Is Red Cell Distribution Width a Reliable Marker for Cardiovascular Diseases? A Narrative Review

Red cell distribution width (RDW) is an easy-to-access marker which is routinely measured in complete blood count (CBC) test. Besides the classic use of RDW as a marker for discriminating different types of anemia, recent studies had indicated the relationship between high RDW and cardiovascular diseases. High RDW is not only useful in the diagnosis and prognostication of various cardiovascular conditions but also could be used as a valuable tool for predicting the incidence of cardiovascular diseases. population-based studies have indicated that higher RDW could effectively predict the incidence of heart failure (HF), atherosclerotic diseases, and atrial fibrillation (AF). It has been also demonstrated that higher RDW is associated with worse outcomes in these diseases. Recent studies have shown that high RDW is also associated with other cardiovascular conditions including cardiomyopathies, and pulmonary hypertension. The predictive role of RDW in endovascular interventions has also been demonstrated by many recent studies. Here in this review, we attempt to compile the most recent findings with older reports regarding the relation between high RDW and HF, cardiomyopathies, pulmonary hypertension, AF, atherosclerotic disorders, primary hypertension, and the outcomes of endovascular interventions. we also discussed the role of RDW in the prognostication of different cardiovascular conditions when combined with classic classification criteria.

Red Cell Distribution Width and Mean Corpuscular Volume Alterations: Detecting Inflammation Early in Occupational Cement Dust Exposure

Introduction Cement dust emitted during cement manufacture consists of toxic components. Occupational cement dust exposure may cause inflammation in the human body, which may be detected early by observing changes in blood parameters such as red blood cell distribution width (RDW) and mean corpuscular volume (MCV). Objectives The study aims to observe the effect of occupational cement dust exposure on RDW and MCV. Methods This study was performed in the Department of Physiology of Dhaka Medical College, Dhaka, Bangladesh, and a factory in Munshiganj, Bangladesh, from September 2017 to August 2018. Ninety-two participants between 20 and 50 years were included (46 subjects were occupationally exposed to cement dust, and 46 were not exposed to cement dust). A pre-designed questionnaire was used for data collection. An independent sample t-test was used to analyze basic information, such as blood pressure and BMI. The multivariate regression model was used to analyze the effect of cement dust exposure on the study group. The impact of cement dust exposure duration was analyzed using the multivariate regression model. The level of significance was p < 0.05. The statistical analysis was performed using STATA-15 (StataCorp, College Station, TX), and the graphical presentation used GraphPad Prism v8.3.2. Results The cement dust-exposed participants had a significantly higher value of MCV by 1.19 fi (95% CI = 0.02, 4.84; p = 0.049) and a 5.92% increase in RDW (95% CI = 5.29, 6.55; p < 0.001) than that of the control group. Conclusion The study reveals that exposure to cement dust causes significant changes in RDW and MCV. These changes may indicate hemolysis due to inflammation.

Association between red cell distribution width-and-albumin ratio and the risk of peripheral artery disease in patients with diabetes

Aim

The aim of this study is to explore the association between red blood cell distribution width-to-albumin ratio (RAR) and the risk of peripheral artery disease (PAD) in patients with diabetes.

Methods

This cross-sectional study extracted the data of 1,125 participants with diabetes from the National Health and Nutrition Examination Survey database. A weighted univariable logistic regression model was used to explore variables associated with PAD. With PAD as the outcome variable, a weighted logistic regression model was established. The odds ratio (OR) and 95% confidence interval (CI) were effect size.

Results

After adjusting for covariates, the risk of PAD in patients with diabetes was observed in those with higher RAR (OR = 1.83; 95% CI: 1.06-3.15). In addition, RAR ≥3.25 was related to increased risk of PAD in patients with diabetes (OR = 2.04; 95% CI: 1.05-3.95). In people with diabetes aged ≥65, RAR was a risk factor for PAD with an OR value of 2.67 (95% CI: 1.30-5.46). RAR ≥3.25 was associated with increased risk of PAD (OR = 3.06; 95% CI: 1.15-8.11) relative to RAR <2.80. In people with diabetes who smoked, the risk of PAD was elevated in those with RAR ≥3.25 (OR = 2.85; 95% CI: 1.28-6.32). As for patients with cardiovascular disease, the risk of PAD was elevated as the increase of RAR (OR = 2.31; 95% CI: 1.05-5.10). RAR ≥3.25 was correlated with increased risk of PAD (OR = 3.75; 95% CI: 1.42-9.87). The area under the curve of RAR for the risk of PAD in patients with diabetes was 0.631 (95% CI: 0.588-0.675).

Conclusion

A higher RAR was related to increased risk of PAD in patients with diabetes. The findings might offer a reference for the management of PAD in patients with diabetes.

Lower omega-3 status associated with higher erythrocyte distribution width and neutrophil-lymphocyte ratio in UK Biobank cohort

High red blood distribution width (RDW) is associated with decreased red blood cell deformability, and high neutrophil-lymphocyte ratio (NLR) is a biomarker of systemic inflammation and innate-adaptive immune system imbalance. Both RDW and NLR are predictors of chronic disease risk and mortality. Omega-3 index (O3I) values have previously been shown to be inversely associated with RDW and NLR levels. Our objective was to determine if total plasma long chain omega-3 fatty acids (Omega3%) measured in the UK Biobank cohort were associated with RDW and NLR values. RDW- and NLR- relationships with Omega3% were characterized in 109,191 adults (58.4% female). RDW- and NLR-Omega3% relationships were inversely associated with Omega3% (both p < 0.0001). These cross-sectional associations confirm previous findings that increasing RDW and NLR values are associated with low O3I. The hypothesis that RDW and/or NLR values can be reduced in individuals with less-than optimal long chain omega 3 values need to be tested in randomized controlled intervention trials using EPA and/or DHA.

A Proinflammatory Diet Is Associated with Higher Risk of Peripheral Artery Disease

Peripheral arterial disease (PAD) has a strong relationship with inflammation. However, it is unclear whether the dietary inflammatory potential is associated with PAD. We aimed to address this knowledge gap. The dietary inflammatory index (DII) was obtained using a 24-h dietary recall interview for each individual. Logistic regression models and restricted cubic spline were performed to assess the relationship of DII with the prevalence of PAD. In addition, Spearman correlation analysis and subgroup analysis were also undertaken. In total, 5840 individuals from the 1999–2004 National Health and Nutrition Examination Survey (NHANES) were enrolled in our study. Participants in higher DII quartile tended to have higher rates of PAD. The increase in DII scores showed a positive association with PAD after fully multivariate adjustment (OR (odds ratios) = 1.094, 95% confidence interval (CI): 1.022–1.171). The multivariable-adjusted OR and 95% CI of the highest DII index quartile compared with the lowest quartile was 1.543 (95% CI: 1.116–2.133). Subgroup analysis demonstrated that the positive association between DII and PAD was persistent across population subgroups. In conclusion, we report that a proinflammatory dietary pattern is related to a higher risk of developing PAD among US adults.

Red cell distribution width is associated with cardiovascular risk in adults

Red cell distribution width (RDW) is a measure of erythrocyte size variability. Recent studies have shown that RDW is a predictive, and prognostic marker of mortality and cardiovascular (CVD) events in the general population and in CVD patients. This study aimed to investigate the association between RDW and CVD risk in a large sample of adults. A subsample of CVD free participants of the ELSA-Brasil cohort were included (n=4,481). In the cross-sectional approach, multiple regression analysis was used to investigate the association between RDW and the Framingham Risk Score (FRS). Linear mixed effect model evaluated whether baseline RDW predicted changes in CVD risk after about four-year follow up. Cross-sectional analysis showed that RDW was independently associated with FRS, participants in the fourth-quartile of RDW distribution had a 29% higher FRS than those in the first-quartile RDW (p<0.001). A longitudinal analysis revealed that RDW remained associated with increased FRS. In this large cohort of adult Brazilians, RDW was independently associated with increased CVD risk, as measured by the FRS, both at baseline and after four-year follow-up. However, RDW did not predict change in CVD risk in this short-term follow up.

Potential Prognostic Indicators for Patients With Retinal Vein Occlusion

The second most prevalent cause of retinal vascular disease is retinal vein occlusion (RVO). RVO raises intravascular pressure in the capillary and veins, triggering vessel barrier collapse and subsequent leaking of blood or plasma components into the tissue (edema). Macular edema (ME) is a major complication of RVO that results in significant visual impairment. Laser therapy, intravitreal steroid injections, and vascular endothelial growth factor (VEGF) inhibitors are the major therapeutic techniques. Different therapies reduce ME of RVO and improve visual activity. However, some people have no impact on the resolution of ME, while others have a poor visual prognosis despite full ME cure. There are many investigators who studied the relationship between indicators of various instruments with visual activity. However, a summary of those findings is currently lacking. Therefore, we will focus on the predictive factors of different studies associated with positive visual activity outcomes, which would be very useful and important to help address both treatment expectations and methods for patients with RVO.

Supervised Cycling Training Improves Erythrocyte Rheology in Individuals With Peripheral Arterial Disease

Peripheral arterial disease (PAD) results in insufficient flow to lower extremities. Aerobic exercise provides health benefits for individuals with PAD, but basic science behind it is still debated. Twenty-one PAD patients aged about 70 years with female/male as 7/14 were recruited. Among them, 11 were randomized to have supervised cycling training (SCT) and 10 to receive general healthcare (GHC) as controls. SCT participants completed 36 sessions of SCT at the first ventilation threshold within 12 weeks and the controls received GHC for 12 weeks. Ankle-brachial index (ABI), 6-min walk test (6MWT), peak oxygen consumption (V˙O_2peak), minute ventilation (V˙_E), minute carbon dioxide production (V˙CO₂), erythrocyte rheology, including the maximal elongation index (EI_max) and shear stress at 50% of maximal elongation (SS_1/2), and the Short Form-36 (SF-36) questionnaire for quality of life (QoL) were assessed before and 12 weeks after initial visit. SCT significantly decreased the SS_1/2 as well as SS_1/2 to EI_max ratio (SS_1/2/EI_max) and increased the erythrocyte osmolality in the hypertonic region as well as the area under EI-osmolality curve. The supervised exercise-induced improvement of erythrocyte deformability could contribute to the increased peripheral tissue O₂ delivery and was possibly related with increased V˙O_2peak. The physiological benefit was associated with significantly increased ABI, 6-min walking distance, cardiorespiratory fitness, and SF-36 score. However, no significant changes in aerobic capacity and erythrocyte rheological properties were observed after 12-week of GHC. In conclusion, SCT improves aerobic capacity by enhancing erythrocyte membrane deformability and consequently promotes QoL in PAD patients.

The Relationship between Red Cell Distribution Width and Residual SYNTAX Scores in ST-Segment Elevation Myocardial Infarction Patients after Percutaneous Coronary Intervention

OBJECTIVE

Residual SYNTAX score (rSS) values have been suggested to serve as an independent predictor of mortality in ST-segment elevation myocardial infarction (STEMI) patients following percutaneous coronary intervention (PCI). Prior work has also indicated that red cell distribution width (RDW) can predict the incidence of major adverse cardiac events (MACEs) in STEMI patients. As such, we sought to explore the relationship between RDW and rSS in STEMI patients that have undergone PCI.

METHODS

In total, 456 eligible patients were recruited for this study. Youden's index was used to calculate the optimal RDW cut-off value, after which the relationship between RDW and rSS values was assessed through Spearman's correlation analyses. Independent predictors of high rSS levels were then identified via multivariate logistic regression analysis.

RESULTS

Patients were separated into two groups based upon whether they exhibited high RDW levels (>13.9, Group 1) or low RDW levels (<13.9, Group 2). The average rSS value of patients in Group 2 was found to be significantly decreased compared to patients in Group 1 (P < 0.001). RDW values were found to be positively correlated with rSS (r = 0.604, P < 0.001), and multivariate logistic regression analysis determined that high RDW levels were independently predictive of higher rSS (OR = 27.1 [14.8-51.7]; P < 0.001). Additionally, a nomogram incorporating RDW exhibited good calibration, discriminative capacity, and clinical utility.

CONCLUSIONS

In summary, RDW is strongly correlated with rSS in STEMI patients following PCI, with high RDW levels serving as an independent predictor of high rSS in this patient population.

Red Cell Distribution Width: Commonly Performed Test Predicts Mortality in Primary Total Joint Arthroplasty

INTRODUCTION

Mortality after total joint arthroplasty (TJA) has been thoroughly explored. Short and long-term mortality appear to be correlated with patient comorbidities. Red Cell Distribution Width (RDW) is a commonly performed test that reflects the variation in red blood cell size. This study investigated the utility of RDW, when combined with comorbidity indices, in predicting mortality after TJA.

METHODS

Using a single institutional database, 30,437 primary TJA were identified. Patient demographics (age, gender, body mass index (BMI), pre-operative hemoglobin, RDW, and Charlson Comorbidity Index(CCI)) were queried. The primary outcome was 1-year mortality after TJA. Anemia was defined as hemoglobin <12g/dL for women and <13 g/dL for men. The normal range for RDW is 11.5-14.5%. A preliminary analysis assessed the bivariate association between demographics, preoperative anemia, RDW, CCI, and all-cause mortality within 1-year after TJA. A multivariate regression model was conducted to determine independent predictors of 1-year mortality. Finally, ROC curves were used to compare AUC of RDW, CCI and the combination of both in predicting 1-year mortality.

RESULTS

The mean RDW was 13.6% ± 1.2. Eighteen percent of patients had pre-operative anemia. The mean CCI was 0.4 ± 0.9. RDW, anemia, CCI, and age were significantly associated with a higher incidence of 1-year mortality. RDW, CCI, age, and male sex were found to be independent risk factors for 1-year mortality. RDW (AUC = 0.68) was a better predictor of mortality compared to CCI (AUC = 0.66). The combination of RDW and CCI (AUC = 0.76) predicted 1-year mortality more accurately than CCI or RDW alone.

CONCLUSION

RDW appears to be a useful parameter that, when combined with CCI, can predict the risk for 1-year mortality after TJA.

Association Between Red Cell Distribution Width and Hospital Mortality in Patients with Sepsis

Objective

Sepsis is the leading cause of death in patients admitted to adult intensive care units (ICUs). We aimed to determine the predictive value of red blood cell distribution width (RDW) in patients with sepsis in a large cohort.

Methods

This retrospective observational study used data from the eICU Collaborative Research Database. The prognostic value of RDW was investigated using the receiver operating characteristic (ROC) curve, multiple logistic regression model, integrated discriminatory index (IDI), and net reclassification index (NRI).

Results

In total, 9743 patients were included. The area under the ROC curve of the RDW for predicting hospital mortality was 0.631 (95% confidence interval [CI]: 0.616–0.645). Based on the multiple logistic regression model, an RDW of ≥14.5% was correlated with hospital mortality, regardless of Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation IV (APACHE IV) scores (odds ratio [OR]: 1.838, 95% CI: 1.598–2.119). Using SOFA and APACHE IV scores as reference, the IDI and continuous NRI of RDW for hospital mortality was about 0.3 and 0.014, respectively.

Conclusions

The RDW may be useful in predicting hospital mortality in patients with sepsis, offering extra prognostic value beyond SOFA and APACHE IV scores.

The association of cadmium and lead exposures with red cell distribution width

Elevated red blood cell distribution width (RDW), traditionally an indicator of anemia, has now been recognized as a risk marker for cardiovascular disease incidence and mortality. Experimental and acute exposure studies suggest that cadmium and lead individually affect red blood cell production; however, associations between environmental exposures and RDW have not been explored. We evaluated relationships of environmental cadmium and lead exposures to RDW. We used data from 24,607 participants aged ≥20 years in the National Health and Nutrition Examination Survey (2003-2016) with information on blood concentrations of cadmium and lead, RDW and socio-demographic factors. In models adjusted for age, sex, race/ethnicity, education, poverty income ratio, BMI, alcohol consumption, smoking status and serum cotinine, RDW was increasingly elevated across progressively higher quartiles of blood cadmium concentration. A doubling of cadmium concentration was associated with 0.16 higher RDW (95% CI: 0.14, 0.18) and a doubling of lead concentration with 0.04 higher RDW (95% CI: 0.01, 0.06). Also, higher cadmium and lead concentrations were associated with increased odds of high RDW (RDW>14.8%). The associations were more pronounced in women and those with low-to-normal mean corpuscular volume (MCV) and held even after controlling for iron, folate or vitamin B12 deficiencies. In analysis including both metals, cadmium remained associated with RDW, whereas the corresponding association for lead was substantially attenuated. In this general population sample, blood cadmium and lead exposures were positively associated with RDW. The associations may indicate hemolytic or erythropoietic mechanisms by which exposure increases mortality risk.

Red Cell Distribution Width as a Novel Predictor of Mortality and Complications After Primary Shoulder Arthroplasty

INTRODUCTION

Variability in red blood cell volume can occur in disease states and is quantified using a simple equation, yielding the relative distribution of width (RDW). Recent literature has correlated RDW with outcomes in many cardiac disease states, hip fractures, and even revision hip arthroplasty. The association with outcomes in total shoulder arthroplasty (TSA) is yet to be delineated. The purpose of this study was to investigate the possible relationship between preoperative RDW levels and mortality and other adverse outcomes after primary TSA.

METHODS

Patients who underwent primary TSA and had RDW values on record were identified in a national database. Patients were then grouped by RDW, and the incidence of complications was calculated for each group, including mortality within 1 year, periprosthetic infection within 1 year, acute venous thromboembolism within 30 days, and readmission to a hospital within 30 days. A threshold value of RDW for increased complications was established using receiver operator characteristic (ROC) curves.

RESULTS

Five thousand two hundred forty-five patients who underwent TSA with a recorded RDW were included in the study. An RDW cutoff of 16% was found to be significantly associated with mortality at 1 year (P < 0.0001), readmission (P < 0.0001), and infection (P = 0.013) on ROC analysis. When controlling for demographic and comorbidity values, a high RDW was markedly associated with a higher mortality rate (odds ratio 2.0, 95% confidence interval 18 to 2.2) and readmission rate (odds ratio 1.5, 95% confidence interval 1.3 to 1.8). A high RDW was not markedly associated with increased infection or venous thromboembolism rate in the multivariate analysis.

DISCUSSION

Increasing preoperative RDW is associated with increasing complication rates after TSA. This value can be used as an indirect, real-time preoperative predictor of adverse outcomes and most importantly one-year mortality and hospital readmission.

LEVEL OF EVIDENCE

III retrospective cohort study.

Validation of randomized controlled trial-derived models for the prediction of postintervention outcomes in chronic limb-threatening ischemia

BACKGROUND

Chronic limb-threatening ischemia (CLTI) represents the most severe form of peripheral artery disease and has a large impact on quality of life, morbidity, and mortality. Interventions are aimed at improving tissue perfusion and averting amputation and secondary cardiovascular complications with an optimal risk-benefit ratio. Several prediction models regarding postprocedural outcomes in CLTI patients have been developed on the basis of randomized controlled trials to improve clinical decision-making. We aimed to determine model performance in predicting clinical outcomes in selected CLTI cohorts.

METHODS

This study validated the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL), Finland National Vascular registry (FINNVASC), and Prevention of Infrainguinal Vein Graft Failure (PREVENT III) models in data sets from a peripheral artery disease registry study (Athero-Express) and two randomized controlled trials of CLTI in The Netherlands, Rejuvenating Endothelial Progenitor Cells via Transcutaneous Intra-arterial Supplementation (JUVENTAS) and Percutaneous Transluminal Angioplasty and Drug-eluting Stents for Infrapopliteal Lesions in Critical Limb Ischemia (PADI). Receiver operating characteristic (ROC) curve analysis was used to calculate their predictive capacity. The primary outcome was amputation-free survival (AFS); secondary outcomes were all-cause mortality and amputation at 12 months after intervention.

RESULTS

The BASIL and PREVENT III models showed predictive values regarding postintervention mortality in the JUVENTAS cohort with an area under the ROC curve (AUC) of 81% and 70%, respectively. Prediction of AFS was poor to fair (AUC, 0.60-0.71) for all models in each population, with the highest predictive value of 71% for the BASIL model in the JUVENTAS population. The FINNVASC model showed the highest predictive value regarding amputation risk in the PADI population with AUC of 78% at 12 months.

CONCLUSIONS

In general, all models performed poor to fair in predicting mortality and amputation. Because the BASIL model performed best in predicting AFS, we propose use of the BASIL model to aid in the clinical decision-making process in CLTI. However, improvements in performance have to be made for any of these models to be of real additional value in clinical practice.

The role of red blood cell distribution width (RDW) in cardiovascular risk assessment: useful or hype?

Red blood cell distribution width (RDW) reflects erythrocyte size distribution, thus representing a reliable index of anisocytosis, widely used for the differential diagnosis of micro- and normocytic anaemias. Along with the large use in diagnostic hematology, RDW has been associated with presence and complications of a vast array of human pathologies during the last decades, including cardiovascular (CV) diseases. This article is hence aimed to provide an overview of important studies and systematic reviews with meta-analysis, in which RDW has been associated with CV events and mortality, in the attempt of establishing whether enough evidence exists for supporting its routine use in clinical practice. According to available data it seems reasonable to conclude that although the diagnostic specificity is low, and this measure is still plagued by important lack of standardization, RDW can be regarded as an index of enhanced patient fragility and higher vulnerability to adverse outcomes. Abnormal RDW values shall hence persuade physicians to broaden the diagnostic reasoning over anaemias, especially those due to malnutrition or malabsorption, encompassing a comprehensive assessment of traditional and non-traditional CV risk factors.

Complete blood count parameters in peripheral arterial disease

Objective: To determine whether complete blood count parameters could be used as the biomarkers of inflammation in patients with in peripheral arterial disease. Methods: Seventy-five patients with peripheral arterial disease (study group) and 75 healthy subjects (control group) were included in this retrospective study. Their baseline clinical characteristics and laboratory data were recorded and compared. Data were compared using univariate tests including independent samples t-test, Mann-Whitney U-test and chi-square test. Moreover, multivariate logistic regression analysis was also conducted to determine independent predictors of peripheral arterial disease. Results: The groups were statistically similar with regards to baseline clinical and demographic features. The values of C-reactive protein, white blood cell and neutrophil-to-lymphocyte ratio values were found to be statistically significantly higher in study group versus control group, but none of them were considered as an independent predictor of peripheral arterial disease according to multivariate logistic regression analysis. Only mean platelet volume was demonstrated to be a statistically significant predictor of peripheral arterial disease. Conclusion: Our study deduced that mean platelet volume was an independent predictor of peripheral arterial disease, and could be used as a marker of inflammation in patients with peripheral arterial disease.

Correlation Between Red Cell Distribution Width and Peripheral Vascular Disease Severity and Complexity

A traditional hematological marker, red cell distribution width (RDW), is accepted as a novel marker of atherosclerotic vascular diseases. Clinical importance of the RDW as a prognostic biomarker in peripheral vascular disease (PVD) has been reported in a few studies. Herein, we aimed to show the correlation between RDW and PVD severity and its complexity in terms of angiographic evaluation. A total of 118 patients who underwent peripheral lower extremity angiography were subsequently evaluated retrospectively. Upon admission, RDW level was measured with automated complete blood count. Severity and complexity of the PVD was evaluated according to Trans-Atlantic Inter-Society Consensus (TASC II) classification. A TASC II A-B lesion was defined as simple PVD, and a TASC II C-D lesion was defined as prevalent and complex PVD. Then, both groups were compared statistically according to clinical, laboratory, and demographic features, including RDW levels. In 49.6% of the patients, TASC II C-D lesions were observed. Advanced age, male gender, and body mass index (BMI) were associated with TASC II groups. Red cell distribution width levels were correlated with presence of PVD, as well as TASC II grades (p:0.02). The fourth quartile (75th percentile) of the RDW levels was 14.1, and patients with RDW levels ≥14.1 had a more significant correlation with the presence and severity of PVD (p:0.001). In the multivariate regression analysis, elevated RDW was found to be an independent predictor of the presence of PVD and also TASC II C-D lesions (OR:2.26, with a 95% confidence interval (CI) 0.051-0.774; p:0.02). Elevated RDW levels was associated with TASC II C-D lesions, which indicated more prevalent and complex PVD.

The diagnostic and prognostic value of red cell distribution width in cardiovascular disease; current status and prospective

The red blood cell distribution width (RDW) is an index of the heterogeneity of circulating red blood cell size, which along with other standard complete blood count (CBC) parameters are used to identify hematological system diseases. Besides hematological disorders, several clinical studies have shown that an increased in the RDW may be associated with other diseases including acute pancreatitis, chronic kidney disease, gastrointestinal disorders, cancer, and of special interest in this review, cardiovascular disease (CVD). The diagnostic and prognostic value of RDW in different CVD (acute coronary syndrome, ischemic cerebrovascular disease, peripheral artery disease, atrial fibrillation, heart failure, and acute ischemic stroke) has been reviewed in this article, to provide an understanding how its measurement may be applied to improve the management of these conditions.

Predicting the Severity of Acute Pancreatitis With Red Cell Distribution Width at Early Admission Stage

Red cell distribution width (RDW) has been proposed as an early prognosis marker with increased mortality in variety of pathophysiological conditions. We hypothesized that elevated RDW could be used in judging the severity of acute pancreatitis (AP). We retrospectively and prospectively studied 545 and 72 AP patients, who were admitted to the Shanghai Tenth People's Hospital of Tongji University, respectively. Compared with mild acute pancreatitis, significantly higher RDW was observed in patients with moderately severe acute pancreatitis and sever acute pancreatitis (14.03 ± 1.74% vs. 13.23 ± 1.23%, P < 0.000). RDW values were also found positively correlated with the patient's blood urea nitrogen (r = 0.120, P = 0.026), creatinine (r = 0.182, P = 0.000), age (r = 0.099, P = 0.028), and bedside index of severity in acute pancreatitis scoring system (r = 0.147, P = 0.001), and were negatively correlated with the serum albumin (r = -0.244, P = 0.000). The area under the receiver-operating characteristics was as follows-RDW: 0.677 (95% confidence interval [CI], 0.619-0.735, P < 0.000); combination of RDW and albumin: 0.693 (95% CI, 0.625-0.761, P < 0.000); and the optimal cutoff value for RDW to predict whether patients with AP should be in intensive care unit (ICU) was 13.55 with a sensitivity of 54.5% and a specificity of 73.6%. In the validation study, AP with RDW ≥ 13.55% had significantly higher ICU admission ratio than those with RDW < 13.55% (44.4% vs. 9.8%, P < 0.000). In conclusion, RDW is positively associated with AP severity, and is likely a useful predictive parameter of AP severity.

Prognostic Value of Preoperative Red Cell Distribution Width: Fine-Tuning by Mean Corpuscular Volume

BACKGROUND

Abnormal red cell distribution width (RDW), reflecting heterogeneity of red blood cell (RBC) size, is associated with cardiovascular disease outcomes. However, whether RBC size itself, expressed as mean corpuscular volume (MCV), provides additional prognostic value is unclear. We therefore investigated the relationship between outcomes after cardiac surgery and both RDW and MCV simultaneously.

METHODS

From January 2010 to January 2014, 16,097 patients underwent cardiac surgery at Cleveland Clinic and had complete blood count findings available for analysis. Outcomes included RBC transfusion, postoperative complications, and intensive care unit (ICU) and postoperative hospital lengths of stay. Risk-adjusted associations of RDW and MCV with outcomes and their relative importance in predicting outcome were identified by random forest machine learning.

RESULTS

High RDW was associated with more RBC transfusions. Except for postoperative atrial fibrillation, risks of complications and ICU and postoperative lengths of stay were at their minimum when RDW was normal, 13% to 14%. The relationship of MCV to complications was U-shaped: high (macrocytosis) and low (microcytosis) values were associated with higher risk. RDW was an important risk factor for most postoperative outcomes and lengths of stay; MCV was less so, but provided prognostic value in addition to RDW alone, particularly when there was macrocytosis.

CONCLUSIONS

Abnormal RDW and MCV are associated with higher risk of transfusion and postoperative outcomes after cardiac surgery. RDW is one of the most important variables in predicting outcomes, but MCV provides additional prognostic value. Both should be taken into consideration when estimating the perioperative risk of patients undergoing cardiac surgery.

Red Cell Distribution Width: An Unacknowledged Predictor of Mortality and Adverse Outcomes Following Revision Arthroplasty

BACKGROUND

Revision total joint arthroplasties (TJAs) have been empirically associated with significant postoperative morbidity and mortality. Red blood cell distribution width (RDW), a frequently measured hematological parameter, has been shown to predict mortality in hip fracture patients. However, its utility in risk-stratifying patients before revision TJA remains unknown. The aim of this study was to investigate the possible relationship between preoperative RDW levels and outcome of revision arthroplasty in terms of mortality, adverse outcomes, and length of hospital stay.

METHODS

A single-institution retrospective study was conducted on 4633 patients who underwent revision TJA (3289 hips and 1344 knees) between 2000 and September 2016. Of those, 656 (14.1%) surgeries were performed due to periprosthetic joint infection, and 3977 (85.9%) were aseptic revisions. The association between preoperative RDW and various outcomes, including 1-year mortality, in-hospital medical complications, length of hospital stay, and 90-day all-cause readmission, was examined.

RESULTS

The average age of patients in the cohort was 65.4 ± 12.9 years. The average Charlson comorbidity index was 0.6 (standard deviation = 1.0), with 691 patients (14.9%) having 2 or more comorbidities. Mean preoperative RDW level was 14.4% (standard deviation = 1.8). After adjusting for covariates, higher RDW levels were statistically significantly associated with mortality (adjusted odds ratio [OR], 1.25; 95% confidence interval [CI], 1.13-1.39; P < .001), any in-hospital medical complications (adjusted OR, 1.12; 95% CI, 1.07-1.18; P < .001), and readmission (adjusted OR, 1.07; 95% CI, 1.02-1.13; P < .001).

CONCLUSION

Higher levels of preoperative RDW appeared to be associated with less optimal outcomes after revision TJA. Adult reconstruction orthopedic surgeons should be aware of this predictive factor and exercise caution with TJA revision patients with high values of preoperative RDW. RDW could be included in the routine perioperative workup and used to counsel patients on their postoperative risk.

Diagnostic and Prognostic Relevance of Red Blood Cell Distribution Width for Vascular Aging and Cardiovascular Diseases

Evidence suggests association of red blood cell distribution width (RDW) with cardiovascular diseases (CVDs). On the contrary, we underline that the sole RDW values cannot represent a valid CVD biomarker. High RDW values are expression of biological effects of a lot of both endogenous and exogenous factors (i.e., age, sex, genetic background, inflammation, hormones, drugs, diet, exercise, hematological analyzers, and ranges of values), modulating the biology and physiology of erythrocytes. Thus, the singular monitoring of RDW cannot be used to predict cardiovascular disorders. Accordingly, we have reviewed the evidence for potential relationship of RDW values with alterations in the cardiovascular system (i.e., regenerative capacity, endothelial turnover, and senescence of cardiovascular cells), associated with vascular aging and disease. In addition, we highlight the inevitable impact of biases in clinical application of RDW related to CVDs. Based on our thorough review of literature, we suggest a combined evaluation of RDW with other emerging biomarkers related to vascular aging and the diagnosis and prognosis of CVDs, including telomere length of leukocytes, circulating nucleated red blood cells (nRBCs) and endothelial progenitor cells (EPCs) in future large scale studies.

Red cell distribution width at hospital discharge and out-of hospital outcomes in critically ill non-cardiac vascular surgery patients

Objective

Red cell distribution width (RDW) is associated with mortality and bloodstream infection risk in the critically ill. In vascular surgery patients surviving critical care it is not known if RDW can predict subsequent risk of all-cause mortality following hospital discharge. We hypothesized that an increase in RDW at hospital discharge in vascular surgery patients who received critical care would be associated with increased mortality following hospital discharge.

Design, setting, and participants

We performed a two-center observational cohort study of critically ill non-cardiac vascular surgery patients surviving admission 18 years or older treated between November, 1997, and December 2012 in Boston, Massachusetts.

Exposures

RDW measured within 24 hours of hospital discharge and categorized a priori as ≤13.3%, 13.3–14.0%, 14.0–14.7%, 14.7–15.8%, >15.8%.

Main outcomes and measures

The primary outcome was all cause mortality in the 90 days following hospital discharge.

Results

The cohort included 4,715 patients (male 58%; white 83%; mean age 62.9 years). 90 and 365-day post discharge mortality was 7.5% and 14.4% respectively. In the cohort, 47.3% were discharged to a care facility and 14.8% of patients were readmitted within 30 days. After adjustment for age, gender, race, Deyo-Charlson comorbidity Index, patient type, acute organ failures, prior vascular surgery and vascular surgery category, patients with a discharge RDW 14.7–15.8% or >15.8% have an adjusted OR of 90-day post discharge mortality of 2.52 (95%CI, 1.29–4.90; P = 0.007) or 5.13 (95%CI, 2.70–9.75; P <0.001) relative to patients with a discharge RDW ≤13.3%. The adjusted odds of 30-day readmission in the RDW >15.8% group was 1.52 (95%CI, 1.12–2.07; P = 0.007) relative to patients with a discharge RDW ≤13.3%. Similar adjusted discharge RDW-outcome associations are present at 365 days following hospital discharge and for discharge to a care facility.

Conclusions

In critically ill vascular surgery patients who survive hospitalization, an elevated RDW at hospital discharge is a strong predictor of subsequent mortality, hospital readmission and placement in a care facility. Patients with elevated RDW are at high risk for adverse out of hospital outcomes and may benefit from closer post discharge follow-up and higher intensity rehabilitation.

Dynamic Change of Red Cell Distribution Width Levels in Prediction of Hospital Mortality in Chinese Elderly Patients with Septic Shock

Background:

The normal range of red cell distribution width (RDW) level is <15%. Several studies have indicated that a high RDW level was associated with mortality in critically ill patients, and the patients with a high RDW level need increased focus in clinical practice. In view of the difficulty in defining the specific value of high RDW level, the key is to focus on the patient with the level beyond the normal upper limit. This study aimed to determine whether dynamic change of RDW levels, rather than the level itself, is predictive of death in elderly patients with septic shock when RDW level is beyond 15%.

Methods:

Between September 2013 and September 2015, the elderly septic shock patients with RDW level beyond 15% were enrolled in this study. The RDW levels were measured at enrollment (day 1), and days 4 and 7 after enrollment. Sequential Organ Failure Assessment (SOFA) scores were recorded simultaneously.

Results:

A total of 45 patients, including 32 males and 13 females, were included in the final analysis. Based on their hospital outcomes, these patients were divided into the survivor group (n = 26) and the nonsurvivor group (n = 19). There were no significant differences in age, gender, body mass index, initial level of RDW, Acute Physiology and Chronic Health Evaluation II scores, and SOFA scores between survivors and nonsurvivors. At days 4 and 7 measurement, both RDW level (median [interquartile range]: day 4: 15.8 [2.0]% vs. 16.7 [2.0]%, P = 0.011; and day 7: 15.6 [1.8]% vs. 17.7 [2.5]%, P = 0.001) and SOFA scores (day 4: 7.0 [4.0] vs. 16.0 [5.0], P < 0.001, day 7: 5.5 [4.0] vs. 17.0 [5.0], P < 0.001) were significantly lower in survivors than those in nonsurvivors. Dynamic changes of RDW and SOFA scores in survivor group were significantly different from those in nonsurvivor group (all P < 0.05). Continuous increase in RDW level was observed in 10 of the 13 nonsurvivors, but only in 3 of the 26 survivors. The level of RDW7 and dynamic changes significantly correlated with their counterparts of SOFA scores (all P < 0.05), whereas the levels of RDW1 and RDW4 had no significant correlation with their counterparts of SOFA scores (all P > 0.05).

Conclusions:

Continuous increase in RDW level, rather than the level of RDW itself, was more useful in predicting hospital death in elderly patients with septic shock when the level of RDW was >15%. The dynamic changes of RDW were highly correlated with the SOFA score in the patients.

Association of Red Cell Distribution Width Values with Vision Potential in Retinal Vein Occlusion

PURPOSE

To explore a possible association of red cell distribution width (RDW), a parameter that measures variation in red blood cell size or red blood cell volume and is an index of erythrocyte heterogeneity, with vision in patients with retinal vein occlusion (RVO).

DESIGN

Cross-sectional study.

PARTICIPANTS

Patients with either branch RVO (n = 70) or central RVO (n = 56) and gender-matched controls (n = 67) were included.

METHODS

All participants underwent a comprehensive ophthalmologic examination, including fundus fluorescein angiography and macular OCT (Heidelberg Spectralis; Heidelberg Engineering, Heidelberg, Germany). Exclusion criteria included RVO not confirmed by fluorescein angiography, history of malignancy, anemia, follow-up of less than 6 months, and unavailability of RDW value within 3 months of first presentation of RVO. Retinal vein occlusion patients were divided into 4 quartiles according to RDW value: quartile 1 (RDW ≤ 13.8%), quartile 2 (13.8% < RDW ≤ 14.8%), quartile 3 (14.8% < RDW ≤ 16.0%), and quartile 4 (RDW > 16.0%). Unpaired samples t tests, Pearson correlation tests, chi-square tests, analyses of variance, and multiple regression analyses were used for statistical evaluation.

MAIN OUTCOME MEASURES

Red cell distribution width value and best-corrected visual acuity (BCVA).

RESULTS

There was no significant difference in the demographics of participants in all 3 groups with respect to age, gender, and associated systemic diseases. Red cell distribution width was significantly higher in RVO patients (14.9±1.6 μm) compared with control participants (12.5±1.4 μm; P<0.0001). There was a statistically significant correlation between RDW value and both initial BCVA (r = 0.443; P<0.0001) and final BCVA (r = 0.379; P<0.0001) in RVO patients. Both initial and final BCVA were better in RDW quartiles 1 and 2 compared with RDW quartiles 3 and 4.

CONCLUSIONS

Red cell distribution width was significantly higher in RVO patients compared with control participants. Furthermore, higher RDW value was associated with lower initial and final BCVA. Red cell distribution width merits further studies related to being a potential prognostic factor for vision in RVO patients.

Is there a Real Correlation between Red Cell Distribution Width and Peripheral Arterial Disease?

Background

Few data is available concerning the association between peripheral arterial disease (PAD) and red cell distribution width (RDW). In this study, we analyzed the relationship between RDW and atherosclerosis of the vessels other than coronary arteries in patients who had undergone digital substraction angiography (DSA).

Methods

This study included 730 patients who had undergone DSA. Patients were divided into two groups according to their angiographic images. The association between RDW and atherosclerosis of peripheral arteries was analyzed. The relationship between atherosclerosis and smoking, hypertension (HT), diabetes mellitus (DM), hs-CRP, hemoglobin, white blood cell (WBC), triglyceride, total cholesterol, HDL and LDL cholesterol levels was assessed.

Results

Atherosclerosis was observed more common in male and patients with older age, HT, DM and smoking (p<0.001). hs-CRP and WBC levels were both in significantly positive association with atherosclerosis (p<0.05). However, there were no significant differences in the RDW levels, hemoglobin, triglyceride, total cholesterol, LDL and HDL cholesterol levels in the groups (p>0.05).

Conclusion

Our results seem to demonstrate that older age, male gender, HT, DM and smoking are powerful risk factors for PAD. In contrast to the previous reports, RDW levels are found not to be associated with atherosclerosis of peripheral arteries.

Association of red cell distribution width with all-cause and cardiovascular-specific mortality in African American and white adults: a prospective cohort study

Background

While the mortality rate is declining in the United States, the life expectancy gap among different population groups suggests a need to identify biomarkers to improve early identification of individuals at risk. Red cell distribution width (RDW), a measure of anisocytosis, is an emerging biomarker of chronic disease morbidity and mortality, particularly in the elderly. However, little is known about its association with mortality risk in younger adults. The objectives of this study were to investigate the association between RDW and overall and cause-specific mortality risk, and to identify novel determinants of RDW level.

Methods

We used prospectively collected data from the Healthy Aging in Neighborhoods of Diversity across the Life Span study conducted in Baltimore, Maryland. At baseline (2004–2009), the study recruited 3720 African American and white men and women aged 30–64 years. Participants provided peripheral venous blood for RDW measurement as part of complete blood count, and genotyping. Mortality status was ascertained using the National Death Index database through December 31, 2013. Multivariable adjusted Cox proportional hazards regression models were fitted to assess mortality risk, and multiple linear regression models to identify determinants of RDW level.

Results

Participants’ mean age was 48.1 (9.2) years. Of 2726 participants included in the present analyses, 57% were African Americans, and 56% were women. After 18,424 person-years of follow-up time, there were 226 deaths, and the leading cause of death were cardiovascular diseases (31.9%). Participants in the highest quartile of RDW had a 1.73-fold increased all-cause mortality risk (highest quartile vs. lowest quartile, multivariable adjusted hazard ratio = 1.73, 95% confidence interval: 1.10–2.74, p-trend = 0.006). This effect was significantly modified by body mass index (p-interaction = 0.004). Similar risk was observed for cardiovascular disease-specific mortality. Independent of body mass index, waist-hip ratio and illicit drug use were significantly associated with RDW.

Conclusions

Elevated RDW was associated with a substantial risk of all-cause and cardiovascular disease-specific mortalities that was modified by body mass index. Central obesity and illicit drug use influence RDW level. In vulnerable populations at-risk for health disparities, RDW could provide a useful and inexpensive biomarker of mortality.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1313-6) contains supplementary material, which is available to authorized users.

Brief Report: Elevated Red Cell Distribution Width Identifies Elevated Cardiovascular Disease Risk in Patients With HIV Infection

Red cell distribution width (RDW) is linked to cardiovascular risk in the general population, an association that might be driven by inflammation. Whether this relationship holds for patients with HIV infection has not been previously studied. Using a large clinical registry, we show that elevated RDW (>14.5%) is independently associated with increased risk of coronary artery disease {odds ratio [OR] 1.39 [95% confidence interval (CI): 1.25 to 1.55]}, peripheral vascular disease [OR 1.41 (95% CI: 1.29 to 1.53)], myocardial infarction [1.43 (95% CI: 1.25 to 1.63)], heart failure [OR 2.23 (95% CI: 1.99 to 2.49)], and atrial fibrillation [OR 1.96 (95% CI: 1.64 to 2.33)]. In conclusion, in the context of the inflammatory milieu that accompanies HIV infection, RDW remains a powerful marker of cardiovascular disease.

Predictive value of red blood cell distribution width for coronary artery lesions in patients with Kawasaki disease

Recent studies have shown that elevated red blood cell distribution width is associated with poor outcome in cardiovascular diseases. In order to assess the predictive value of red blood cell distribution width, before treatment with intravenous immunoglobulins, for coronary artery lesions in patient with Kawasaki disease, we compared 83 patients with coronary artery lesions and 339 patients without coronary artery lesions before treatment with intravenous immunoglobulin. Clinical, echocardiographic, and biochemical values were evaluated along with red blood cell distribution width. A total of 422 consecutive patients with Kawasaki disease were enrolled into our study. According to receiver operating characteristic curve analysis, the optimal red blood cell distribution width cut-off value for predicting coronary artery lesions was 14.55% (area under the curve was 0.721; p=0.000); eighty-three patients (19.7%) had coronary artery lesions, and 70% of the patients with coronary artery lesions had red blood cell distribution width level >14.55%. Logistic regression analysis revealed that fever duration >14 days (odds ratio was 3.42, 95% confidence interval was 1.27-9.22; p=0.015), intravenous immunoglobulin resistance (odds ratio was 2.33, 95% confidence interval was 1.02-5.29; p=0.04), and red blood cell distribution width >14.55% (odds ratio was 3.49, 95% confidence interval was 2.01-6.05; p=0.000) were independent predictors of coronary artery lesions in patients with Kawasaki disease. In Conclusion, red blood cell distribution width may be helpful for predicting coronary artery lesions in patients with Kawasaki disease.

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.

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.

Red Blood Cell Distribution Width Is Associated with Severity of Leukoaraiosis

Red blood cell distribution width (RDW) is one of the routine hematologic parameters reported in the complete blood count test, which has been recognized as strong prognostic marker for various medical conditions, especially cardiovascular disease. We evaluated that RDW was also associated with the leukoaraiosis; common radiological finding of brain and that has been strongly associated with risk of stroke and dementia. In the present study, we included 1006 non-stroke individuals who underwent brain MRI and routine complete blood count test including RDW. Fazekas scale was used to measure the severity of leukoaraiosis based on fluid-attenuated inversion recovery image, and the severity was dichotomized to mild-degree (Fazekas scale: 0–1) and severe-degree leukoaraiosis (Fazekas scale: 2–3). Univariate and multivariate logistic regression models were constructed to evaluate independent risk factor for severe-degree of leukoaraiosis. Mean age of 1006 subjects was 64.34 ± 9.11 year, and mean of RDW was 12.97 ± 0.86%. The severe-degree of leukoaraiosis (Fazekas scale ≥ 2) was found in 28.83%. In the multivariate logistic regression, 4^th quartile of RDW (> 13.3%) were significantly associated with the presence of severe-degree of leukoaraiosis (adjusted odds ratio, 1.87; 95% confidence interval, 1.20–2.92) compared to the 1^st quartile of RDW (< 12.5%). The significance was not changed after adjustments for hemoglobin and other hematologic indices. These findings suggest that RDW is independently associated with severity of leukoaraiosis.

Red cell distribution width and mortality in carotid atherosclerosis

BACKGROUND

Red cell distribution width (RDW) is associated with morbidity and mortality in chronic cardiac disease. The aim of the present study was to investigate the role of RDW as a predictor of adverse outcome in patients with carotid atherosclerosis.

MATERIALS AND METHODS

We prospectively studied 1065 of 1286 consecutive patients with neurological asymptomatic carotid artery stenosis as assessed by duplex Doppler sonography. The study end points were all-cause mortality and cardiovascular mortality respectively.

RESULTS

During a median follow-up time of 6·2 years (interquartile range 5·9-6·6), corresponding to 5551 overall person-years, 275 patients (25·8%) died. Of them, 182 patients (66·2%) died due to cardiovascular causes. RDW was significantly associated with adverse outcome. In a continuous multivariate Cox regression analysis, the adjusted hazard ratio for each per cent increase in RDW was 1·39 (95% CI 1·27-1·53; P < 0·001) for all-cause and 1·43 (95% CI 1·28-1·60; P < 0·001) for cardiovascular mortality respectively. Kaplan-Meier estimates showed a gradual relationship between increasing quartiles of RDW and death (log rank P < 0·001). Adjusted hazard ratios for all-cause death ranged from 0·89 to 1·94 for the highest vs. the lowest quartile (P < 0·001 for trend) and for cardiovascular death from 1·08 to 2·34 for the highest vs. the lowest quartile (P < 0·001 for trend) respectively.

CONCLUSIONS

Red cell distribution width was significantly and independently associated with all-cause and cardiovascular death in patients with asymptomatic carotid atherosclerosis.

Red blood cell distribution width and cardiovascular diseases

BACKGROUND

The red blood cell distribution width (RDW) is a rather simple measure of red blood cell (RBC) size heterogeneity (i.e., anisocytosis), which is easily calculated by dividing the standard deviation (SD) of erythrocyte volumes for the mean corpuscular volume (MCV). Emerging evidence suggests that, besides RBC abnormalities, many human disorders may be frequently associated with a high degree of anisocytosis.

METHODS

In this narrative review, we analyzed the current scientific literature about the putative role and the potential epidemiologic association between RDW and cardiovascular diseases. The findings of the most representative epidemiological studies were summarized and discussed.

RESULTS

Overall, considerable and convincing evidence has been brought that an increased RDW value is associated with acute coronary syndrome (ACS) [including acute myocardial infarction (AMI)], ischemic cerebrovascular disease (including stroke), peripheral artery disease (PAD), as well as with atrial fibrillation (AF), heart failure (HF) and hypertension. Higher anisocytosis also significantly and independently predicts adverse outcomes in patients with these conditions.

CONCLUSIONS

Although the role of anisocytosis in the pathogenesis of cardiovascular diseases remains uncertain, the considerable evidence available so far suggests that the clinical use of RDW may be broadened beyond the conventional boundaries of erythrocyte disorders, in particular for assisting the diagnosis and prognostication of patients with ACS, ischemic cerebrovascular disease, PAD, HF and AF.

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.

Hematological Parameters as Predictors of Cardiovascular Disease in Obstructive Sleep Apnea Syndrome Patients

We investigated the role of the red cell distribution width (RDW) and other parameters including platelet (PLT) count, mean platelet volume (MPV), and platelet distribution width (PDW) in patients with obstructive sleep apnea syndrome (OSAS) having cardiovascular diseases (CVDs). Patients (n = 142) having sleep disorders and who applied for a night polysomnography were included in this study. For statistical analysis, chi-square test, bivarite correlation, and logistic and stepwise regression tests were used. A positive correlation between RDW MPV, RDW, and body mass index as well as PLT and apnea-hypopnea index were observed. A negative correlation between AHI and PDW (P= .041) and a positive correlation between AHI and PLT (P= .010) were found in the patients ≥40 years old with CVD. The RDW was higher in patients ≥40 years old who had CVD (P= .016), and 19% of them had RDW >14%. The PDW (odds ratio = 6.02 [95% confidence interval = 1.3-28.2],P= .023) appeared to be associated with increased risk of hyperlipidemia in patients with severe OSAS. If these results are confirmed, RDW could be used with other markers, especially PLT and PDW, in prediction of CVD in patients with severe OSAS.

Red cell distribution width improves the prediction of prognosis after transcatheter aortic valve implantation

OBJECTIVES

The aim of this study was to determine if red cell distribution width (RDW) could improve the prediction of prognosis after transcatheter aortic valve implantation (TAVI).

METHODS

In this single-centre study, 197 consecutive patients underwent TAVI (median age 82 (77-86), 46.2% men). Normal RDW at baseline was defined as ≤15.5%, elevated RDW at baseline was defined as >15.5%. Ouctomes according to the Valve Academic Research Consortium 2 and survival up to one year were compared between these groups.

RESULTS

Compared with the patients with RDW ≤15.5% (n = 168), those with RDW >15.5% (n = 29) had a higher Society of Thoracic Surgeon (STS) score (7.2 vs 5.0%, P = 0.041), higher systolic pulmonary arterial pressure (50 vs 41 mmHg, P = 0.021) and lower haemoglobin (11.5 vs 12.4 mg/dl, P = 0.003). Patients with RDW >15.5% developed significantly more adverse events after TAVI (major vascular complications: 10.3 vs 1.8%, P = 0.042; aortic regurgitation grade II-IV: 50.0 vs 18.0%, P = 0.001) and survival up to 1 year was significantly lower (85.6 vs 65.2%, log-rank: P = 0.007). In addition, RDW >15.5% at baseline was the most significant predictor for mortality (hazard ratio: 2.701 (1.279-5.704), P = 0.009), even when the STS score was added to the model [RDW >15.5%: hazard ratio: 2.276 (1.045-4.954), P = 0.038].

CONCLUSIONS

Elevated RDW is a significant predictor for adverse events and increased 1-year mortality after TAVI. Adding RDW to the classical STS score could be a valuable strategy to improve preoperative risk assessment in potential TAVI candidates.

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 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.

Red cell distribution width as a prognostic indicator in pediatric heart disease and after surgery

Background. Red cell distribution width (RDW) is an important marker which reflects inflammatory activity in many chronic diseases. The objective of this study is to investigate the impact of RDW on morbidity and mortality before and after pediatric congenital heart surgery. Methods. 107 patients with congenital heart disease, cardiac case group, and 70 patients, control group, without heart disease were retrospectively analyzed. Pre-, and postoperative and at discharge RDW of the cardiac patients were determined. Lengths of hospital and intensive care unit (ICU) stay and exited patients were determined. Results. Mean lengths of ICU and hospital stay were 3.3 ± 2.7 and 7.3 ± 2.9 days. In control group, mean preoperative RDW was 12.6 ± 1.4, while in cardiac case group it was significantly higher (15.1 ± 3.5). In cardiac case group, postoperative RDW were significantly higher than preoperative period, while RDW at discharge were significantly lower than postoperative estimates. A significant and a positive correlation was detected between lengths of ICU and hospital stay and RDW. RDW of the exited patients were significantly higher than the survivors. Conclusions. This study demonstrates that RDW can be used as an important indicator in the prediction of morbidity and mortality during pre-, and postoperative period of the pediatric congenital heart disease surgery.

The relationship between complete blood count parameters and Fontaine's Stages in patients with peripheral arterial disease

OBJECTIVE

The aim of the present study is to evaluate whether blood count parameters differ according to the stages of Fontaine's classification and to investigate the relationship between hemogram parameters and the severity of the disease.

METHOD

Eighty-two peripheral arterial disease patients were examined prospectively. Patients were classified according to the Fontaine classification system. Fifty newly diagnosed patients were included in the study. The neutrophil-to-lymphocyte ratio, mean platelet volume, and red blood cell distribution width values were recorded.

RESULTS

Mean neutrophil-to-lymphocyte ratio values were found to be 3.31 ± 1.1% in Stage I, 3.11 ± 1.3% in Stage II, and 3.48 ± 1.1% in Stage III (p > 0.05). Mean platelet volume values were found to be 7.8 ± 0.6 fl (Stage I), 8.2 ± 1.0 fl (Stage II), and 9.0 ± 0.9 fl (Stage III) (p < 0.05). Red blood cell distribution width values were found to be 13.6 ± 1.0% in Stage I, 14.8 ± 1.7% in Stage II, and 15.4 ± 2.3% in Stage III, being significantly different among all three stages (p < 0.05).

CONCLUSION

Both red blood cell distribution width and mean platelet volume are found to be associated with the severity of atherosclerotic disease in patients with peripheral arterial disease. This finding hypothesizes that complete blood counting parameters may serve as a beneficial and cost-effective method for monitoring atherosclerotic peripheral disease.

Red blood cell distribution width and diabetes-associated complications

AIM

Red blood cell distribution width (RDW) is a marker of cardiovascular morbidity and mortality. However, there is little data on the relationship between RDW and diabetes-associated complications. The aim was to investigate whether there is any association between RDW, nephropathy, neuropathy and peripheral arterial disease (PAD) in a type 2 diabetic population.

METHODS

This study included 196 diabetic patients with proliferative diabetic retinopathy. All subjects were investigated for diabetic nephropathy, diabetic neuropathy and PAD. Participants underwent 24-h blood pressure monitoring and were analysed for markers of the metabolic syndrome, inflammation, and insulin resistance.

RESULTS

57% of the participants had diabetic nephropathy, 46% had diabetic neuropathy while 26% had PAD. No significant association was found between RDW, diabetic neuropathy and PAD (p=NS). However, RDW was strongly associated with diabetic nephropathy (p=0.006), even following adjustment for potential confounding variables. Multivariate logistic regression analysis showed RDW (odds ratio [OR] 1.64, 95% confidence interval [CI] 1.15-2.35, p=0.006), estimated glomerular filtration rate (OR 0.98, 95% CI 0.96-0.99, p<0.001), night-time diastolic blood pressure (OR 1.07, 95% CI 1.03-1.11, p=0.001) and erythrocyte sedimentation rate (OR 1.03, 95% CI 1.004-1.05, p=0.019) to be independently associated with diabetic nephropathy.

CONCLUSIONS

This is the first study to report lack of association between RDW, neuropathy and PAD in subjects with type 2 diabetes mellitus. More importantly, RDW was shown to be significantly associated with diabetic nephropathy in a type 2 diabetic population with advanced proliferative retinopathy independent of traditional risk factors, including diabetes duration and glycaemic control.

Red cell distribution width is associated with long-term prognosis in patients with stable coronary artery disease

Background

Data regarding the association between red cell distribution width (RDW) values and mortality in patients with stable coronary artery disease are scarce. We aimed to investigate the link between mortality and RDW in patients with stable coronary artery disease undergoing percutaneous coronary intervention (PCI).

Methods

We analyzed 2550 consecutive patients with stable coronary artery disease who underwent PCI between 2007 and 2011 at our institution. The patients were divided into four groups according to RDW quartiles. The association between the RDW values and the outcomes was assessed using Cox proportional regression analysis after adjusting for clinical, echocardiographic, hemodynamic and laboratory data in the whole population and in subgroups stratified by gender, presence of diabetes, anemia or heart failure.

Results

In the entire population, there was a stepwise relationship between RDW intervals and comorbidities. Patients with the highest RDW values were older and more often burdened with diabetes, heart failure and chronic kidney disease. There was an almost 4-fold increase in mortality during an average of 2.5 years of follow-up between the group of patients with RDW values lower than 13.1% (25^th percentile) and the group with RDW values higher than 14.1% (75^th percentile), (4.3% vs. 17.1%, p < 0.0001). After adjusting for the covariates, RDW remained significantly associated with mortality in the whole cohort (HR-1.23 [95% CI (1.13-1.35), p < 0.0001]) and in the subgroups stratified by gender, age (over and under 75 years), presence of anemia, diabetes, heart failure and chronic kidney disease.

Conclusion

Higher RDW values correspond to higher comorbidity burdens and higher mortality. RDW is an independent predictor of mortality in patients with stable coronary artery disease.