Vitamin D status and elevated red cell distribution width in community-dwelling adults: Results from the National Health and Nutrition Examination Survey 2001’2006
The journal of nutrition, health & aging First Online: 07 October 2017
T. M. N. OteroD. J. MonlezunK. B. ChristopherC. A. CamargoSadeq A. Quraishi
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.
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.
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.
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.
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Clin Biochem. 2015 Nov;48(16-17):1048-52. doi: 10.1016/j.clinbiochem.2015.07.011. Epub 2015 Jul 10.
Fujita B1, Franz M2, Figulla HR2, Pfeifer R2, Kabisch B2, Fritzenwanger M2, Jung C2.
Red cell distribution width was shown to reliably predict mortality and morbidity in numerous clinical settings, including patients hospitalized on surgical intensive care units (ICU). Patients hospitalized on an ICU usually comprise a very heterogeneous patient population. The aim of this analysis was to investigate whether (1) RDW is related to survival outcomes in patients hospitalized on a medical ICU and (2) the prognostic value of RDW is dependent on the diagnosis that led to ICU admission.
829 patients hospitalized on the medical ICU of a tertiary care hospital were retrospectively investigated. Patients were divided in two groups according to the main diagnosis that led to ICU admission. Group 1: non-infectious cardiac disease and group 2: other. The prognostic value of RDW for ICU- and long-term mortality was investigated for the entire patient cohort as well as for the two subgroups.
The median RDW of the whole study population was 16.1%. Patients with an RDW above this threshold were exposed to an increased risk for ICU mortality (34.4% vs. 17.2%, p<0.001) and long-term mortality (log-rank p<0.001). Similarly, this cut-off was able to distinguish patients with an elevated risk for death in subgroup 2 (ICU mortality: 37.9% vs. 19.2%, p<0.001; long-term mortality: log-rank p<0.001). In subgroup 1, this value was not able to identify patients with an increased risk for ICU-mortality (17.6% vs. 11.8%, p=0.26) as well as long-term mortality (log-rank p=0.3).
Data of this analysis revealed that (1) RDW is a powerful predictor for ICU- and long-term mortality in patients hospitalized on a medical ICU and (2) RDW cut-offs to assess risk for death differ according to the main diagnosis that led to ICU admission.
PMID: 26169241 DOI: 10.1016/j.clinbiochem.2015.07.011
Crit Care Med. 2011 Aug; 39(8): 1913–1921, doi: 10.1097/CCM.0b013e31821b85c6, PMCID: PMC4427349
Heidi S. Bazick, MD, Domingo Chang, MD, Karthik Mahadevappa, MBBS, Fiona K. Gibbons, MD, and Kenneth B. Christopher, MD, FASN, FCCP
Red Cell Distribution Width (RDW) is a predictor of mortality in the general population. The prevalence of increased RDW and its significance in the intensive care unit are unknown.
Objective: To investigate the association between RDW at the initiation of critical care and all cause mortality
Design: Multicenter observational study
Setting:Two tertiary academic hospitals in Boston, Massachusetts
Patients: 51,413 patients, age ≥ 18 years, who received critical care between 1997 and 2007
The exposure of interest was RDW and categorized a priori in quintiles as ≤13.3%, 13.3–14.0%, 14.0–14.7%, 14.7–15.8%, and >15.8%. Logistic regression examined death by days 30, 90 and 365 post-critical care initiation, in-hospital mortality and bloodstream infection. Adjusted odds ratios were estimated by multivariable logistic regression models. Adjustment included age, sex, race, Deyo-Charlson index, CABG, MI, CHF, hematocrit, WBC, MCV, BUN, red blood cell transfusion, sepsis and creatinine.
RDW was a particularly strong predictor of all cause mortality 30 days following critical care initiation with a significant risk gradient across RDW quintiles following multivariable adjustment: RDW 13.3–14.0% OR 1.19 (95% CI, 1.08–1.30; P<0.001); RDW 14.0–14.7% OR 1.28 (95% CI, 1.16–1.42; P<0.001); RDW 14.7–15.8% OR 1.69 (95% CI, 1.52–1.86; P<0.001); RDW > 15.8% OR 2.61 (95% CI, 2.37–2.86; P<0.001); all relative to patients with RDW ≤13.3%. Similar significant robust associations post multivariable adjustments are seen with death by days 90 and 365 post-critical care initiation as well as in-hospital mortality. In a sub-analysis of patients with blood cultures drawn (n= 18,525), RDW at critical care initiation was associated with the risk of bloodstream infection and remained significant following multivariable adjustment. The adjusted risk of bloodstream infection was 1.40- and 1.44-fold higher in patients with RDW values in the 14.7–15.8% and >15.8% quintiles, respectively, compared with those with RDW ≤13.3%. Estimating the ROC AUC shows that RDW has moderate discriminative power for 30-day mortality (AUC = 0.67).
RDW is a robust predictor of the risk of all cause patient mortality and bloodstream infection in the critically ill. RDW is commonly measured, inexpensive and widely available and may reflect overall inflammation, oxidative stress, or arterial underfilling in the critically ill.