Red cell distribution width and mortality in newly hospitalized patients

Association of red blood cell distribution width with hospital admission and in-hospital mortality across all-cause adult emergency department visits

Objectives

To test the association between the initial red blood cell distribution width (RDW) value in the emergency department (ED) and hospital admission and, among those admitted, in-hospital mortality.

Materials and Methods

We perform a retrospective analysis of 210 930 adult ED visits with complete blood count results from March 2013 to February 2022. Primary outcomes were hospital admission and in-hospital mortality. Variables for each visit included demographics, comorbidities, vital signs, basic metabolic panel, complete blood count, and final diagnosis. The association of each outcome with the initial RDW value was calculated across 3 age groups (<45, 45-65, and >65) as well as across 374 diagnosis categories. Logistic regression (LR) and XGBoost models using all variables excluding final diagnoses were built to test whether RDW was a highly weighted and informative predictor for each outcome. Finally, simplified models using only age, sex, and vital signs were built to test whether RDW had additive predictive value.

Results

Compared to that of discharged visits (mean [SD]: 13.8 [2.03]), RDW was significantly elevated in visits that resulted in admission (15.1 [2.72]) and, among admissions, those resulting in intensive care unit stay (15.3 [2.88]) and/or death (16.8 [3.25]). This relationship held across age groups as well as across various diagnosis categories. An RDW >16 achieved 90% specificity for hospital admission, while an RDW >18.5 achieved 90% specificity for in-hospital mortality. LR achieved a test area under the curve (AUC) of 0.77 (95% confidence interval [CI] 0.77-0.78) for hospital admission and 0.85 (95% CI 0.81-0.88) for in-hospital mortality, while XGBoost achieved a test AUC of 0.90 (95% CI 0.89-0.90) for hospital admission and 0.96 (95% CI 0.94-0.97) for in-hospital mortality. RDW had high scaled weights and information gain for both outcomes and had additive value in simplified models predicting hospital admission.

Discussion

Elevated RDW, previously associated with mortality in myocardial infarction, pulmonary embolism, heart failure, sepsis, and COVID-19, is associated with hospital admission and in-hospital mortality across all-cause adult ED visits. Used alone, elevated RDW may be a specific, but not sensitive, test for both outcomes, with multivariate LR and XGBoost models showing significantly improved test characteristics.

Conclusions

RDW, a component of the complete blood count panel routinely ordered as the initial workup for the undifferentiated patient, may be a generalizable biomarker for acuity in the ED.

Red cell distribution width and mortality in older patients with frailty in the emergency department

BACKGROUND

The red cell distribution width (RDW) reflects the degree of heterogeneity of red blood cells. Elevated RDW is associated both with frailty and with increased mortality in hospital-admitted patients. In this study we evaluate whether high RDW values are associated with mortality in older emergency department (ED) patients with frailty, and if the association is independent of the degree of frailty.

METHODS

We included ED patients with the following criteria: ≥ 75 years of age, Clinical Frailty Scale (CFS) score of 4 to 8, and RDW % measured within 48 h of ED admission. Patients were allocated to six classes by their RDW value: ≤ 13%, 14%, 15%, 16%, 17%, and ≥ 18%. The outcome was death within 30 days of ED admission. Crude and adjusted odds ratios (OR) with 95% confidence intervals (CI) for a one-class increase in RDW for 30-day mortality were calculated via binary logistic regression analysis. Age, gender and CFS score were considered as potential confounders.

RESULTS

A total of 1407 patients (61.2% female), were included. The median age was 85 with an inter-quartile range (IQR) of 80-89, median CFS score 6 (IQR: 5-7), and median RDW 14 (IQR: 13-16). Of the included patients, 71.9% were admitted to hospital wards. A total of 85 patients (6.0%) died during the 30-day follow-up. Mortality rate was associated with RDW increase (p for trend < .001). Crude OR for a one-class increase in RDW for 30-day mortality was 1.32 (95% CI: 1.17-1.50, p < .001). When adjusted for age, gender and CFS-score, OR of mortality for one-class RDW increase was still 1.32 (95% CI: 1.16-1.50, p < .001).

CONCLUSION

Higher RDW values had a significant association with increased 30-day mortality risk in frail older adults in the ED, and this risk was independent of degree of frailty. RDW is a readily available biomarker for most ED patients. It might be beneficial to include it in risk stratification of older frail ED patients to identify those who could benefit from further diagnostic assessment, targeted interventions, and care planning.

A study of elevated red cell distribution width (RDW) in early-onset neonatal sepsis

Background

Neonatal sepsis is a serious infection occurring within the first 28 days of life. It is a significant cause of mortality and morbidity. Red cell distribution width (RDW) is estimated within the standard CBC profile and considered a simple tool for the diagnosis of neonatal sepsis without additional cost. Our aim in this study is to investigate the potential role of red cell distribution width (RDW) in the diagnosis of early-onset neonatal sepsis (EONS). The aim of our study is to detect the role of red cell distribution width (RDW) in the diagnosis and prognosis of early-onset neonatal sepsis (EONS).

Results

This case-control study was conducted at the NICU of Beni-Suef University Hospital and revealed that RDW% was highly significantly higher among cases than among controls (16.65 ± 4.28, 11.13 ± 0.62, respectively); regarding the severity of neonatal sepsis, we divided our cases into three groups (sepsis group includes 21 neonates, severe sepsis group includes 31 neonates, and septic shock group includes 48 neonates), there were statistically significant differences between the three groups (sepsis, severe sepsis, and septic shock) regarding RDW (15.15 ± 1.65, 16.78 ± 2.01, 17.02 ± 2.02, respectively) as P value (0.027).

Conclusion

This study revealed that RDW is associated with the diagnosis and prognosis of early-onset neonatal sepsis, so further study is needed to prove causation as it is being simple, less expensive, available, and easily repeated as it is routinely done with CBC, so it will be a good indicator for prognosis of neonatal sepsis.

Red cell distribution width, illness severity, and all-cause mortality in dogs admitted to the ICU

OBJECTIVE

To determine whether red cell distribution width (RDW) can predict illness severity and mortality risk in a heterogenous population of dogs admitted to the ICU.

DESIGN

Prospective observational study.

SETTING

Large, urban, private teaching hospital.

ANIMALS

One hundred eleven dogs consecutively admitted to the ICU between September 2017 and December 2018.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Abbreviated Acute Patient Physiologic and Laboratory Evaluation (APPLE_fast ) score and RDW were measured within 6 h of ICU admission. This study did not demonstrate a significant difference in illness severity across patients stratified by RDW. There was no difference in RDW between survivors and nonsurvivors at hospital discharge or at 30 days.

CONCLUSIONS

In this study population, RDW did not correspond with illness severity as measured by APPLE_fast . Moreover, RDW did not predict in-hospital or 30-day mortality.

Association Between Variation in Red Cell Size and Multiple Aging-Related Outcomes

BACKGROUND

We tested whether greater variation in red blood cell size, measured by red cell distribution width (RDW), may predict aging-related degenerative conditions and therefore, serve as a marker of biological aging.

METHODS

Three thousand six hundred and thirty-five community-dwelling older men were enrolled in the prospective Osteoporotic Fractures in Men Study. RDW was categorized into 4 groups (≤13.0%, 13.1%-14.0%, 14.1%-15.0%, and ≥15.1%). Functional limitations, frailty, strength, physical performance, and cognitive function were measured at baseline and 7.4 years later. Falls were recorded in the year after baseline; hospitalizations were obtained for 2 years after baseline. Mortality was assessed during a mean of 8.3 years of follow-up.

RESULTS

Participants with greater variability in red cell size were weaker, walked more slowly, and had a worse cognitive function. They were more likely to have functional limitations (35.2% in the highest RDW category vs 16.0% in the lowest, p < .001) and frailty (30.3% vs 11.3%, p < .001). Those with greater variability in red cell size were more likely to develop new functional limitations and to become frail. The risk of having 2 or more falls was also greater (highest 19.2% vs lowest 10.3%, p < .001). The risk of hospitalization was higher in those with the highest variability (odds ratio [95% confidence interval], 1.8 [1.3-2.5]) compared with the lowest. Variability in red cell size was related to total and cause-specific mortality.

CONCLUSION

Greater variability in red cell size is associated with diverse aging-related outcomes, suggesting that it may have potential value as a marker for biological aging.

Red Cell Distribution Width Is a Risk Factor for Hip Fracture in Elderly Men Without Anemia

Red cell distribution width (RDW), routinely assessed as a component of a complete blood count (CBC), quantifies the variation in the size of red blood cells. It increases with age, and increased RDW predicts many aging-related diseases and mortality. However, whether it also predicts hip fracture is unknown. We prospectively evaluated the association between RDW and hip fracture using data from the Osteoporotic Fracture in Men (MrOS) study. RDW was measured in 3635 men (aged 71 to 99 years) along with bone mineral density (BMD) in MrOS. RDW ranged from 11.3% to 32.9% (median 14.0%; interquartile range 13.5% to 14.8%) and was categorized into four groups (≤13.0%, 13.1% to 14.0%, 14.1% to 15.0%, ≥15.1%). Study participants with a hemoglobin level <13.0 g/dL were classified as having anemia. During an average 8.1 years, 164 men suffered hip fractures. The risks of hip fractures increased with increase of RDW category. Furthermore, there was a significant interaction between anemia and RDW: An association between RDW and hip fractures was only observed in participants without anemia. In those without anemia, the relative hazard of hip fractures increased with increases in RDW category: Men in the highest RDW category had a 2.8 times higher risk of hip fractures than men in the lowest group (95% confidence interval 1.1 to 7.1). The risks of all-clinical fractures were also increased along with higher RDW values. Additionally, RDW was significantly associated with the risk of having a fall but not with femoral neck or total hip BMD. In conclusion, RDW and anemia defined by hemoglobin are widely available routine laboratory measurements that together could indicate increased risk of hip fracture, reflecting the neuromuscular effects of aging rather than lower hip BMD. © 2020 American Society for Bone and Mineral Research.

min-SIA: a Lightweight Algorithm to Predict the Risk of 6-Month Mortality at the Time of Hospital Admission

BACKGROUND

Predicting death in a cohort of clinically diverse, multi-condition hospitalized patients is difficult. This frequently hinders timely serious illness care conversations. Prognostic models that can determine 6-month death risk at the time of hospital admission can improve access to serious illness care conversations.

OBJECTIVE

The objective is to determine if the demographic, vital sign, and laboratory data from the first 48 h of a hospitalization can be used to accurately quantify 6-month mortality risk.

DESIGN

This is a retrospective study using electronic medical record data linked with the state death registry.

PARTICIPANTS

Participants were 158,323 hospitalized patients within a 6-hospital network over a 6-year period.

MAIN MEASURES

Main measures are the following: the first set of vital signs, complete blood count, basic and complete metabolic panel, serum lactate, pro-BNP, troponin-I, INR, aPTT, demographic information, and associated ICD codes. The outcome of interest was death within 6 months.

KEY RESULTS

Model performance was measured on the validation dataset. A random forest model-mini serious illness algorithm-used 8 variables from the initial 48 h of hospitalization and predicted death within 6 months with an AUC of 0.92 (0.91-0.93). Red cell distribution width was the most important prognostic variable. min-SIA (mini serious illness algorithm) was very well calibrated and estimated the probability of death to within 10% of the actual value. The discriminative ability of the min-SIA was significantly better than historical estimates of clinician performance.

CONCLUSION

min-SIA algorithm can identify patients at high risk of 6-month mortality at the time of hospital admission. It can be used to improved access to timely, serious illness care conversations in high-risk patients.

Patient centred variables with univariate associations with unplanned ICU admission: a systematic review

Background

Multiple predictive scores using Electronic Patient Record data have been developed for hospitalised patients at risk of clinical deterioration. Methods used to select patient centred variables for inclusion in these scores varies. We performed a systematic review to describe univariate associations with unplanned Intensive Care Unit (ICU) admission with the aim of assisting model development for future scores that predict clinical deterioration.

Methods

Data sources were MEDLINE, EMBASE, CINAHL, CENTRAL and the Cochrane Database of Systematic Reviews. Included studies were published since 2000 describing an association between patient centred variables and unplanned ICU admission determined using univariate analysis. Two authors independently screened titles, abstracts and full texts against inclusion and exclusion criteria. DistillerSR (Evidence Partners, Canada, Ottawa, Ontario) software was used to manage the data and identify duplicate search results. All screening and data extraction forms were implemented within DistillerSR. Study quality was assessed using an adapted version of the Newcastle-Ottawa Scale. Variables were analysed for strength of association with unplanned ICU admission.

Results

The database search yielded 1520 unique studies; 1462 were removed after title and abstract review; 57 underwent full text screening; 16 studies were included. One hundred and eighty nine variables with an evaluated univariate association with unplanned ICU admission were described.

Discussion

Being male, increasing age, a history of congestive cardiac failure or diabetes, a diagnosis of hepatic disease or having abnormal vital signs were all strongly associated with ICU admission.

Conclusion

These findings will assist variable selection during the development of future models predicting unplanned ICU admission.

Trial registration

This study is a component of a larger body of work registered in the ISRCTN registry (ISRCTN12518261).

Electronic supplementary material

The online version of this article (10.1186/s12911-019-0820-1) contains supplementary material, which is available to authorized users.

Relationship of Red Cell Distribution Width to Adverse Outcomes in Adults With Congenital Heart Disease (from the Boston Adult Congenital Heart Biobank)

Red cell distribution width (RDW), a measure of variability in red cell size, predicts adverse outcomes in acquired causes of heart failure. We examined the relation of RDW and outcomes in adults with congenital heart disease. We performed a prospective cohort study on 696 ambulatory patients ≥18years old enrolled in the Boston Adult Congenital Heart Disease Biobank between 2012 and 2016 (mean age 38.7 ± 13.5 years; 49.9% women). The combined outcome was all-cause mortality or nonelective cardiovascular hospitalization. Most patients had moderately or severely complex congenital heart disease (42.5% and 38.5%, respectively). Mean RDW was 14.0 ± 1.3%. RDW >15% was present in 81 patients (11.6%). After median 767days of follow-up, 115 patients sustained the primary combined outcome, including 31 who died. Higher RDW predicted both the combined outcome (hazard ratio [HR] for RDW >15% = 4.5, 95% confidence interval [CI] 3.0 to 6.6; HR per + 1SD RDW = 1.8, 95% CI 1.6 to 2.0, both p <0.0001) and death alone (HR for RDW >15% = 7.1, 95% CI 3.5 to 14.4; HR per + 1SD RDW = 1.8, 95% CI 1.6 to 2.0, both p <0.0001). RDW remained an independent predictor of the combined outcome after adjusting for age, cyanosis, congenital heart disease complexity, ventricular systolic function, New York Heart Association functional class, hemoglobin concentration, mean corpuscular volume, high-sensitivity C-reactive protein and estimated glomerular filtration rate (HR per + 1SD RDW = 1.5, 95% CI 1.2 to 1.9, p <0.0001). RDW also remained an independent predictor of mortality alone after adjustment for age plus each variable individually. In conclusion, elevated RDW is an independent predictor of all-cause mortality or nonelective cardiovascular hospitalization in adults with congenital heart disease. This simple clinical biomarker identifies increased risk for adverse events even among patients with preserved functional status.

Biological pathways underlying the association of red cell distribution width and adverse clinical outcome: Results of a prospective cohort study

Background

Red cell distribution width (RDW) predicts disease outcome in several patient populations, but its prognostic value in addition to other disease parameters in unselected medical inpatients remains unclear. Our aim was to investigate the association of admission RDW levels and mortality adjusted for several disease pathways in unselected medical patients from a previous multicenter study.

Methods

We included consecutive adult, medical patients at the time point of hospital admission through the emergency department into this observational, cohort study. The primary endpoint was mortality at 30-day. To study association of admission RDW and outcomes, we calculated regression analysis with step-wise inclusion of clinical and laboratory parameters from different biological pathways.

Results

The 30-day mortality of the 4273 included patients was 5.6% and increased from 1.4% to 14.3% from the lowest to the highest RDW quartile. There was a strong association of RDW and mortality in unadjusted analysis (OR 1.32; 95%CI 1.27–1.39, p<0.001). RDW was strongly correlated with different pathways including inflammation (coefficient of determination (R²) 0.30; p<0.001), nutrition (R² 0.20; p<0.001) and blood diseases (R² 0.30; p<0.001 The association was eliminated after including different biological pathways into the models with the fully adjusted regression model showing an OR of 1.02 (95%CI 0.93–1.12; p = 0.664) for the association of RDW and mortality. Similar effects were found for other outcomes including intensive care unit admission and hospital readmission.

Conclusion

Our data suggests that RDW is a strong surrogate marker of mortality in unselected medical inpatients with most of the prognostic information being explained by other disease factors. The strong correlation of RDW and different biological pathways such as chronic inflammation, malnutrition and blood disease suggest that RDW may be viewed as an unspecific and general “chronic disease prognostic marker”.

Vitamin D Status and Elevated Red Cell Distribution Width in Community-Dwelling Adults: Results from the National Health and Nutrition Examination Survey 2001-2006

OBJECTIVES

Elevated red cell distribution width (RDW) is associated with morbidity and mortality in community-dwelling individuals. Although RDW is traditionally used to diagnose anemia, it may also be a marker of systemic inflammation. Since vitamin D is a potent modulator of inflammatory cytokines our goal was to investigate whether 25-hydroxyvitamin D levels (25OHD) are associated with RDW in non-hospitalized adults.

DESIGN

To investigate this association, we conducted a cross-sectional study. Stepwise multivariable linear and logistic regression models were used to assess the independent association of 25OHD with RDW. Elevated RDW was defined as >14.5%.

SETTING

Nationwide sample of non-hospitalized adults within the United States.

PARTICIPANTS

Individuals from the National Health and Nutrition Examination Survey from 2001-2006.

RESULTS

15,162 individuals comprised the analytic cohort. Mean 25OHD was 24.9 ng/mL (SE 0.4) and the prevalence of elevated RDW was 6.3%. Linear regression analysis, controlling for age, sex, race, mean corpuscular volume, albumin, and neutropenia, demonstrated that 25OHD was inversely associated with RDW (β=-0.01; 95%CI -0.01 to -0.01). Logistic regression analysis, controlling for the same covariates, also demonstrated an inverse association of 25OHD with elevated RDW (OR 0.96; 95%CI 0.94-0.99). Individuals with 25OHD <30 ng/mL were more likely to have elevated RDW (OR 1.65; 95%CI 1.13-2.40) compared to those individuals with levels ≥30ng/mL.

CONCLUSIONS

In a nationwide sample of non-hospitalized adults within the United States, low 25OHD was associated with increased likelihood of elevated RDW. Further studies are needed to determine whether optimizing vitamin D status can reduce the prevalence of elevated RDW, and thereby reduce morbidity and mortality in the general population.

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.

Changes in Red Cell Distribution Width During Hospitalization for Community-Acquired Pneumonia: Clinical Characteristics and Prognostic Significance

PURPOSE

We investigated outcomes of patients hospitalized with community-acquired pneumonia (CAP) according to the changes in red cell distribution width (RDW).

METHODS

For 980 adults, clinical characteristics, outcomes during hospitalization for CAP (transfer to the intensive care unit, treatment with mechanical ventilation, prolonged hospital stay, and death), and all-cause mortality following discharge were compared: according to RDW changes versus stable RDW during hospitalization, and according to normal (≤14.7 %) versus high (>14.7 %) RDW values on admission/discharge.

RESULTS

RDW changes (n = 386) during hospitalization were associated with more severe clinical and laboratory characteristics than stable RDW (n = 594). Changes in RDW strongly predicted poor in-hospital outcomes (p < 0.001). The respective 30, 90-day, and total (median follow-up 54 months) mortality rates were significantly higher (9.8, 16.0 and 43.5 %) among patients with RDW changes, compared to 4.0, 7.6 and 30.5 % among those with stable RDW (p < 0.001 for all comparisons). RDW changes, as well as high RDW (each 1 % increment) on admission and discharge, were powerful predictors of mortality (the respective relative risks 1.41, 1.13, and 1.15, and 95 % confidence intervals 1.13-1.74, 1.08-1.19, and 1.10-1.21).

CONCLUSIONS

RDW changes during hospitalization for CAP are common and associated with a severe clinical profile. Time-dependent RDW changes strongly predict poor in-hospital outcomes and increased short- and long-term mortality. Repeated RDW determinations during hospitalization for CAP may provide useful prognostic information.

Elevated Red Cell Distribution Width Is Associated With Decreased Ventilator-Free Days in Critically Ill Patients

INTRODUCTION

Elevated red cell distribution width (RDW) is associated with mortality in a variety of respiratory conditions. Recent data also suggest that RDW is associated with mortality in intensive care unit (ICU) patients. Although respiratory failure is common in the ICU, the relationship between RDW and pulmonary outcomes in the ICU has not been previously explored. Therefore, our goal was to investigate the association of admission RDW with 30-day ventilator-free days (VFDs) in ICU patients.

METHODS

We performed a retrospective analysis from an ongoing prospective, observational study. Patients were recruited from medical and surgical ICUs of a large teaching hospital in Boston, Massachusetts. The RDW was assessed within 1 hour of ICU admission. Poisson regression analysis was used to investigate the association of RDW (normal: 11.5%-14.5% vs elevated: >14.5%) with 30-day VFD, while controlling for age, sex, race, body mass index, Nutrition Risk in the Critically Ill score, the presence of chronic lung disease, Pao₂/Fio₂ ratio, and admission levels of hemoglobin, mean corpuscular volume, phosphate, albumin, C-reactive protein, and creatinine.

RESULTS

A total of 637 patients comprised the analytic cohort. Mean RDW was 15 (standard deviation 4%), with 53% of patients in the normal range and 47% with elevated levels. Median VFD was 16 (interquartile range: 6-25) days. Poisson regression analysis demonstrated that ICU patients with elevated admission RDW were likely to have 32% lower 30-day VFDs compared to their counterparts with RDW in the normal range (incidence rate ratio: 0.68; 95% confidence interval: 0.55-0.83: P < .001).

CONCLUSIONS

We observed an inverse association of RDW and 30-day VFD, despite controlling for demographics, nutritional factors, and severity of illness. This supports the need for future studies to validate our findings, understand the physiologic processes that lead to elevated RDW in patients with respiratory failure, and determine whether changes in RDW may be used to support clinical decision-making.

Prognostic significance of changes in red cell distribution width in an internal medicine ward

BACKGROUND

The prognostic significance of red cell distribution width (RDW) during hospitalization in internal medicine wards was not sufficiently investigated.

METHODS

Demographic, clinical and laboratory characteristics were collected from 586 internal medicine inpatients. Following discharge, all-cause mortality was recorded. The data were compared according to ΔRDW during hospitalization (primary endpoint), and to normal (≤14.7%) vs. high (>14.7%) RDW values on admission/discharge (secondary endpoint).

RESULTS

Group A (rise in RDW, ΔRDW +0.4%), group B (nonsignificant RDW changes, ΔRDW up to 0.4%) and group C (drop in RDW, ΔRDW -0.4%) comprised 20.3%, 60.6% and 19.1% of the patients, respectively. High RDW on admission and discharge was found in 31.7% and 31.4% of patients, respectively. In-hospital mortality rates were higher in group A than in groups B and C (14.3% vs. 2.8% and 4.5%, p<0.001), whereas increased long-term (median follow-up 43 months) mortality rates were observed in group C (35.7%), compared to groups A (17.6%) and B (23.4%), p=0.009. Mortality rates were significantly higher (p<0.001) in patients with high than normal RDW on admission (51.1% vs. 20.3%) and on discharge (50.5% vs. 20.6%). Every 1% increment of RDW on admission and discharge strongly predicted mortality (relative risks 1.21 and 1.21; 95% confidence intervals 1.12-1.31 and 1.13-1.32, respectively).

CONCLUSIONS

High RDW on admission and discharge predicted poor prognosis. Rising RDW throughout hospitalization was associated with higher in-hospital mortality, while an elevated long-term mortality rate was observed in patients with declining RDW. Repeated RDW measurements may improve risk stratification for internal medicine inpatients.

The early detection of anaemia and aetiology prediction through the modelling of red cell distribution width (RDW) in cross-sectional community patient data

Red cell distribution width (RDW) is a marker of iron-deficient anaemia that can also assist differentiation of other anaemias. RDW also has been suggested as an effective marker for earlier anaemia detection. The RDW-anaemia relationship was investigated in cross-sectional community patient data, and the capacity of RDW to predict the diagnostic value of second tier anaemia markers assessed.

Routine and second tier assay data were provided by the laboratory Sullivan Nicolaides Pathology. The cohort was divided into male and female groups stratified by age, and correlation analyses assessed associations of RDW to haemoglobin and ferritin. Analysis of covariance (ANCOVA) was performed for both routine and second tier markers to investigate their significance for RDW prediction.

RDW had statistically significant negative correlation with haemoglobin for both sexes and age ranges (p<0.01). The RDW relationship with serum ferritin was non-linear, representing two populations. ANCOVA showed categorical ferritin as a significant RDW predictor for younger females, with vitamin B12 a significant RDW predictor for older men. Haemoglobin, mean corpuscular haemoglobin (MCH) and second tier iron markers (e.g., transferrin) were significant RDW predictors for both sexes and ages investigated. An individual longitudinal female case study showed RDW as very sensitive to haemoglobin decrease, with ferritin not as responsive.

RDW had a significant negative association with haemoglobin in cross-sectional community patient data. ANCOVA showed ferritin as a significant RDW predictor for younger females only. This study confirms the utility of RDW as a marker for early anaemia detection, and useful to accelerated diagnoses of anaemia aetiology.

Change in Red Blood Cell Distribution width During the Last Years of Life in Geriatric Patients

OBJECTIVES

Most of the studies that evaluate the association between red blood cell distribution width (RDW) and mortality assess it on a single occasion instead of doing so through serial measurements. Very few studies have investigated repeated measurements of RDW and its prognostic value, and most of them are focused on patients with cardiovascular diseases. RDW is a dynamic value so we aimed at determining the prognostic value of sequential RDW assessment in the last years of life in patients enrolled in a Department of Geriatrics.

DESIGN

This work is part of a prospective study derived from a cohort of 122 patients over 75 years hospitalized in 2005 for the purpose of assessing the prognostic significance of several comorbidity and prognostic indices.

SETTING

Patients were consecutively recruited for the study at admission in a tertiary hospital and then followed up for at least 5 years.

PARTICIPANTS

A total of 55 patients with repeated RDW assessments during all the five years before their death were selected from the total cohort of 122 patients.

RESULTS

We found a strong correlation between progressive rise in RDW and mortality risk, especially during the last year of life. There was a gradual significant increase in the RDW values along the last five years of life, with means growing up from 14,8 (95% CI: 13,98-15.62) to 16,37 (15,80-16,94).

CONCLUSION

In our cohort of geriatric patients, RDW is a dynamic variable that is modified during the last five years of life, irrespective of their age, and especially during the last year.

Does the addition of RDW improve current ICU scoring systems?

BACKGROUND

The aim of this study was to evaluate whether the addition of red blood cell distribution width (RDW) improves the prognostic value of current intensive care unit (ICU) scoring systems, namely APACHE III.

DESIGN AND METHODS

All patients admitted to a mixed ICU in Brisbane between June 2013 and July 2014 for whom RDW was available were included in the study. Analyses included descriptive statistics, linear regression correlation, and receiver operating characteristic (ROC) curves.

RESULTS

The study included 708 patients for whom both ICU mortality prediction and RDW were available. In univariate analysis higher RDW values were associated with increased hospital mortality. Adding RDW to APACHE III increased the area under the ROC marginally (from 0.9586 to 0.9613). RDW was not correlated with C-reactive protein, white cell count, or patient's length of stay in ICU.

CONCLUSION

RDW was an independent predictor of mortality. The addition of RDW to APACHE III improved its mortality prediction marginally. The underlying mechanism of RDW elevation warrants further investigation.

Red cell distribution width improves the simplified acute physiology score for risk prediction in unselected critically ill patients

Introduction

Recently, red cell distribution width (RDW), a measure of erythrocyte size variability, has been shown to be a prognostic marker in critical illness. The aim of this study was to investigate whether adding RDW has the potential to improve the prognostic performance of the simplified acute physiology score (SAPS) to predict short- and long-term mortality in an independent, large, and unselected population of intensive care unit (ICU) patients.

Methods

This observational cohort study includes 17,922 ICU patients with available RDW measurements from different types of ICUs. We modeled the association between RDW and mortality by using multivariable logistic regression, adjusting for demographic factors, comorbidities, hematocrit, and severity of illness by using the SAPS.

Results

ICU-, in-hospital-, and 1-year mortality rates in the 17,922 included patients were 7.6% (95% CI, 7.2 to 8.0), 11.2% (95% CI, 10.8 to 11.7), and 25.4% (95% CI, 24.8 to 26.1). RDW was significantly associated with in-hospital mortality (OR per 1% increase in RDW (95%CI)) (1.14 (1.08 to 1.19), P < 0.0001), ICU mortality (1.10 (1.06 to 1.15), P < 0.0001), and 1-year mortality (1.20 (95% CI, 1.14 to 1.26); P < 0.001). Adding RDW to SAPS significantly improved the AUC from 0.746 to 0.774 (P < 0.001) for in-hospital mortality and 0.793 to 0.805 (P < 0.001) for ICU mortality. Significant improvements in classification of SAPS were confirmed in reclassification analyses. Subgroups demonstrated robust results for gender, age categories, SAPS categories, anemia, hematocrit categories, and renal failure.

Conclusions

RDW is a promising independent short- and long-term prognostic marker in ICU patients and significantly improves risk stratification of SAPS. Further research is needed the better to understand the pathophysiology underlying these effects.