-term mortality in critically ill patients with heart failure.

METHODS AND RESULTS

As a retrospective cohort study, it involved a total of 9465 patients with heart failure from the MIMIC-IV database. The target-dependent and independent variables were in-hospital mortality, 90 day mortality and RDW measured at baseline, respectively. The relationship between all-cause death and baseline RDW in hospital and after 90 days of admission to ICU was evaluated by using the Kaplan-Meier plot and Cox proportional hazard analysis. The average age of participants was 74.4 (64.2, 83.5) years old, among whom about 54.6% were male. Results of the adjusted Cox proportional hazard model revealed that RDW had a positive association with both in-hospital and 90 day mortality risk after the adjustment of confounders (HR = 1.09, 95% CI: 1.04-1.15, P < 0.001; HR = 1.11, 95% CI: 1.08-1.14, P < 0.001, respectively). A non-linear relationship was found between RDW and 90 day mortality, which had a threshold of 14.96%. The effect sizes and confidence intervals below and above the threshold were 1.36 (1.14 to 1.62) and 1.09 (1.04 to 1.15), respectively. It was also found by subgroup analysis that there were stronger correlations in male and patients with normal renal function.

CONCLUSIONS

Our data suggest that the short-term mortality of critically ill patients with HF is independently predicted by RDW. At the same time, large prospective research and longer follow-up time are required to further validate the findings of this study.

Cardiovascular Risk Assessment Using Artificial Intelligence-Enabled Event Adjudication and Hematologic Predictors

BACKGROUND

Researchers routinely evaluate novel biomarkers for incorporation into clinical risk models, weighing tradeoffs between cost, availability, and ease of deployment. For risk assessment in population health initiatives, ideal inputs would be those already available for most patients. We hypothesized that common hematologic markers (eg, hematocrit), available in an outpatient complete blood count without differential, would be useful to develop risk models for cardiovascular events.

METHODS

We developed Cox proportional hazards models for predicting heart attack, ischemic stroke, heart failure hospitalization, revascularization, and all-cause mortality. For predictors, we used 10 hematologic indices (eg, hematocrit) from routine laboratory measurements, collected March 2016 to May 2017 along with demographic data and diagnostic codes. As outcomes, we used neural network-based automated event adjudication of 1 028 294 discharge summaries. We trained models on 23 238 patients from one hospital in Boston and evaluated them on 29 671 patients from a second one. We assessed calibration using Brier score and discrimination using Harrell's concordance index. In addition, to determine the utility of high-dimensional interactions, we compared our proportional hazards models to random survival forest models.

RESULTS

Event rates in our cohort ranged from 0.0067 to 0.075 per person-year. Models using only hematology indices had concordance index ranging from 0.60 to 0.80 on an external validation set and showed the best discrimination when predicting heart failure (0.80 [95% CI, 0.79-0.82]) and all-cause mortality (0.78 [0.77-0.80]). Compared with models trained only on demographic data and diagnostic codes, models that also used hematology indices had better discrimination and calibration. The concordance index of the resulting models ranged from 0.75 to 0.85 and the improvement in concordance index ranged up to 0.072. Random survival forests had minimal improvement over proportional hazards models.

CONCLUSIONS

We conclude that low-cost, ubiquitous inputs, if biologically informative, can provide population-level readouts of risk.

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.

The prognostic value of interaction between mean corpuscular volume and red cell distribution width in mortality in chronic kidney disease

Recently, both red cell distribution width (RDW) and mean corpuscular volume (MCV) have been associated with unfavorable outcomes in several medical conditions. Therefore, we conducted this retrospective study of 1075 patients with stage 3-5 chronic kidney disease to investigate whether interactions between RDW and MCV influence the risk of mortality. These patients were divided into four groups: group A (n = 415), RDW ≤ 14.9% and MCV ≤ 91.6 fL; group B (n = 232), RDW > 14.9% and MCV ≤ 91.6 fL; group C (n = 307), RDW ≤ 14.9% and MCV > 91.6 fL; and group D (n = 121), RDW > 14.9% and MCV > 91.6 fL. The adjusted hazard ratio (HR) of all-cause mortality for group B versus group A was 1.44 (95% confidence interval [CI], 1.14-2.12, p = 0.02), group C versus group A 2.14 (95% CI, 1.31-3.48, p = 0.002), and group D versus group A 5.06 (95% CI, 3.06-8.37, p < 0.001). There was a multiplicative interaction between MCV and RDW in predicting patient mortality. The use of RDW in conjunction with MCV may improve healthcare by identifying those at an increased risk for mortality compared with the use of either RDW or MCV alone.

An overall and dose-response meta-analysis of red blood cell distribution width and CVD outcomes

Red blood cell distribution width (RDW) is the coefficient of variation of red blood cell size, considered to be associated with cardiovascular disease (CVD). This study aimed to comprehensively synthesize previous studies on RDW and CVD outcomes through an overall and dose-response meta-analysis. PubMed, Embase and Web of Science were searched systematically for English and Chinese language publications up to November 30, 2015. We extracted data from publications matching our inclusion criteria for calculating pooled hazard ratio (HR), which was used to assess prognostic impact of RDW on CVD. Twenty-seven articles, consisting of 28 studies and 102,689 participants (mean age 63.9 years, 63,703 males/36,846 females, 2,140 gender-unmentioned subjects) were included in the present meta-analysis. The pooled HRs are 1.12 (95% CI = 1.09-1.15) for the association of all-cause mortality (ACM) per 1% increase of RDW, 1.12(95% CI = 1.08-1.17) for major adverse cardiac events (MACEs) per 1% increase of RDW. A dose-response curve relating RDW increase to its effect on CVD outcomes was established (p_curve < 0.001). For every 1-unit increase of RDW, there is an increased risk of occurrence of ACM (pooled HR = 1.03, 95% CI = 1.02-1.04) and MACEs (pooled HR = 1.04, 95% CI = 1.01-1.06). This study indicates RDW may be a prognostic indicator for CVD outcomes.

Supraventricular tachycardia during the first year of life: is subclinical inflammation the trigger?

BACKGROUND

Neutrophil/lymphocyte ratio (NLR) and red cell distribution width (RDW) may be associated with the onset of arrhythmias in adults, thus underlining a possible inflammatory etiology. Paroxysmal supraventricular tachycardia (SVT) is the most frequent pathological tachycardia in childhood.

AIM

To verify NLR and RDW levels in a group of children (<1 year) affected by SVT with a structurally normal heart and without fever or inflammatory diseases; to compare NLR and RDW before and after SVT resolution, to verify whether the latter was related with the reduction in inflammatory state; to identify - in SVT subtypes caused by a reentry mechanism - an NLR and RDW cutoff point beyond which adenosine was ineffective in preventing SVT recurrence.

METHODS

Eighteen SVT patients were recruited (mean age 18.9 ± 3.2 days; 50% males) and compared with 18 healthy peers.

RESULTS

NLR was higher in SVT group than in controls (p < 0.03). A significant difference was revealed between NLR values obtained on admission and at discharge (p < 0.05). On the contrary, no significant differences were found for RDW. It was not possible to identify NLR or RDW cutoffs capable of predicting SVT recurrence. However, all patients featuring SVT recurrence following adenosine injection presented with a lymphocyte count >6000/mm³.

CONCLUSIONS

Elevated NLR is associated with an increased risk of SVT during the first year of life, while its decline looks like to lead the SVT resolution. A subclinical inflammatory status, as assessed by lymphocytes count, influences SVT recurrence. These results provide further support for an inflammatory etiology of SVT in babies.

Red Cell Distribution Width and Severe Left Ventricular Dysfunction in Ischemic Heart Failure

OBJECTIVE

The red cell distribution width (RDW), a simple and widely available marker, has been linked with an increased risk of adverse outcomes in patients with heart failure (HF) and risk of death, and cardiovascular events in those with previous myocardial infarction, but its relation with the severity of left ventricular (LV) dysfunction is not fully investigated. The aim of this study was to assess the prognostic value of the RDW in post myocardial infarction patients with typical signs and symptoms of HF and with reduced LV ejection fraction (EF).

METHODS

Patients (n = 350) came from an ongoing registry of consecutive patients who admitted for ischemic heart disease at our center. All patients were followed up 1 year after the initial hospitalization by telephone interviews. The outcomes studied were mortality and hospitalization because of decompensated HF.

RESULTS

RDW-coefficient of variation (express in percentage) was calculated from SD of mean corpuscular volume and mean corpuscular volume itself. Using logistic regression analysis, 3 variables consisting age, RDW level, and hemoglobin were identified as independent predictors of severe LV dysfunction (LVEF <30%). Levels of RDW were associated with the presence of severe LV dysfunction, with an accuracy of 61.4% (95% confidence interval: 56.2%-66.4%) and 66.9% (95% confidence interval: 61.8%-71.6%), using cut-off values of higher than 13.5 and 13.8, respectively.

CONCLUSION

Our results suggest that elevated RDW may be used as a prognostic tool among HF patients with the documented myocardial infarction because it is an inexpensive, rapidly calculated test that is already routinely in use in practice.

Exome Genotyping Identifies Pleiotropic Variants Associated with Red Blood Cell Traits

Red blood cell (RBC) traits are important heritable clinical biomarkers and modifiers of disease severity. To identify coding genetic variants associated with these traits, we conducted meta-analyses of seven RBC phenotypes in 130,273 multi-ethnic individuals from studies genotyped on an exome array. After conditional analyses and replication in 27,480 independent individuals, we identified 16 new RBC variants. We found low-frequency missense variants in MAP1A (rs55707100, minor allele frequency [MAF] = 3.3%, p = 2 × 10(-10) for hemoglobin [HGB]) and HNF4A (rs1800961, MAF = 2.4%, p < 3 × 10(-8) for hematocrit [HCT] and HGB). In African Americans, we identified a nonsense variant in CD36 associated with higher RBC distribution width (rs3211938, MAF = 8.7%, p = 7 × 10(-11)) and showed that it is associated with lower CD36 expression and strong allelic imbalance in ex vivo differentiated human erythroblasts. We also identified a rare missense variant in ALAS2 (rs201062903, MAF = 0.2%) associated with lower mean corpuscular volume and mean corpuscular hemoglobin (p < 8 × 10(-9)). Mendelian mutations in ALAS2 are a cause of sideroblastic anemia and erythropoietic protoporphyria. Gene-based testing highlighted three rare missense variants in PKLR, a gene mutated in Mendelian non-spherocytic hemolytic anemia, associated with HGB and HCT (SKAT p < 8 × 10(-7)). These rare, low-frequency, and common RBC variants showed pleiotropy, being also associated with platelet, white blood cell, and lipid traits. Our association results and functional annotation suggest the involvement of new genes in human erythropoiesis. We also confirm that rare and low-frequency variants play a role in the architecture of complex human traits, although their phenotypic effect is generally smaller than originally anticipated.

Red cell distribution width and mortality in acute heart failure patients with preserved and reduced ejection fraction

Background

Elevated red blood cell distribution width (RDW) is a valid predictor of outcome in acute heart failure (AHF). It is unknown whether elevated RDW remains predictive in AHF patients with either preserved left ventricular ejection fraction (LVEF) ≥50% or reduced LVEF (<50%).

Methods and results

Prospective local registry including 402 consecutive hospitalized AHF patients without acute coronary syndrome or need of intensive care. The primary outcome was all‐cause mortality (ACM) at 1 year after admission. Demographic and clinical data derive from admission, echocardiographic examinations (n = 269; 67%) from hospitalization.

The Cox proportional hazard model including all patients (P < 0.001) was adjusted for age, gender, and RDW quartiles. Independent predictors of 1‐year ACM were cardiogenic shock (HR 2.86; CI: 1.3–6.4), male sex (HR 1.9; CI: 1.2–2.9), high RDW quartile (HR 1.66; CI: 1.02–2.8), chronic HF (HR 1.61; CI: 1.05–2.5), valvular heart disease (HR 1.61; CI: 1.09–2.4), increased diastolic blood pressure (HR 1.02 per mmHg; CI: 1.01–1.03), increasing age (HR 1.04 by year; CI: 1.02–1.07), platelet count (HR 1.002 per G/l; CI: 1.0–1.004), systolic blood pressure (HR 0.99 per mmHg; CI: 0.98–0.99), and weight (HR 0.98 per kg; CI: 0.97–0.99). A total of 114 patients (28.4%) died within the first year; ACM of all patients increased with quartiles of rising RDW (χ² 18; P < 0.001). ACM was not different between RDW quartiles of patients with reduced LVEF (n = 153; χ² 6.6; P = 0.084). In AHF with LVEF ≥50% the probability of ACM increased with rising RDW (n = 116; χ² 9.9; P = 0.0195).

Conclusions

High RDW is associated with increased ACM in AHF patients with preserved but not with reduced LVEF in this study population.

Red cell distribution width (RDW) correlates with markers of diastolic dysfunction in patients with impaired left ventricular systolic function

Objective

Red-cell distribution width (RDW) has been identified as a novel prognostic marker in a heterogeneous group of heart failure patients. In this group, diastolic dysfunction is associated with worse outcome. As the evidence is limited, the aim of the present study was to assess the relationship of RDW to diastolic markers in patients with left ventricular dysfunction (LVD) diagnosed during cardiac catheterization.

Methods

Clinical and angiographic data were collected retrospectively on a total of 291 stable patients (mean age 62 years, 199 males) with systolic dysfunction documented during cardiac catheterization in a regional medical center between January 2006 and December 2010.

Results

Positive association was seen between RDW and Left ventricular end diastolic pressure (LVEDP), estimated systolic pulmonary arterial pressure(sPAP), and left atrial dimension (LAD) (r: 0.18, 0.24, 0.28, respectively; p:<0.05).Three year retrospective survival analysis for 108 patients admitted in the first 2 years showed a statistically significant decrease in survival patients with high RDW(> 14.5) vs. normal RDW (73%vs.88%;log rank p:0.03). This was seen even in the asymptomatic subgroup (71% vs. 94%; log rank p: 0.01).

Conclusion

RDW correlates with markers of diastolic dysfunction in patients with LVD. Additionally, in patients asymptomatic LVD, high RDW is still associated with lower survival.

Red cell distribution width is associated with future risk of incident stroke. The Tromsø Study

Red cell distribution width (RDW), a measure of the variability in size of the circulating erythrocytes, is associated with cardiovascular morbidity and mortality. We aimed to investigate whether RDW was associated with incident stroke and case fatality in subjects recruited from the general population. Baseline characteristics were obtained from 25,992 subjects participating in the fourth survey of the Tromsø Study, conducted in 1994/95. Incident stroke was registered from inclusion until December 31, 2010. Cox regression models were used to calculate hazard ratios (HR) with 95% confidence intervals (95% CI) for stroke, adjusted for age, sex, body mass index, smoking, haemoglobin level, white blood cell count, thrombocyte count, hypertension, total cholesterol, triglycerides, self-reported diabetes, and red blood cell count. During a median follow-up of 15.8 years, 1152 participants experienced a first-ever stroke. A 1% increment in RDW yielded a 13% higher risk of stroke (multivariable HR: 1.13, 95% CI: 1.07-1.20). Subjects with RDW in the highest quintile compared to the lowest had a 37% higher risk of stroke in multivariable analysis (HR: 1.37, 95% CI: 1.11-1.69). Subjects with RDW above the 95-percentile had 55% higher risk of stroke compared to those in the lowest quintile (HR: 1.55, 95% CI: 1.16-2.06). All risk estimates remained unchanged after exclusion of subjects with anaemia (n=1102). RDW was not associated with increased risk of death within one year or during the entire follow-up after an incident stroke. RDW is associated with incident stroke in a general population, independent of anaemia and traditional atherosclerotic risk factors.

Red cell distribution width and carotid atherosclerosis progression. The Tromsø Study

Red cell distribution width (RDW), a measure of the size variability of circulating erythrocytes, is associated with cardiovascular morbidity and mortality. We aimed to investigate whether RDW was associated with progression of atherosclerotic plaques in subjects recruited from the general population. Baseline characteristics, including RDW, were collected from 4677 participants in the fourth survey of the Tromsø Study conducted in 1994/95. Prevalence of carotid plaques and total plaque area (TPA) were assessed by ultrasonographic imaging at baseline and after seven years of follow-up. Generalised linear models were used to analyse change in TPA across tertiles of RDW. Change in TPA was significantly higher across tertiles of RDW in crude analysis and in multivariable analysis adjusted for cardiovascular risk factors. The mean change in TPA increased from 5.6 mm² (4.9-6.4) in tertile 1 (RDW ≤ 12.6 %) to 6.7 mm² (5.9-7.6) in tertile 3 (RDW ≥ 13.3) in multivariable analysis adjusted for body mass index, total cholesterol, HDL cholesterol, systolic blood pressure, self-reported diabetes, smoking status, platelet count, white blood cell count, and hs-CRP levels (p for trend 0.003). A 1 % increase in RDW was associated with 0.6 mm² (0.1-1.2) increase in TPA in multivariable analysis (p=0.03). RDW was associated with progression of atherosclerosis after adjustments for traditional atherosclerotic risk factors. Our findings suggest that the link between RDW and cardiovascular morbidity and mortality may be explained by atherosclerosis.

Red cell distribution width in type 2 diabetic patients

OBJECTIVE

To study the indices of some elements of the complete blood count, in type 2 diabetic patients, in comparison with nondiabetic healthy controls; and to find out the effects of glycemic control and different medications on these indices. To the best of our knowledge, this study is novel in our environment and will serve as a foundation for other researchers in this field.

METHODS

This retrospective study included 260 type 2 diabetic patients on treatment and 44 healthy control subjects. Sex, age, weight, height, blood pressure, complete blood count, fasting plasma glucose, hemoglobin A1c (HbA1c), and lipid profile data, were available for all of the study population. For diabetic patients, data on duration of diabetes and all medications were also available.

RESULTS

Red cell distribution width (RDW) was significantly higher in diabetic patients than in control subjects (P=0.008). It was also higher in patients with uncontrolled glycemia (HbA1c >7%) than those with good control (HbA1c ≤7%; P=0.035). Mean platelet volume (MPV) was comparable in both diabetic patients and healthy controls (P=0.238). RDW and MPV did not significantly correlate with fasting plasma glucose, HbA1c, or duration of diabetes. Both aspirin and clopidogrel did not show a significant effect on MPV. Both insulin and oral hypoglycemic agents did not show a significant effect on RDW, mean corpuscular volume, MPV, platelet count, or white blood cell count. Diabetic patients treated with indapamide or the combined thiazides and angiotensin receptor blockers showed no significant difference in RDW when compared with the control subjects.

CONCLUSION

RDW, which is recently considered as an inflammatory marker with a significant predictive value of mortality in diseased and healthy populations, is significantly higher in diabetic patients than healthy subjects and is particularly higher in uncontrolled glycemia. None of the studied hypoglycemic agents showed a significant effect on RDW. Diabetic hypertensive patients receiving antihypertensive therapy in the form of indapamide or the combined therapy of thiazides and angiotensin receptor blockers have RDW values comparable to those of the healthy population.

Red blood cell distribution width: A simple parameter with multiple clinical applications

The red blood cell distribution width (RDW) is a simple and inexpensive parameter, which reflects the degree of heterogeneity of erythrocyte volume (conventionally known as anisocytosis), and is traditionally used in laboratory hematology for differential diagnosis of anemias. Nonetheless, recent evidence attests that anisocytosis is commonplace in human disorders such as cardiovascular disease, venous thromboembolism, cancer, diabetes, community-acquired pneumonia, chronic obstructive pulmonary disease, liver and kidney failure, as well as in other acute or chronic conditions. Despite some demographic and analytical issues related to the routine assessment that may impair its clinical usefulness, an increased RDW has a high negative predictive value for diagnosing a variety of disorders, but also conveys important information for short- and long-term prognosis. Even more importantly, the value of RDW is now being regarded as a strong and independent risk factor for death in the general population. Although it has not been definitely established whether an increased value of RDW is a risk factor or should only be considered an epiphenomenon of an underlying biological and metabolic imbalance, it seems reasonable to suggest that the assessment of this parameter should be broadened far beyond the differential diagnosis of anemias. An increased RDW mirrors a profound deregulation of erythrocyte homeostasis involving both impaired erythropoiesis and abnormal red blood cell survival, which may be attributed to a variety of underlying metabolic abnormalities such as shortening of telomere length, oxidative stress, inflammation, poor nutritional status, dyslipidemia, hypertension, erythrocyte fragmentation and alteration of erythropoietin function. As such, the aim of this article is to provide general information about RDW and its routine assessment, to review the most relevant implications in health and disease and give some insights about its potential clinical applications.

Prognostic value of red blood cell distribution width for patients with heart failure: a systematic review and meta-analysis of cohort studies

Aims

Multiple studies have investigated the prognostic role of red blood cell distribution width (RDW) for patients with heart failure (HF), but the results have been inconsistent. The aim of the present study was to estimate the impact of RDW on the prognosis of HF by performing a systematic review and meta-analysis.

Methods and Results

The Embase, PubMed, and Web of Science databases were searched up to November 16, 2013 to identify eligible cohort studies. The quality of each study was assessed using the Newcastle-Ottawa Scale (NOS). The association between RDW, either on admission or at discharge, and HF outcomes (all-cause mortality [ACM], heart transplantation, cardiovascular mortality, and rehospitalization, etc.) were reviewed. The overall hazard ratio (HR) for the effect of RDW on ACM was pooled using a random-effects model, and the publication bias was evaluated using funnel plots and Eggers' tests. Seventeen studies, with a total of 18288 HF patients, were included for systematic review. All eligible studies indicated that RDW on admission and RDW at discharge, as well as its change during treatment, were of prognostic significance for HF patients. The HR for the effect of a 1% increase in baseline RDW on ACM was 1.10 (95% confidence interval: 1.07–1.13), based on pooling of nine studies that provided related data. However, publication bias was observed among these studies.

Conclusions

HF patients with higher RDW may have poorer prognosis than those with lower RDW. Further studies are needed to explore the potential mechanisms underlying this association.

Multiplicative interaction between mean corpuscular volume and red cell distribution width in predicting mortality of elderly patients with and without anemia

Recent studies have shown that an elevated red cell distribution width (RDW) is an important predictor of adverse outcomes. However, the strength of this biomarker has not been tested in a large outpatient elderly population. Also since increased RDW can be due to a variety of etiologies, additional biomarkers are needed to refine the prognostic value of this variable. We assembled a cohort of 36,226 elderly (≥65yo) patients seen at an outpatient facility within the Einstein/Montefiore system from January 1st 1997 to May 1st 2008 who also had a complete blood count performed within 3 months of the initial visit. With a maximum follow-up of 10 years, we found that an elevated RDW (>16.6) was associated with increased risk of mortality in both non-anemic (HR = 3.66, p < 0.05) and anemic patients (HR = 1.87, p < 0.05). The effect of RDW on mortality is significantly increased in non-anemic patients with macrocytosis (HR = 5.22, p < 0.05) compared to those with normocytosis (HR = 3.86, p < 0.05) and microcytosis (HR = 2.46, p < 0.05). When comparing non-anemic patients with both an elevated RDW and macrocytosis to those with neither, we observed an elevated HR of 7.76 (higher than expected in an additive model). This multiplicative interaction was not observed in anemic patients (HR = 2.23). Lastly, we constructed Kaplan-Meier curves for each RDW/MCV subgroup and found worsened survival for those with macrocytosis and an elevated RDW in both anemia and non-anemic patients. Based on our results, the addition of MCV appears to improve the prognostic value of RDW as a predictor of overall survival in elderly patients.

Effect of atorvastatin on hematologic parameters in patients with hypercholesterolemia

Hematologic parameters such as mean platelet volume (MPV), red cell distribution width (RDW), and neutrophil to lymphocyte (N/L) ratio are associated with increased cardiovascular risk. We investigated the effect of atorvastatin on hematologic parameters in patients with hypercholesterolemia. A total of 79 patients with hypercholesterolemia and 47 normocholesterolemic healthy participants were included. Patients with hypercholesterolemia received 10 to 80 mg/d atorvastatin during a 24-week period. Hematologic parameters were measured at baseline and after 6 months. Atorvastatin treatment produced a significant decrease in MPV levels (9.3 ± 1.3 vs 9.1 ± 1.2 fL, P = .008) and platelet count (259 ± 61 vs 248 ± 51 10(9)/L, P = .005). The N/L ratio decreased significantly after atorvastatin treatment from 2.9 ± 1.2 to 2.6 ± 1.1, (P = .014). The RDW and platelet distribution width levels were not different among the study groups, before and after treatment. Atorvastatin may beneficially reduce MPV levels and N/L ratio. This antiplatelet and anti-inflammatory effect of atorvastatin treatment could play a role in reducing cardiovascular risk.

Association of the red cell distribution width with red blood cell deformability

The red cell distribution width (RDW) is a component of the automated complete blood count (CBC) that quantifies heterogeneity in the size of circulating erythrocytes. Higher RDW values reflect greater variation in red blood cell (RBC) volumes and are associated with increased risk for cardiovascular disease (CVD) events. The mechanisms underlying this association are unclear, but RBC deformability might play a role. CBCs were assessed in 293 adults who were clinically examined. RBC deformability (expressed as the elongation index) was measured using a microfluidic slit-flow ektacytometer. Multivariate regression analysis identified a clear threshold effect whereby RDW values above 14.0% were significantly associated with decreased RBC deformability (β = -0.24; p = 0.003). This association was stronger after excluding anemic participants (β = -0.40; p = 0.008). Greater variation in RBC volumes (increased RDW) is associated with decreased RBC deformability, which can impair blood flow through the microcirculation. The resultant hypoxia may help to explain the previously reported increased risk for CVD events associated with elevated RDW.

Red cell distribution width, inflammatory markers and cardiorespiratory fitness: results from the National Health and Nutrition Examination Survey

AIMS

Cardiorespiratory fitness is an important predictor of cardiovascular morbidity and mortality. Both red cell distribution width (RDW) and inflammatory markers like C-reactive protein (CRP) have been shown to predict adverse outcomes in patients with heart disease.

METHODS

We utilized pooled data from NHANES 1999-2004 to assess cardiorespiratory fitness in healthy adults 12-49 years old using submaximal exercise. The primary outcome was the estimated maximal oxygen uptake (VO2max). Low fitness was defined as VO2max < 20th percentile of age- and gender-based reference category.

RESULTS

In our study, we estimated 21.2% of individuals had low fitness. Elevated RDW (>13%) was encountered in 20.4% subjects with low fitness as compared to 14.0% subjects in the control group (p < 0.001). Similarly, elevated CRP (>0.5 mg/dL) was found among 17.4% subjects with low fitness as compared to 12.4% subjects in the control group (p < 0.001). Adjusted analysis demonstrated a dose-response relationship between low cardiorespiratory fitness and increasing RDW or CRP.

CONCLUSION

In a large representative database of general US population, we observed a significant association between elevated RDW and elevated CRP with low cardiorespiratory fitness.

Gender and ethnic differences in red cell distribution width and its association with mortality among low risk healthy United state adults

Limited information is available about gender and ethnic differences in red cell distribution width (RCDW) with regard to its relation to mortality in a population free of cardiovascular (CV) disease and diabetes. To assess gender and ethnic differences in RCDW and their effect on the association between RCDW and mortality, the Third National Health and Nutritional Examination Survey (n = 15,460, 1988 to 1994) data were examined. Multivariate adjusted Cox proportional hazard analysis was performed to assess effect of gender and ethnicity on the association between RCDW and mortality (total, CV disease, and coronary heart disease [CHD]). RCDW (mean ± SE) was greater in black women (13.1 ± 0.03) and men (13.4 ± 0.02) compared to women of white (12.9 ± 0.02) and other (13.0 ± 0.07) ethnicities and men of white (13.3 ± 0.02) and other (13.3 ± 0.07) ethnicities, respectively (p <0.001). The interaction between RCDW and gender was statistically significant for all study outcomes (p <0.001) but nonsignificant for RCDW and ethnicity. After adjusting for key variables, RCDW in women was associated with adjusted hazard ratios of 1.22 (95% confidence interval [CI] 1.14 to 1.31) for all-cause mortality, 1.17 (95% CI 1.07 to 1.28) for CV deaths, and 1.18 (95% CI 1.03 to 1.35) for CHD deaths; in men, adjusted hazard ratios were 1.29 (95% CI 1.20 to 1.38) for all-cause mortality, 1.27 (95% CI 1.17 to 1.37) for CV deaths, and 1.25 (95% CI 1.13 to 1.39) for CHD deaths (p <0.05 for all). In conclusion, blacks and men have significantly greater RCDWs compared to whites and women. Greater RCDW is associated with a greater risk of mortality in men compared to women, whereas no effect modification is observed by ethnicity.

Red cell distribution width and risk of peripheral artery disease: Analysis of National Health and Nutrition Examination Survey 1999–2004

Red cell distribution width (RDW) is an independent predictor of the 10-year estimated risk of coronary heart disease (CHD) events. However, RDW’s association with peripheral artery disease (PAD) – a CHD risk equivalent – has not been evaluated to date. In this cross-sectional study, we examined 6950 participants of the National Health and Nutrition Examination Survey, 1999–2004. PAD was defined as an ankle–brachial index below 0.9 ( n = 618). RDW was divided into quartiles (Q) (Q1: ≤ 12.2; Q2: 12.3–12.5; Q3: 12.6–13.0; Q4: ≥ 13.1) and PAD risk was compared across these quartiles using adjusted multivariate logistic regression. A graded increase in prevalent PAD with increasing RDW quartiles was observed (4.2% in Q1 vs 13.9% in Q4; test of trend p < 0.001). Risk of PAD was significantly higher (odds ratio (OR) 1.19, 95% confidence interval (CI): 1.06–1.34; p = 0.003) after adjusting for age, sex, race, body mass index, hypertension, hyperlipidemia, diabetes, smoking, estimated glomerular filtration rate, C-reactive protein, hemoglobin, mean corpuscular volume, and nutritional factors (folate, iron and vitamin B12) deficiencies with each unit (0.1) increase in RDW. Upon receiver-operating characteristics analysis, the predictive accuracy of the American College of Cardiology / American Heart Association (ACC/AHA)-defined PAD screening criteria (for a high-risk population) was 0.657 at best, but improved significantly (0.727) after addition of RDW ( p < 0.0001). In conclusion, higher levels of RDW are independently associated with a higher risk of PAD and can significantly improve the risk prediction beyond that estimated by ACC/AHA-defined PAD screening criteria.