Prevalence and possible causes of anemia in the elderly: a cross-sectional analysis of a large European university hospital cohort.

BACKGROUND: Anemia in later life is associated with increased morbidity and mortality. The purpose of this study was to evaluate the prevalence and possible causes of anemia in the elderly in a well defined hospital cohort.

METHODS: Participants in this cross-sectional, retrospective analysis included all inpatients and outpatients aged ≥64 years with complete blood counts treated at Innsbruck Medical University Hospital between October 1, 2004 and September 29, 2005 (n=19,758, median age 73 years).

RESULTS: According to World Health Organization criteria, 21.1% of these patients were anemic, ie, 30.7% and 37.0% at 80+ years and 90+ years, respectively. The prevalence of anemia was significantly correlated with advanced age (r=0.21; P<0.001) and male sex (P<0.001). In anemic patients, renal insufficiency with a glomerular filtration rate <30 mL/min/1.73 m(2) (11.3% versus 2.1%), hyperinflammation (62.1% versus 31.4%), absolute (14.4% versus 6.9%) or functional (28.2% versus 11.8%) iron deficiency, and folate deficiency (6.7% versus 3.0%) were observed significantly more often than in nonanemic subjects (P<0.001). The pathogenesis of anemia was multifactorial, with decreased renal function (glomerular filtration rate <60 mL/min/1.73 m(2)), signs of inflammation, and functional iron deficiency detected in 11.4% of anemic patients. Hemoglobin was significantly correlated with elevated C-reactive protein (r= -0.296; P<0.001) and low transferrin saturation (r=0.313; P<0.001). Mean corpuscular volume correlated only weakly with the various anemia subtypes. Cytopenias and morphologic alterations suggestive of underlying myelodysplastic syndromes were found in a substantial proportion of anemic patients, including thrombocytopenia (5.4%), leukopenia (8.26%), and macrocytic alterations (18.4%).

CONCLUSION: Anemia was frequently diagnosed in this series of elderly patients. Partly treatable nutritional deficiencies, such as iron or folate deficiency, were identified as possible causes. A complex and heterogeneous interplay of chronic inflammation, functional iron deficiency, and renal impairment was identified in a large proportion of patients. A hitherto undiagnosed myelodysplastic syndrome can be assumed in a relevant proportion of patients. Morphologic classification based on mean corpuscular volume is inadequate from the standpoint of pathogenesis. New parameters are needed to differentiate the multifactorial pathogenesis of anemia in the elderly.