The Journals of Gerontology Series A: Biological Sciences and Medical Sciences Advance Access published online on October 30, 2009
The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, doi:10.1093/gerona/glp163
Published by Oxford University Press on behalf of The Gerontological Society of America 2009.
Red Cell Distribution Width and Mortality in Older Adults: A Meta-analysis
1 Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Bethesda, Maryland
2 Johns Hopkins University School of Medicine, Baltimore, Maryland
3 Clinical Research Branch, National Institute on Aging, Baltimore, Maryland
4 Departments of Epidemiology and Medicine, University of Pittsburgh, Pennsylvania
5 Mailman School of Public Health, Columbia University, New York, New York
6 Department of Epidemiology, University of Iowa, Iowa City
7 Geriatric Unit, Azienda Sanitaria Firenze, Florence, Italy
8 Deparment of Preventive Medicine, University of Tennessee, Memphis
9 Veterans Affairs Medical Center and Department of Medicine, University of California, San Francisco
10 Departments of Epidemiology and Medicine, Johns Hopkins University, Baltimore, Maryland
Address correspondence to Kushang V. Patel, PhD, National Institute on Aging, 7201 Wisconsin Avenue, Gateway Building, Suite 3C309, Bethesda, MD 20892-9205. Email: kushang.patel{at}nih.gov
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Abstract |
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Background: Red cell distribution width (RDW) is a quantitative measure of variability in the size of circulating erythrocytes with higher values reflecting greater heterogeneity in cell sizes. Recent studies have shown that higher RDW is associated with increased mortality risk in patients with clinically significant cardiovascular disease (CVD). Whether RDW is prognostic in more representative community-based populations is unclear.
Methods: Seven relevant community-based studies of older adults with RDW measurement and mortality ascertainment were identified. Cox proportional hazards regression and meta-analysis on individual participant data were performed.
Results: Median RDW values varied across studies from 13.2% to 14.6%. During 68,822 person-years of follow-up of 11,827 older adults with RDW measured, there was a graded increased risk of death associated with higher RDW values (p < .001). For every 1% increment in RDW, total mortality risk increased by 14% (adjusted hazard ratio [HR]: 1.14; 95% confidence interval [CI]: 1.11–1.17). In addition, RDW was strongly associated with deaths from CVD (adjusted HR: 1.15; 95% CI: 1.12–1.25), cancer (adjusted HR: 1.13; 95% CI: 1.07–1.20), and other causes (adjusted HR: 1.13; 95% CI: 1.07–1.18). Furthermore, the RDW–mortality association occurred in all major demographic, disease, and nutritional risk factor subgroups examined. Among the subset of 1,603 older adults without major age-associated diseases, RDW remained strongly associated with total mortality (adjusted HR: 1.32; 95% CI: 1.21–1.44).
Conclusions: RDW is a routinely reported test that is a powerful predictor of mortality in community-dwelling older adults with and without age-associated diseases. The biologic mechanisms underlying this association merit investigation.
Keywords Aging; Erythrocyte Indices; Mortality; Risk Factors
Received: October 2, 2009; Accepted: October 6, 2009