Red Blood Cell Distribution Width and the Risk of Death in Middle-aged and Older Adults

Abstract

Background Red cell distribution width (RDW), a component of an electronic complete blood count, is a measure of heterogeneity in the size of circulating erythrocytes. In patients with symptomatic cardiovascular disease (CVD), RDW is associated with mortality. However, it has not been demonstrated that RDW is a predictor of mortality independent of nutritional deficiencies or in the general population. Methods RDW was measured in a national sample of 8175 community-dwelling adults aged 45 and older who participated in the 1988–1994 National Health and Nutrition Examination Survey; mortality follow-up occurred through December 31, 2000. Deaths from all causes, CVD, cancer, and other causes were examined as a function of RDW. Results Higher RDW values were strongly associated with an increased risk of death. Compared to the lowest quintile of RDW, the following were adjusted hazard ratios (HR) for all-cause mortality (and 95 percent confidence intervals): second quintile, 1.1 (0.9–1.3); third quintile, 1.2 (1.0–1.4); fourth quintile, 1.4 (1.2–1.8); fifth quintile, 2.1 (1.7–2.6). For every 1 percent increment in RDW, all-cause mortality risk increased by 22% [HR = 1.22 (1.15–1.30); p<0.001]. Even when analyses were restricted to non-anemic participants or to those in the normal range of RDW (11–15%) without iron, folate, or vitamin B12 deficiency, RDW remained strongly associated with mortality. The prognostic effect of RDW was observed in both middle-aged and older adults for multiple causes of death. Conclusions RDW is a widely-available test that is a strong predictor of mortality in the general population of adults aged 45 and older.

Association between red blood cell distribution width and macrovascular and microvascular complications in diabetes

“…Although higher RDW levels have been related to cardiovascular morbidity and mortality in several study populations [4][5][6][7], RDW has not been studied as a marker of complications in diabetes. In the present investigation, we used the NHANES III database to demonstrate a relationship between RDW and CVD in a selected diabetes population that is representative of approximately 18 million USA adults aged 20 years and older.…”

“…Thus it is possible that microvascular disease and the related inflammatory process of retinopathy may occur mostly at the local tissue level and not be related to systemic inflammation [18,26]. Since RDW seems to reflect systemic inflammatory processes known to affect the macrovasculature [6,24], this may explain, at least partially, its relationship with macrovascular but not microvascular disease processes. Previous prospective studies have described a role of RDW as a predictive marker for CVD morbidity and mortality in several populations [4][5][6][7].…”

“…Folate and vitamin B 12 deficiencies were defined by erythrocyte folate levels <232.49 nmol/l and serum vitamin B 12 levels <147.6 pmol/l, respectively [6].…”

“…RDW levels, even within the normal range, have been strongly and independently associated with risk of all-cause and cardiovascular mortality in patients with CVD [4,5] and in the general population [6,7]. RDW has also been related to increased risk of new cardiovascular events in people with previous myocardial infarction [5].…”

Red Cell Distribution Width as a Predictor of Prostate Cancer Progression

“…Some previous studies and a meta-analysis demonstrated that RDW is a potent predictor of all-cause mortality, including cancer-related deaths (Patel et al, 2009;Perlstein et al, 2009;Patel et al, 2010). There is also a strong, graded association between RDW and inflammatory biomarkers (fibrinogen, serum C-reactive protein [CRP], and erythrocyte sedimentation rate [ESR]), which is independent of numerous confounding factors (Cakal et al, 2009;Lippi et al, 2009).…”