What is it about?
ABSTRACT Background Anemia is an independent risk factor for morbidity and mortality in an array of disorders common to seniors including cancer, renal disease and heart disease. The aim of this study was to identify the frequency of RBC abnormalities and the utility of laboratory tests for detection of anemia and its cause in the hospitalized elderly. Method A prospective analysis was performed on 140 consecutive adults over age 65 who had chronic diseases (mean age 72, range 65-80). Laboratory tests included hemoglobin (HGB), hematocrit (HCT), red cell indices (mean cell volume (MCV), mean cellular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) red cell distribution width (RDW), reticulocyte count (RET), serum iron, total iron binding capacity, and index saturation transferrin( IST). Results: Only a minority of patients, 33 patients (23.58%) had normal results for all hematological tests. An additional 16 (11.4%) patients had normal HGB and HCT, bur low MCV or MCH. Conclusions Anemia is common in older chronically ill adults. Routine anemia screening should be recommended in hospitalized chronically ill adults over persons 65 years and the WHO must be redefine the anemia by these common parameters. Abbreviations: ACD = Anemia of Chronic Disease; CFR- Chronic Renal Failure; CBC =complete blood count; CHr = reticulocyte hemoglobin; EPO = erythropoietin; HGB= hemoglobin; HCT = hematocrit;; IDA = iron deficiency anemia; IST = index saturation transferrin; MA = megaloblastic anemia; MCV = mean cell volume; MCH = mean cellular hemoglobin; MCHC = mean cell hemoglobin concentration; RPI=Reticulocyte Production Index; TS = transferrin saturation; RDW = red cell distribution width; RET = reticulocyte count; SI = serum iron; sTR = soluble transferrin receptor; TIBC = total iron binding capacity.
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Why is it important?
Epidemiologic studies have suggested that anemia may be associated with poorer outcomes in a variety of disorders. In many studies the definition of anemia used is that suggested by a World Health Organization (WHO) expert committee over 40 years ago. The WHO criteria define anemia by hemoglobin (HGB) concentration of < 130 g/L for adult men and<120 g/L for adult females. [1] Results from the 1988-1994 United States National Health and Nutrition Examination Survey (NHANES III) indicate that fewer than 3% of adults aged 65 and older have hemoglobin levels below 110 g/L, and therefore most anemia cases among community-dwelling older adults are mild [2]. Nonetheless, recent evidence indicates that even mild anemia is independently associated with increased risk of recurrent falls, poorer physical function, hospitalization, and mortality in older adults. [3] While a number of studies have reported differential distributions of anemia by age and sex, less attention has been devoted to disparities in anemia by race. According to NHANES III estimates, older non-Hispanic blacks were 3 times more likely to have anemia compared to older non-Hispanic whites (27.8% vs 9.0%). [1]. Similar disparities in anemia prevalence have been observed in other population-based studies of older blacks and whites.[4, 5]. These observations have led some to consider race-specific criteria for defining anemia. [6] Anemia in the elderly is an extremely common problem that is associated with increased mortality and poorer health-related quality of life, regardless of the underlying cause of the low hemoglobin. A recent study in Iceland defined mild anemia as a hemoglobin concentration between 10.0 and 11.9 g/dL in women and between 10.0 and 12.9 g/dL in men [7]. This cross-sectional analysis provides evidence of anemia in 36.7% of hospitalized patients, and shows an association among anemia, poor nutritional status, and inflammation[ 8]. Future research on anemia in the elderly should focus on the age-related physiologic changes underlying this condition and whether anemia correction can reduce anemia-associated risks, and improve quality of life [9]. The purpose of this study was to determine the prevalence and causes of anemia among older adults hospitalized at an academic medical center.
Perspectives
In a longitudinal study in healthy elderly subjects, HGB slowly but predictably declined with aging. An inverse relationship between hemoglobin and all-cause mortality was observed; the lowest risk for mortality occurred at hemoglobin values between 130-150 g/L for women and 140-170 g/L for men. The anemia is associated with an increased risk for hospitalization and death in community-dwelling older adults. [9] This study conforms that abnormal hematologic parameters are common in elderly individuals. [54.2% to men versus 40.6% to women ]. The most common cause of anemia was chronic disease anemia, which can include a variety of underlying disorders. The peptide hormone hepcidin, secreted by the liver, controls plasma iron concentration by inhibiting iron export from macrophages and decreased absorption of iron from the intestine. Hepcidin is increased in anemia of chronic disease. [12]. Hypochromic, microcytic anemia due to iron deficiency (IDA) was an uncommon cause of anemia in the elderly patients in the current study (15%), while it is a common cause of anemia in younger individuals [13, 14]. In this study, the presence of hypochromic cells representing >10% of total RBC was considered functional iron deficiency (ID), when confirmed by low serum iron. Various cut off values for functional ID is reported in literature ranging from 2% to 10% hypocromic cells. [17] IDA must be differentiated from ACD [11] and thalassemia [12], which can also cause microcytosis. Measuring TIBC is an indirect method of assessing transferrin, which is typically low in ACD, normal or low in thalassemia, and high in IDA. Unexplained anemia is generally a condition of elderly persons. It appears more commonly with advancing age and is rarely, if ever, encountered in younger adults [15, 16]. Even with the advent of better tests such as serum ferritin, methylmalonic acid, and soluble transferrin receptor, a significant portion of elderly persons with anemia will continue to have unexplained anemia. Bone marrow examination, including staining for hemosiderin have been be reccomanded in most elderly patients to determine if anemia is due to Myelodysplastic Syndrome. [17] Conclusions In elderly persons, the etiologies of anemia differ sufficiently from those in younger adults to warrant considering anemia in elderly persons as a distinct entity. In this study, anemia of aging was found in 65% of patients overall, and in over 90% of older adults with chronic renal failure. Diagnosis of causes must rely on laboratory medicine results along with interpretation based on the clinician’s interpretation. Routine anemia screening using CBC is indicated in elderly hospitalized elderly, individually. An iron panel is useful in differentiating anemia of chronic disease from iron deficiency.
Professor Aurelian Udristioiu
Hematology and Oncology Specialists LLC
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This page is a summary of: Screening Tests for Latent Anemia in Hospitalized Adults Over the Age of 65, Laboratory Medicine, May 2010, Oxford University Press (OUP),
DOI: 10.1309/lm21vxh1efugxbbn.
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