Serum transferrin receptor in the evaluation of the iron status in elderly hospitalized patients with anemia

Biomarkers of erythropoiesis response to intravenous iron in a crossover pilot study in unexplained anemia of the elderly

Anemia is common in older adults, but often unexplained. Previously, we conducted a randomized, controlled trial of intravenous (IV) iron sucrose to study its impact on the 6-minute walk test and hemoglobin in older adults with unexplained anemia and ferritin levels of 20-200 ng/mL. In this report, we present for the first time the response of hemoglobin, as well as the dynamic response of biomarkers of erythropoiesis and iron indices, in a pooled analysis of the initially IV iron-treated group of 9 subjects and the subsequently IV iron treated 10 subjects from the delayed treatment group. We hypothesized that there would be a reproducible hemoglobin response from IV iron, and that iron indices and erythropoietic markers would reflect appropriate iron loading and reduced erythropoietic stress. To investigate the biochemical response of anemia to IV iron, we studied the dynamics of soluble transferrin receptor (STfR), hepcidin, erythropoietin (EPO), and iron indices over 12 weeks after treatment. In total, all 19 treated subjects were evaluable: 9 from initial treatment and 10 after cross-over. Hemoglobin rose from 11.0 to 11.7 g/dL, 12 weeks after initiating IV iron treatment of 1000 mg divided weekly over 5 weeks. We found early changes of iron loading after 1-2 IV iron dose: serum iron increased by 184 mcg/dL from a baseline of 66 mcg/dL, ferritin by 184 ng/mL from 68 ng/mL, and hepcidin by 7.49 ng/mL from 19.2 ng/mL, while STfR and serum EPO declined by 0.55 mg/L and 3.5 mU/mL from 19.2 ng/mL and 14 mU/mL, respectively. The erythroid response and evidence of enhanced iron trafficking are consistent with the hypothesis that IV iron overcomes iron deficient or iron-restricted erythropoiesis. These data provide new insight that iron-restricted erythropoiesis is a potential and targetable mechanism for patients diagnosed with unexplained anemia of the elderly and offers support for larger prospective trials of IV iron among anemic older adults of low to normal ferritin.

Iron deficiency and biomarkers of inflammation: a 3-year prospective analysis of the DO-HEALTH trial

Background

The longitudinal association between iron deficiency and inflammatory biomarkers levels has not been fully explored among relatively healthy older adults.

Aims

To assess whether iron deficiency at baseline and at any yearly follow-up time point, with or without anemia, was associated with changes from baseline in high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6) levels over 3 years.

Methods

This is a post-hoc observational analysis of DO-HEALTH, a double-blind, randomized controlled trial including 2157 European community-dwelling adults age 70+. The outcomes were changes from baseline in hs-CRP and IL-6 levels, measured at 12, 24, and 36 months of follow-up. Iron deficiency was defined by soluble transferrin receptor levels > 28.1 nmol/L and baseline anemia by hemoglobin levels < 130 g/L for men and < 120 g/L for women.

Results

In total, 2141 participants were included in the analyses (mean age: 74.9 years, 61.5% of women, 26.8% with iron deficiency). Baseline iron deficiency was associated with greater increase in IL-6 levels (mean difference in change: 0.52 ng/L, 95%CI 0.03–1.00, P = .04) over 3 years. Iron deficiency at any yearly time point was associated with higher increases in hs-CRP (mean difference in change: 1.62 mg/L, 95%CI 0.98–2.26, P < .001) and IL-6 levels (mean difference in change: 1.33 ng/L, 95%CI 0.87–1.79, P < .001) over 3 years. No significant interaction between iron deficiency and anemia was found, suggesting that the results are independent of the anemic status.

Conclusions

These findings suggest that iron deficiency may play a role in low-grade chronic inflammation among relatively healthy older adults.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40520-021-01955-3.

Iron Deficiency and Incident Infections among Community-Dwelling Adults Age 70 Years and Older: Results from the DO-HEALTH Study

OBJECTIVES

To assess if baseline iron deficiency, with or without anemia, is associated with incident infections over 3 years among community-dwelling older adults.

DESIGN

Prospective secondary analysis of DO-HEALTH, a 3-year randomized, double-blind controlled trial.

SETTING AND PARTICIPANTS

2157 community-dwelling adults age 70+ from 5 European countries with good cognitive function and mobility and no major health events in the 5 years prior to enrollment Measurements: Incident infections, their severity and type were recorded every 3 months throughout the 3-year follow-up. Iron deficiency was defined as soluble transferrin receptor (sTfR) levels > 28.1 nmol/l and anemia as hemoglobin levels < 120 g/l for women and 130 g/l for men. We applied negative binomial mixed effects regression models with random effects for countries, and controlling for treatment allocation, age, sex, body mass index, polypharmacy, number of comorbidities, smoking status, living situation, alcohol intake, frailty status, and physical activity levels. A pre-defined stratified analysis was performed to explore if the associations between iron deficiency and infections were consistent by baseline anemia status.

RESULTS

In total, 2141 participants were included in the analyses (mean age 74.9 years, 61.5% of women, 26.8% with iron deficiency). Across all participants, baseline iron deficiency was not associated with incident overall infections, but was associated with a 63% greater rate of incident severe infections requiring hospitalization (incidence rate ratio [IRR] 1.63, 95% Confidence Interval [CI] 1.11-2.41, p=0.01). This association was more pronounced among the 2000 participants who did not have anemia at baseline (IRR=1.80, 95% CI 1.20-2.69, p=0.005).

CONCLUSION

Based on this prospective study among generally healthy European community-dwelling older adults, iron deficiency was not associated with the incidence rate of overall infections but may increase the incidence of severe infections. Intervention studies are needed to prove the causality of this observation.

Serum or plasma ferritin concentration as an index of iron deficiency and overload

BACKGROUND

Reference standard indices of iron deficiency and iron overload are generally invasive, expensive, and can be unpleasant or occasionally risky. Ferritin is an iron storage protein and its concentration in the plasma or serum reflects iron stores; low ferritin indicates iron deficiency, while elevated ferritin reflects risk of iron overload. However, ferritin is also an acute-phase protein and its levels are elevated in inflammation and infection. The use of ferritin as a diagnostic test of iron deficiency and overload is a common clinical practice.

OBJECTIVES

To determine the diagnostic accuracy of ferritin concentrations (serum or plasma) for detecting iron deficiency and risk of iron overload in primary and secondary iron-loading syndromes.

SEARCH METHODS

We searched the following databases (10 June 2020): DARE (Cochrane Library) Issue 2 of 4 2015, HTA (Cochrane Library) Issue 4 of 4 2016, CENTRAL (Cochrane Library) Issue 6 of 12 2020, MEDLINE (OVID) 1946 to 9 June 2020, Embase (OVID) 1947 to week 23 2020, CINAHL (Ebsco) 1982 to June 2020, Web of Science (ISI) SCI, SSCI, CPCI-exp & CPCI-SSH to June 2020, POPLINE 16/8/18, Open Grey (10/6/20), TRoPHI (10/6/20), Bibliomap (10/6/20), IBECS (10/6/20), SCIELO (10/6/20), Global Index Medicus (10/6/20) AIM, IMSEAR, WPRIM, IMEMR, LILACS (10/6/20), PAHO (10/6/20), WHOLIS 10/6/20, IndMED (16/8/18) and Native Health Research Database (10/6/20). We also searched two trials registers and contacted relevant organisations for unpublished studies.

SELECTION CRITERIA

We included all study designs seeking to evaluate serum or plasma ferritin concentrations measured by any current or previously available quantitative assay as an index of iron status in individuals of any age, sex, clinical and physiological status from any country.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods. We designed the data extraction form to record results for ferritin concentration as the index test, and bone marrow iron content for iron deficiency and liver iron content for iron overload as the reference standards. Two other authors further extracted and validated the number of true positive, true negative, false positive, false negative cases, and extracted or derived the sensitivity, specificity, positive and negative predictive values for each threshold presented for iron deficiency and iron overload in included studies. We assessed risk of bias and applicability using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 tool. We used GRADE assessment to enable the quality of evidence and hence strength of evidence for our conclusions.

MAIN RESULTS

Our search was conducted initially in 2014 and updated in 2017, 2018 and 2020 (10 June). We identified 21,217 records and screened 14,244 records after duplicates were removed. We assessed 316 records in full text. We excluded 190 studies (193 records) with reasons and included 108 studies (111 records) in the qualitative and quantitative analysis. There were 11 studies (12 records) that we screened from the last search update and appeared eligible for a future analysis. We decided to enter these as awaiting classification. We stratified the analysis first by participant clinical status: apparently healthy and non-healthy populations. We then stratified by age and pregnancy status as: infants and children, adolescents, pregnant women, and adults. Iron deficiency We included 72 studies (75 records) involving 6059 participants. Apparently healthy populations Five studies screened for iron deficiency in people without apparent illness. In the general adult population, three studies reported sensitivities of 63% to 100% at the optimum cutoff for ferritin, with corresponding specificities of 92% to 98%, but the ferritin cutoffs varied between studies. One study in healthy children reported a sensitivity of 74% and a specificity of 77%. One study in pregnant women reported a sensitivity of 88% and a specificity of 100%. Overall confidence in these estimates was very low because of potential bias, indirectness, and sparse and heterogenous evidence. No studies screened for iron overload in apparently healthy people. People presenting for medical care There were 63 studies among adults presenting for medical care (5042 participants). For a sample of 1000 subjects with a 35% prevalence of iron deficiency (of the included studies in this category) and supposing a 85% specificity, there would be 315 iron-deficient subjects correctly classified as having iron deficiency and 35 iron-deficient subjects incorrectly classified as not having iron deficiency, leading to a 90% sensitivity. Thresholds proposed by the authors of the included studies ranged between 12 to 200 µg/L. The estimated diagnostic odds ratio was 50. Among non-healthy adults using a fixed threshold of 30 μg/L (nine studies, 512 participants, low-certainty evidence), the pooled estimate for sensitivity was 79% with a 95% confidence interval of (58%, 91%) and specificity of 98%, with a 95% confidence interval of (91%, 100%). The estimated diagnostic odds ratio was 140, a relatively highly informative test. Iron overload We included 36 studies (36 records) involving 1927 participants. All studies concerned non-healthy populations. There were no studies targeting either infants, children, or pregnant women. Among all populations (one threshold for males and females; 36 studies, 1927 participants, very low-certainty evidence): for a sample of 1000 subjects with a 42% prevalence of iron overload (of the included studies in this category) and supposing a 65% specificity, there would be 332 iron-overloaded subjects correctly classified as having iron overload and 85 iron-overloaded subjects incorrectly classified as not having iron overload, leading to a 80% sensitivity. The estimated diagnostic odds ratio was 8.

AUTHORS' CONCLUSIONS

At a threshold of 30 micrograms/L, there is low-certainty evidence that blood ferritin concentration is reasonably sensitive and a very specific test for iron deficiency in people presenting for medical care. There is very low certainty that high concentrations of ferritin provide a sensitive test for iron overload in people where this condition is suspected. There is insufficient evidence to know whether ferritin concentration performs similarly when screening asymptomatic people for iron deficiency or overload.

Role of Soluble Transferrin Receptor and Transferrin Receptor-Ferritin Index to Detect Iron Deficiency Anemia in Regular Hemodialysis Patients

BACKGROUND:

Several iron indicators can be used to detect iron deficiency anaemia (IDA) where confounding comorbidities occurred such as patients with regular hemodialysis.

AIM:

This study was aimed to determine the diagnostic value of serum transferrin receptor (sTfR) and transferrin receptor-transferrin index (TfR-F index) and to combine these two markers in detecting IDA in regular hemodialysis anaemic patients.

METHODS:

There were 70 patients recruited consecutively. IDA was diagnosed based on TS < 20% and ferritin level < 200 ng/L and functional iron deficiency when TS < 20% and ferritin > 200 ng/L. TfR-F index calculated as sTfR/log ferritin.

RESULTS:

Correlation of ferritin to iron level was changed when its correlation adjusted by confounding inflammation (CRP level > 10). The correlation strength of ferritin to iron serum before adjusted was r = 0.37 with p = 0.02 but became r = 0.65 with p = 0.023 after adjusted to CRP > 10. In inflammation (CRP > 10), ferritin mild-moderately correlated with iron but became moderately strong when there was no inflammation (CRP < 10). AUC for sTfR was 0.77 with p = 0.028 (95% CI 0.55-0.99), and for TfR-F index has larger AUC 0.85% with p = 0.004 (95%CI 0.69-1.00), hence TfR-F index more superior than sTfR. sTfR and sTfR-F index were not correlated with CRP with p > 0.05, and sTfR and TfR-F index mean level was different between IDA and ACD patients although not statistically significant.

CONCLUSION:

When sTfR and the TfR-F index used in combination to detect IDA, we found the largest AUC on ROC 0.98 (95% CI 0.94-1.00).

Iron deficiency anemia in older adults: A review

Anemia in older adults is a risk factor for numerous negative outcomes. There is no standard definition, but in most studies, anemia is defined as a hemoglobin value <12 g/dL for women and <13 g/dL for men. Absolute iron deficiency anemia is defined as the combination of anemia and the absence of total body iron. Serum ferritin is the most frequently used diagnostic parameter, but its concentration increases with age and in the presence of inflammatory diseases. Other laboratory tests, such as transferrin saturation, soluble transferrin receptor and the soluble transferrin receptor/ferritin index might provide useful information, but there is a wide variety in the cut-off values and interpretation of the results. Recent research regarding hepcidin as a central regulator of iron homeostasis is promising, but it has not been used yet for the routine diagnosis of iron deficiency anemia. In older iron deficiency anemia patients, an esophagogastroduodenoscopy and colonoscopy should be initiated in order to identify the underlying bleeding cause. CT colonography can replace a colonoscopy, and in specific cases, a video capsule is recommended. It remains crucial to keep in mind which potential benefits might be expected from these investigations in this vulnerable population, taking into account the comorbidity and life expectancy, and one should discuss in advance the possible therapeutic options and complications with the patient, a family member or a proxy. Oral iron administration is the standard treatment, but parenteral iron is a convenient and safe way to provide the total iron dose in one or a few sessions. Geriatr Gerontol Int 2018; 18: 373-379.

[Iron deficiency in the elderly]

Anemia is a common diagnosis in the geriatric population, especially in institutionalized and hospitalized elderly. Most common etiologies for anemia in elderly people admitted to a geriatric ward are iron-deficiency anemia and anemia associated with chronic disease. Determination of serum ferritin is the most used assay in the differential diagnosis, despite low sensitivity and moderate specificity. New insights into iron homeostasis lead to new diagnostic assays such as serum hepcidin, serum transferrin receptor and reticulocyte hemoglobin equivalent.Importance of proper diagnosis and treatment for this population is large since there is a correlation between anemia and morbidity - mortality. Anemia is usually defined as hemoglobin less than 12 g/dl for women and less than 13 g/dl for men. There is no consensus for which hemoglobinvalue an investigation into underlying pathology is obligatory. This needs to be evaluated depending on functional condition of the patient.

[The first pillar of patient blood management. Types of anemia and diagnostic parameters]

Patient Blood Management (PBM) is the design of a personalized, multimodal multidisciplinary plan for minimizing transfusion and simultaneously achieving a positive impact on patient outcomes. The first pillar of PBM consists of optimizing the erythrocyte mass. The best chance for this step is offered by preoperative preparation. In most cases, a detailed medical history, physical examination and laboratory tests will identify the cause of anemia. A correct evaluation of parameters that assess the state and function of iron, such as ferritin levels, and the parameters that measure functional iron, such as transferrin saturation and soluble transferrin receptor levels, provide us with essential information for guiding the treatment with iron. The new blood count analyzers that measure hypochromia (% of hypochromic red blood cells and reticulocyte hemoglobin concentrations) provide us useful information for the diagnosis and follow-up of the response to iron treatment. Measuring serum folic acid and vitamin B12 levels is essential for treating deficiencies and thereby achieving better hemoglobin optimization.

Serum ferritin is an important inflammatory disease marker, as it is mainly a leakage product from damaged cells

"Serum ferritin" presents a paradox, as the iron storage protein ferritin is not synthesised in serum yet is to be found there. Serum ferritin is also a well known inflammatory marker, but it is unclear whether serum ferritin reflects or causes inflammation, or whether it is involved in an inflammatory cycle. We argue here that serum ferritin arises from damaged cells, and is thus a marker of cellular damage. The protein in serum ferritin is considered benign, but it has lost (i.e. dumped) most of its normal complement of iron which when unliganded is highly toxic. The facts that serum ferritin levels can correlate with both disease and with body iron stores are thus expected on simple chemical kinetic grounds. Serum ferritin levels also correlate with other phenotypic readouts such as erythrocyte morphology. Overall, this systems approach serves to explain a number of apparent paradoxes of serum ferritin, including (i) why it correlates with biomarkers of cell damage, (ii) why it correlates with biomarkers of hydroxyl radical formation (and oxidative stress) and (iii) therefore why it correlates with the presence and/or severity of numerous diseases. This leads to suggestions for how one might exploit the corollaries of the recognition that serum ferritin levels mainly represent a consequence of cell stress and damage.

Case-control study of anaemia among middle-aged and elderly women in three rural areas of China

OBJECTIVES

To propose a feasible suggestion to reduce the high prevalence of anaemia in middle-aged and elderly women by investigating risk factors, particularly nutritional factors, and analysing the effect on anaemia in three different rural areas of China.

DESIGN

A case-control study.

SETTING

Three counties of China.

PARTICIPANTS

Women aged 50-75 years in the three counties.

MAIN OUTCOME MEASURES

Adjusted OR (95% CI) of anaemia associated with diet, lifestyle and blood biochemical indices.

RESULTS

Compared with controls, women with anaemia had lower body mass index (22.1 (3.2) kg/m(2) vs 23.2 (3.5) kg/m(2); p<0.001), a higher experience of shortage of food (45.0% vs 36.5%; p<0.001), less soy food intake (0.5 (0.3, 26.7) g/day vs 5.6 (0.4, 27.8) g/day; p<0.048), lower serum iron (13.4 (5.4) μmol/L vs 16.4 (5.7) μmol/L; p<0.001), lower ferritin (109.6 (85.6) ng/mL vs 131.0 (92.0) ng/mL; p<0.001), lower transferrin saturation levels (22.5 (9.5)% vs 26.8 (9.6)%; p<0.001) and higher levels of free erythrocyte protoporphyrin (42.4 (21.2) μg/dL vs 39.6 (17.8) μg/dL; p<0.001). Anaemia was significantly associated with BMI(OR=0.90, 95% CI (0.87 to 0.92)), food shortage experience (OR=1.39, 95% CI (1.15 to 1.69)), total protein (OR=0.66, 95%CI (0.54 to 0.80)), Albumin (OR=0.72, 95%CI (0.59 to 0.87)) in univariate analysis. Multivariate analysis showed that body mass index, experience of food shortage, total protein and albumin were independently related to anaemia.

CONCLUSIONS

Among middle-aged and elderly women in rural China, the nutrition status of anaemic cases is far below that of controls. Lower body mass index and a greater experience of food shortage are closely related to anaemia. Improving the blood protein status by consuming protein-sufficient foods such as soy food is a feasible approach for elderly anaemic women. Further research is needed on the effect of chronic inflammation and infectious disease on anaemia in elderly women in rural China.

Is analysis of the reticulocyte haemoglobin equivalent a useful test for the diagnosis of iron deficiency anaemia in geriatric patients?

BACKGROUND

Iron deficiency anaemia (IDA) and anaemia of chronic disease (ACD) are common in elderly patients but there are no standard diagnostic criteria. The reticulocyte haemoglobin equivalent (Ret-He) is routinely measured by modern automated blood analysers and is an early indicator of iron deficiency. The aim of this study was to investigate whether the Ret-He level as calculated by the Sysmex XE-5000 automated blood analyser is a useful parameter for the diagnosis of IDA in a geriatric hospitalized population.

METHODS

In a prospective study, blood samples were collected in 26 geriatric patients with IDA and 111 patients with ACD diagnosed according to generally accepted laboratory and clinical criteria. A blood count including Ret-He, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) and standard iron parameters was performed in each patient.

RESULTS

Haemoglobin, Ret-He, MCV, MCH and MCHC levels were all significantly lower in IDA as compared to ACD patients. However, the area under the curve (AUC) was greater for MCH (0.87, 95% CI 0.78-0.95) and MCHC (0.86, 95% CI 0.76-0.96) then for Ret-He (0.828, 95% CI 0.73-0.93) and MCV (0.80, 95% CI 0.68-0.91). A Ret-He cut-off value of 26 pg had a sensitivity and specificity based on its optimal combination of 85% and 69% respectively.

CONCLUSION

Analysis of Ret-He does not perform better than the classical red cell indices such as MCH and MCHC in differentiating IDA and ACD in geriatric patients.

Soluble transferrin receptor (sTfR) and sTfR/log ferritin index for the diagnosis of iron-deficiency anemia. A meta-analysis

Determination of serum soluble transferrin receptor (sTfR) is proposed to distinguish between iron-deficiency anemia and anemia of chronic disease. Here we conducted a meta-analysis of the literature to evaluate the diagnostic efficacy of sTfR and sTfR/log ferritin index. The meta-analysis included 18 sTfR and 10 sTfR index studies. Three sTfR index studies were, however, eliminated as outliers. The odds ratio was significant for both sTfR (22.9, 95% confidence interval [CI], 9.6-55.0) and sTfR index (9.5, 95% CI, 5.0-18.1) in a heterogeneous set of studies. Meta-analysis for sensitivity, specificity, and likelihood ratios (LRs) was performed only in a subset of 10 sTfR studies. The overall sensitivity, specificity, and positive and negative LRs were 86%, 75%, 3.85, and 0.19, respectively, with an area under summary receiver operating characteristic curve of 0.912 (standard error, 0.039). Additional studies are needed to define the overall diagnostic accuracy of sTfR.

Evaluation of the first commercial hepcidin ELISA for the differential diagnosis of anemia of chronic disease and iron deficiency anemia in hospitalized geriatric patients

Introduction. Anemia is a frequent problem in hospitalized geriatric patients, and the anemia of chronic disease (ACD) and iron deficiency anemia (IDA) are the 2 most prevalent causes. The aim of the study was to assess the possible role of serum hepcidin in the differential diagnosis between ACD and IDA. Methods. We investigated serum hepcidin, iron status, anemia, and C-reactive protein in 39 consecutive geriatric patients with ACD and IDA. Serum hepcidin levels were determined using a commercial ELISA kit (DRG Instruments, Marburg, Germany). We also measured hepcidin in 26 healthy controls. Results. The serum hepcidin levels were not significantly higher in the 28 patients with ACD as compared to the 11 patients with IDA. Conclusions. The serum hepcidin levels measured using the commercial ELISA kit (DRG) do not appear to increase in older patients with ACD. It should be noted that an assay-specific problem could explain our results.

Impaired iron status in aging research

Aging is associated with disturbances in iron metabolism and storage. During the last decade, remarkable progress has been made toward understanding their cellular and molecular mechanisms in aging and age-associated diseases using both cultured cells and animal models. The field has moved beyond descriptive studies to potential intervention studies focusing on iron chelation and removal. However, some findings remain controversial and inconsistent. This review summarizes important features of iron dyshomeostasis in aging research with a particular emphasis on current knowledge of the mechanisms underlying age-associated disorders in rodent models.

Relationship between depressive symptoms, anemia, and iron status in older residents from a national survey population

OBJECTIVE

To investigate the association between iron deficiency status and depressive symptoms in a national community sample of older people.

METHODS

Cross-sectional data were analyzed from 1875 participants 65 years and older who had participated in the 2005 Health Survey for England. Serum hemoglobin (Hb), ferritin, and transferrin receptor levels and depressive symptoms (Geriatric Depression Scale) had been measured. Covariates included age, sex, occupation, multivitamin intake, smoking status, body mass index, hypertension, heart disease, stroke, diabetes, and cancer.

RESULTS

Depressive symptoms were associated with anemia (Hb <12.0 g/dL for women and <13.0 g/dL for men; present in 10.8%; odds ratio [OR] = 1.53 [95% confidence interval = 1.08-2.18]) after adjustment for age, sex, social class, multivitamin intake, smoking status, and body mass index, but this association was reduced substantially after further adjustment for physical health status (OR = 1.14). Low serum ferritin level (<45 ng/mL; present in 21.6%) was associated with depressive symptoms after full adjustment (OR = 1.37 [95% confidence interval = 1.03-1.81]). Linear models, however, revealed significant associations between higher number of depressive symptoms and lower Hb level and higher serum transferrin receptor level but not with ferritin levels.

CONCLUSIONS

Iron deficiency commonly co-occurs with depressive symptoms in older people, although the association with anemia is accounted for by physical health status and may primarily reflect anemia of chronic disease.

Unexplained anemia predominates despite an intensive evaluation in a racially diverse cohort of older adults from a referral anemia clinic

BACKGROUND

To accurately determine the causes of anemia and proportion of unexplained anemia in a racially diverse cohort of older adults after a comprehensive and standardized evaluation.

METHODS

We evaluated results from a single-institutional university anemia clinic. Patients with anemia, defined as a hemoglobin less than 13.0 g/dL for men and less than 12.0 g/dL for women, underwent a prospective standardized history, physical examination, and laboratory measures, with additional studies including bone marrow examination as indicated. Empiric treatment trials were given for identified deficiencies.

RESULTS

One hundred and seventy-four primarily community-dwelling adults aged 65 years and older were evaluable. African Americans accounted for 69% of patients and whites were 27%. Anemia etiologies included iron deficiency anemia at 25.3%, anemia of chronic inflammation at 9.8%, and hematologic malignancy in 7.5%. Unexplained anemia in the elderly accounted for 43.7% and predominated in both African Americans and whites. The prevalence of iron deficiency anemia and hematologic malignancies did not differ by race. Unexplained anemia in the elderly showed a consistent phenotype composed of a hypoproliferative mild-to-moderate anemia with suppressed serum erythropoietin. Specifically, erythropoietin levels showed no correlation with hemoglobin concentration in unexplained anemia in the elderly (r = -.15, p = .19) as opposed to iron deficiency anemia (r = -.63, p < .0001).

CONCLUSIONS

In summary, an intensive hematologic evaluation reveals a wide number of anemia etiologies among older adults, including 7.5% with hematologic malignancies; nevertheless, unexplained anemia in the elderly prevails as the most common category in whites and African Americans.

Iron deficiency anemia

The most severe consequence of iron depletion is iron deficiency anemia (IDA), and it is still considered the most common nutrition deficiency worldwide. Although the etiology of IDA is multifaceted, it generally results when the iron demands by the body are not met by iron absorption, regardless of the reason. Individuals with IDA have inadequate intake, impaired absorption or transport, physiologic losses associated with chronological or reproductive age, or chronic blood loss secondary to disease. In adults, IDA can result in a wide variety of adverse outcomes including diminished work or exercise capacity, impaired thermoregulation, immune dysfunction, GI disturbances, and neurocognitive impairment. In addition, IDA concomitant with chronic kidney disease or congestive heart failure can worsen the outcome of both conditions. In this review, the prevalence of IDA related to confounding medical conditions will be described along with its diverse etiologies. Distinguishing IDA from anemia of chronic disease using hematologic measures is reviewed as well. In addition, current diagnostic strategies that are inclusive of clinical presentation, biochemical tests, and differential diagnosis will be outlined, followed by a discussion of treatment modalities and future research recommendations.

The role of iron in restless legs syndrome

The impressive relief from restless legs syndrome (RLS) symptoms provided by levodopa treatment indicates RLS is caused by a dopaminergic abnormality. But similar and more lasting relief also occurs for iron treatment in some patients. Thus there are two major putative causes for RLS: CNS dopaminergic abnormality and CNS iron insufficiency. This article presents the data documenting that both peripheral and CNS iron insufficiency occur with RLS symptoms. Brain iron insufficiency is supported by independently replicated cerebrospinal fluid and brain imaging studies for patients without iron deficiency (ID) anemia. Autopsy studies and intravenous iron treatment further link brain iron insufficiency to RLS. The brain iron insufficiency in patients with RLS is now well established. In this article the data are reviewed that support the following postulates combining dopaminergic and iron causes of RLS: (1) All conditions that compromise iron availability will increase the risk of RLS leading to a higher than expected prevalence of RLS in these conditions. (2) Some patients with RLS have marginal CNS iron status that can become insufficient when deprived of normal access to adequate peripheral iron or may be insufficient even with normal access to adequate peripheral iron. (3) The change or reduced CNS iron status produces RLS symptoms largely through its effects on the dopaminergic system and the corollary to 3. (4) Dopaminergic system abnormalities producing RLS symptoms will be included in those produced by brain ID. Study of the iron model of RLS offers hope for developing new treatment approaches and perhaps methods to prevent or cure the disorder.

Correct assessment of iron depletion and iron deficiency anemia

OBJECTIVE

Iron deficiency anemia is caused by decreased production of red blood cells (RBCs) and is characterized by a reduction in either the hematocrit (Ht) or the concentration of hemoglobin (Hb). It is detected by blood iron status measures that are below population reference standards and also below the "usual or normal" levels for an individual. In some medicine practices, usually only hemoglobin and hematocrit are routinely measured with a full blood count, without measuring the indicators of iron status. Biochemical measures that are collected on single occasion are difficult to interpret in individuals, and normal ranges of hemoglobin and hematocrit do not necessarily confirm an iron deficiency condition, because they decrease only when severe iron depletion is present and are often unreliable or misleading. Thus, iron-depleted individuals can quickly develop iron deficiency if not detected early.

METHODS

Information from hematological laboratory tests records on female patients at reproductive ages were collected and analysed.

RESULTS

In this study, measurement of general test for anemia in some individuals revealed normal levels of RBCs count, Hb, Ht, mean corpuscular volume (MCV), mean cell hemoglobin concentration (MCHC), and cell morphology, whereas the levels of parameters of iron depletion and iron deficiency anemia such as serum iron and ferritin showed reduced values. The results indicate that individuals who are ordered cell blood count (CBC) measures alone without examining the indicators of iron status (Group C vs Group D) may not be correctly assessed with a definitive diagnosis and categorized as normal individuals. But in fact, they are susceptible to iron depletion and could develop iron deficiency anemia.

CONCLUSIONS

In evaluation of iron deficiency status it is important that total CBC test be accompanied by the other tests of iron status to pinpoint true iron deficiency. Otherwise, many cases may be missed out and misdiagnosed as normal individuals.

Iron deficiency with normal ferritin levels in restless legs syndrome

This report describes a patient with iron deficiency in bone marrow examination and iron-responsive restless legs syndrome (RLS), in whom serum ferritin levels were well above the conventional cutoff for considering iron deficiency. The predictive value of serum ferritin for iron deficiency in RLS depends on the cutoff employed, on the pre-test likelihood of iron deficiency and on coexisting inflammatory conditions. Bone marrow examination is helpful when ferritin levels are equivocal.

Iron regulatory protein 1 as a sensor of reactive oxygen species

Iron regulatory proteins (IRP1 and 2) function as translational regulators that coordinate the cellular iron metabolism of eukaryotes by binding to the mRNA of target genes such as the transferrin receptor or ferritin. In addition to IRP2, IRP1 serves as sensor of reactive oxygen species (ROS). As iron and oxygen are essential but potentially toxic constituents of most organisms, ROS-mediated modulation of IRP1 activity may be an important regulatory element in dissecting iron homeostasis and oxidative stress. The responses of IRP1 towards reactive oxygen species are compartment-specific and rather complex: H2O2 activates IRP1 via a signaling cascade that leads to upregulation of the transferrin receptor and cellular iron accumulation. Contrary, superoxide inactivates IRP1 by a direct chemical attack being limited to the intracellular compartment. In particular, activation of IRP1 by H2O2 has established a new regulatory link between inflammation and iron metabolism with new clinical implications. This mechanism seems to contribute to the anemia of chronic disease and inflammation-mediated iron accumulation in tissues. In addition, the cytotoxic side effects of redox-cycling anticancer drugs such as doxorubicin may involve H2O2-mediated IRP1 activation. These molecular insights open up new therapeutic strategies for the clinical management of chronic inflammation and drug-mediated cardiotoxicity.

Iron assessment tests: transferrin receptor vis-à-vis zinc protoporphyrin

OBJECTIVES

To review and compare the biochemical, analytical, and clinical features of two relatively new tests for assessing iron status and diagnosing iron disorders, namely, the serum transferrin receptor concentration (sTfR) and the erythrocyte zinc protoporphyrin/heme ratio (ZnPP/H). To consider the merits of each test for the diagnosis of iron disorders with emphasis on iron-deficient erythropoiesis, especially in the clinically important preanemia stage of iron depletion.

CONCLUSIONS

Although the basic biochemical mechanisms underlying the two tests are very different, both of these tests are noteworthy because they are considered to reflect iron status in the bone marrow. The principal advantage to serum transferrin receptor is the lack of a response to anemia of chronic disease (ACD), which affects other iron status indicators, for example, ferritin and transferrin saturation. The principal advantage to erythrocyte zinc protoporphyrin is low cost, but point-of-care testing and simplicity can also be advantages. Both serum transferrin receptor and erythrocyte zinc protoporphyrin have been demonstrated to be useful in a variety of clinical situations. Serum transferrin receptor can be best used in diagnosing iron disorders, especially for patients with pathologies that may affect iron metabolism. Erythrocyte zinc protoporphyrin can be best used as a primary screening test for assessing iron status, especially in patients likely to have uncomplicated iron deficiency. While these applications are primary, both tests are more broadly useful, for example, in monitoring iron therapy.

Mechanisms of Unexplained Anemia in the Nursing Home

OBJECTIVES

To characterize anemia in elderly nursing home residents.

DESIGN

Prospective multiinstitutional cohort study.

SETTING

Five nursing homes.

PARTICIPANTS

From retrospective analysis, residents found to be anemic using chart review were prospectively randomized. Of the 81 residents enrolled, 60 were anemic.

MEASUREMENTS

Chart review for medical history and factors related to treatment or history of anemia, extensive laboratory evaluation for causes of anemia, and classification of anemia by two hematologists.

RESULTS

Among the 60 anemic residents, the causes of anemia were idiopathic (n=27), iron-deficiency (n=14), anemia associated with chronic disease (n=8), anemia of renal insufficiency (n=6), and other (n=5). The eryrthropoietin (EPO) response to anemia was lower in residents with idiopathic anemia (IA) than in those with iron-deficiency anemia, and this correlated with renal function as estimated using calculated creatinine clearance. In this elderly population, advancing age was not correlated with lower EPO response.

CONCLUSION

IA is common in nursing home residents. A lower EPO response contributes to the high prevalence of anemia in this setting and may be due, in part, to occult renal dysfunction.

Strategies for the Laboratory Diagnosis of Some Common Causes of Anaemia in Elderly Patients

Anaemia is a common medical problem in elderly patients and is associated with an increased mortality and morbidity risk and a reduced quality of life. It is not known at which exact haemoglobin level investigations should be initiated in order to optimize the diagnostic efficacy. Serum ferritin determination remains the most accurate laboratory test for the diagnosis of iron deficiency anaemia and its differential diagnosis with the anaemia of chronic disease. The introduction of the metabolites methylmalonic acid and homocysteine has made it possible to diagnose vitamin B(12) and folate deficiencies at an early subclinical stage, even without neurological and haematological symptoms, but the clinical importance of this 'biochemical' diagnosis is unclear. Other causes of anaemia, such as myelodysplastic syndromes and chronic renal insufficiency, will become more and more common in the elderly because of the ageing of the population. Although erythropoietin analysis has no clear diagnostic value at the moment, it has become more and more obvious that its therapeutic importance in elderly patients with chronic anaemia is increasing. A substantial number of patients have an unexplained anaemia. Whether this is disease related, or may be attributed to an age-related anaemia, is still a matter of debate, but it is advisable to perform an extensive laboratory, cytogenetic, and morphological investigation before one should assess the anaemia as unexplained.

Soluble Transferrin Receptor and Soluble Transferrin Receptor-Ferritin Index for Evaluation of the Iron Status in Elderly Patients

We aimed to evaluate the diagnostic values of soluble transferrin receptor (sTfR) concentration, transferrin-ferritin index (soluble transferrin receptor concentration/log ferritin), ferritin levels and other related parameters in geriatric patients with anemia of chronic disease (ACD) and iron deficiency (IDA). Forty-four elderly subjects (median age 73 [63-94]) and twenty healthy subjects (median age 49 [44-56]) were enrolled into this study, divided into four groups: twenty middle aged healthy subjects (group A), fifteen elderly patients with IDA (group B), fourteen elderly patients with ACD (group C) and fifteen nonanemic geriatric subjects (group D). Hemoglobin, mean corpuscular volume, serum iron concentration and transferrin saturation levels of the patients in IDA group were found significantly lower than those in both non-anemic group and healthy subjects. Serum sTfR concentrations of the patients in IDA group were significantly higher than those in non-anemic geriatric group, ACD group and healthy subjects. Transferrin-ferritin index of the patients with IDA was significantly higher than that in non-anemic geriatric and ACD group. Serum ferritin levels of the patients in IDA group did not show any differences when compared with the other groups. Serum ferritin was highly specific for IDA (95%) when compared with ACD, although its sensitivity was low (38%). STfR values were negatively correlated with both transferrin and ferritin levels (p = 0.042 r = -0.40; and p = 0.034 r = -0.41, respectively). In conclusion, serum soluble transferrin receptor and transferrin-ferritin index may be used together with serum ferritin to distinguish the iron deficiency state in the elderly.

Prospective evaluation of a clinical guideline for the diagnosis and management of iron deficiency anemia

PURPOSE

We examined the effect of introducing an evidence-based clinical guideline on the diagnosis and evaluation of iron deficiency anemia.

SUBJECTS AND METHODS

The guideline recommended measurement of serum ferritin levels for all anemic patients with a mean corpuscular volume (MCV) </=95 fL and endoscopic evaluation for those with a serum ferritin level less than 45 ng/mL. Physicians practicing in the general medicine inpatient and outpatient services of two university-affiliated hospitals were informed about the guideline and the data supporting it. Clinical evaluations during the 9 months before ("control period," n = 3341 patients) and the 9 months after ("intervention period," n = 3173 patients) the introduction of the guideline were compared.

RESULTS

There was a 30% increase (95% confidence interval [CI]: 22% to 39%) in the proportion of anemic patients who underwent serum ferritin evaluation in the intervention period (41% [n = 1284]) compared with in the control period (31% [n = 1040]), and a 24% increase (95% CI: 4% to 48%) in the proportion with a serum ferritin level <45 ng/mL (8.1% [n = 256] vs. 6.5% [n = 217]). The proportion of anemic patients who underwent endoscopic evaluation within 4 months of measurement of low serum ferritin level in the intervention period (3.3% [n = 106]) was 67% higher (95% CI: 23% to 125%) than in the control period (2.0% [n = 67]), and the proportion with serious gastrointestinal lesions found as a result of endoscopy was 62% (95% CI: 8% to 145%) higher (1.8% [n = 57] vs. 1.1% [n = 37]).

CONCLUSIONS

Introduction of a guideline describing appropriate evaluation of iron deficiency anemia led to an increase in the proportions of patients evaluated for iron deficiency anemia and found to have serious gastrointestinal lesions.