The Significance of iron deficiency and anemia in a real-life COPD cohort

Predictors of Success of Inpatient Pulmonary Rehabilitation Program in COPD Patients

Purpose

Pulmonary rehabilitation programs (PR) are an important part of the comprehensive treatment of patients with chronic pulmonary diseases. Patients respond individually to PR. The aim of this study is to identify potential predictors of success of PR to recognise patients who benefit most and to uncover possible reasons for poor response to PR.

Patients and Methods

We included 121 patients with chronic obstructive pulmonary disease (COPD) who completed our 4-week inpatient PR without any exacerbations of disease during PR that could potentially affect PR outcomes. Improvement in distance of ≥30 m on the 6-minute walk test (6MWT) after PR was chosen as a primary marker of physical success. Ninety-one patients achieved improvement of ≥30 m on the 6MWT and were thus considered good responders, and 30 patients were poor responders with improvement in the distance of <30 m on the 6MWT.

Results

We compared baseline clinical characteristics, medication, lung function, physical capacity, body composition, and laboratory blood tests between groups of good and poor responders. The most prominent differences between groups were associated with differences in baseline body composition and erythrocyte-related parameters. Good responders had significantly lower body water content (p = 0.042) and higher body weight (p = 0.036), body fat content (p = 0.049), dry lean mass (p = 0.021), haemoglobin levels (p = 0.040), erythrocyte count (p = 0.017), haematocrit (p = 0.030) and iron level (p = 0.028).

Conclusion

A more muscular body composition and a higher ability to transport oxygen from the blood to the muscles could be beneficial for the outcome of PR.

Causal association between iron deficiency anemia and chronic obstructive pulmonary disease: A bidirectional two-sample Mendelian randomization study

BACKGROUND

Observational studies have found an association between iron deficiency anemia (IDA) and chronic obstructive pulmonary disease (COPD) risk. However, whether IDA plays a role in COPD development remains unclear.

OBJECTIVES

This study was performed to explore the causal association between IDA and COPD.

METHODS

We obtained summary statistics for IDA from 6087 cases and 211,115 controls of European ancestry in an open genome-wide association study (GWAS) to select strongly associated single nucleotide polymorphisms that could serve as instrumental variables for IDA (P < 5 × 10-8). Additional summary statistics for COPD were obtained from 6915 COPD cases and 186,723 controls of European ancestry from a publicly available GWAS. A bidirectional Mendelian randomization analysis was performed using inverse variance weighting as the primary method of analysis. The reliability of the results was verified by heterogeneity and sensitivity analysis.

RESULTS

IDA increased the risk of COPD, with an odds ratio (OR) of 1.15 (95% confidence interval (CI: 1.04-1.25, p = 0.002). There was no evidence of a causal effect of COPD on IDA risk, with an OR of 0.99 (95% CI: 0.87-1.13, p = 0.91). The sensitivity analysis showed no evidence of heterogeneity or horizontal pleiotropy.

CONCLUSIONS

We found that IDA increases the risk of COPD. Additionally, there was no evidence that COPD increases the risk of IDA. Therefore, IDA should be considered in future COPD risk studies and reintroduced as a potential therapeutic target. The relationship between COPD and IDA risk requires further study using indirect mechanisms.

The role of iron in chronic inflammatory diseases: from mechanisms to treatment options in anemia of inflammation

Anemia of inflammation (AI) is a highly prevalent comorbidity in patients affected by chronic inflammatory disorders, such as chronic kidney disease, inflammatory bowel disease, or cancer, that negatively affect disease outcome and quality of life. The pathophysiology of AI is multifactorial, with inflammatory hypoferremia and iron-restricted erythropoiesis playing a major role in the context of disease-specific factors. Here, we review the recent progress in our understanding of the molecular mechanisms contributing to iron dysregulation in AI, the impact of hypoferremia and anemia on the course of the underlying disease, and (novel) therapeutic strategies applied to treat AI.

Influence of SERPINA1 Gene Polymorphisms on Anemia and Chronic Obstructive Pulmonary Disease

BACKGROUND

Anemia is one of the predominant hematological conditions, whereas chronic obstructive pulmonary disease (COPD) is a predominant respiratory disease. These two diseases were found to be interlinked, but the physiological pathways are still unclear.

AIM

The current study has been aimed at analysing the genetic interrelationship between anemia and COPD in accordance with different altitudes. Methodology. The genetic analysis was performed in the SERPINA1 gene of anemia, COPD, and healthy individuals for the analysis of single nucleotide polymorphism at rs28949274 and rs17580 locations. Result and Discussion. The single nucleotide polymorphism at the locations rs28949274 and rs17580 was present in both anemic and COPD patients. The COPD patients were more prone to mutations (63% had rs28949274, and 11% had rs17580 polymorphisms) than the anemic patients (40% had rs28949274, and 1% had rs17580 polymorphisms). On the basis of altitude, high-altitude individuals were found to be more susceptible to both the polymorphisms.

CONCLUSION

Based on the current findings, we suggest that the SERPINA1 gene has a positive correlation with anemia as well as COPD, and the increase in altitude also influences the diseased conditions in a positive manner.

Iron Depletion in Systemic and Muscle Compartments Defines a Specific Phenotype of Severe COPD in Female and Male Patients: Implications in Exercise Tolerance

We hypothesized that iron content and regulatory factors, which may be involved in exercise tolerance, are differentially expressed in systemic and muscle compartments in iron deficient severe chronic obstructive pulmonary disease (COPD) patients. In the vastus lateralis and blood of severe COPD patients with/without iron depletion, iron content and regulators, exercise capacity, and muscle function were evaluated in 40 severe COPD patients: non-iron deficiency (NID) and iron deficiency (ID) (20 patients/group). In ID compared to NID patients, exercise capacity, muscle iron and ferritin content, serum transferrin saturation, hepcidin-25, and hemojuvelin decreased, while serum transferrin and soluble transferrin receptor and muscle IRP-1 and IRP-2 increased. Among all COPD, a significant positive correlation was detected between FEV₁ and serum transferrin saturation. In ID patients, significant positive correlations were detected between serum ferritin, hepcidin, and muscle iron content and exercise tolerance and between muscle IRP-2 and serum ferritin and hepcidin levels. In ID severe COPD patients, iron content and its regulators are differentially expressed. A potential crosstalk between systemic and muscle compartments was observed in the ID patients. Lung function and exercise capacity were associated with several markers of iron metabolism regulation. Iron status should be included in the overall assessment of COPD patients given its implications in their exercise performance.

Pulmonary Arterial Pressure Changes Under Dobutamine Stress Echocardiography in Non-Anemic Iron Deficient COPD Subjects

Purpose

Non-anemic iron deficiency (NAID) is common in COPD, and could induce functional/structural changes in the pulmonary vascular bed. Thus, we aimed to study, during resting and ambient oxygen conditions, the systolic pulmonary arterial pressure (sPAP) changes during dobutamine stress echocardiography (DSE) for NAID+ compared to NAID- subjects with COPD.

Patients and Methods

We analyzed 24 patients with COPD and evaluated their clinical parameters, including lung function and serum iron profile, followed by the changes in the sPAP under DSE.

Results

Ten subjects with NAID+ were compared with fourteen NAID- subjects for sPAP measurement. At baseline, only left atrial volume was significantly different between groups (30±4 vs 23±5 mL_*m²), respectively (p-value=0.002). For the right side, tricuspid annular plane systolic excursion (TAPSE) was similar between-groups (22±2 vs 20±4, p-value >0.05), at baseline. The sPAP (mmHg) changes were also not significantly different between groups (pre 32±14 vs peak 48±14 for NAID+ and pre 29±7 vs peak 43±10 for NAID-, Group p-value=0.400, Time p-value <0.0001, and Interaction p-value=0.606).

Conclusion

COPD subjects with NAID do not show increased sPAP responses during DSE, compared with iron-replete subjects.

Anemia in chronic obstructive pulmonary disease: A systematic review

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a type of obstructive lung disease that is characterized by poor airflow and airway inflammation. It is estimated that the global prevalence of COPD is about 13.1%. Anemia is associated with increased morbidity and hospitalization duration. In this systematic review, we investigate the association between all types of anemia and COPD progression.

METHODS

We systematically searched electronic databases, including Scopus, Medline/PubMed, EMBASE, Web of Sciences (WOS), and Cochrane Library, using the following mesh-standardized keywords: (((anemia∗ OR anaemia∗) OR "chronic anemia disease" [Mesh] OR "CAD" OR "iron deficiency anemia" OR" IDA" OR) AND ("COPD" [Mesh] OR "chronic obstructive pulmonary disease")) until February 2022.

RESULTS

Overall of 11,158 studies were included. Ultimately, 59 studies were included in the analysis. The most apparent findings from the analysis were that exacerbation of COPD, increased hospitalization, and increased long-term mortality were associated with anemia. Further analysis showed that iron deficiency (ID) is a common finding in COPD and is accompanied by an increase in the systolic pulmonary artery pressure.

CONCLUSION

Despite the comfortable control of anemia, the absence of treatment can be life-threatening in patients with COPD. Our systematic results showed significant homogeneity between studies on the increased mortality rate in anemic COPD, increased hospitalization, and decreased quality of life.

The Relationship between Serum Uric Acid Levels and Early Mortality in Chronic Obstructive Pulmonary Disease Cases during Exacerbation

AIM

In this study, it was aimed to compare the levels of serum uric acid and uric acid/creatinine ratios in patients with COPD during an attack or in stable COPD, and to show whether serum uric acid and uric acid/creatinine ratios are associated with early mortality in COPD patients during an acute attack.

MATERIALS AND METHODS

In this study, COPD acute attack (n=155) and stable COPD (n=30) patients were evaluated. The data of these patients were obtained from patient files and computer records. COPD diagnosis and severity assessment were made according to the GOLD 2006 guideline. Participants' age, gender, body mass index, pulmonary function test, arterial blood gas, uric acid, creatinine values and comorbidity information were recorded in the previously prepared Case Data Form. In 2012, when we conducted this study, gold 2006 was taken as the guideline for spirometry measurement, but spirometric measurements determined with reference values determined according to age, height and gender, and FEV1/FVC measurement <70% as diagnostic criteria in acute attack after bronchodilator were the guidelines used later, gold 2017. It is also compatible with gold2020 and gold2021 spirometry criteria.

RESULTS

It was determined that the uric acid (p<0.001) and uric acid/creatinine (p<0.001) levels of the patients in the acute attack group were significantly higher than the levels of the patients in the stable group. The attack group was divided into two subgroups according to certain cut-off points for uric acid (>6 mg/dl for women and >7 mg/dl for men) and uric acid/creatinine ratio (median value 7.10). Since the upper limit of the uric acid value measured in the blood is 6 mg/dl in women and 7-8 mg/dl in men, the cut-off points for uric acid (>6 mg/dl for women and >7 mg/dl for men) were determined in our study. According to this categorization, it was determined that there was no statistically significant relationship between uric acid level (odds ratio 2.985 [95% confidence interval 0.61814,151]) and early mortality risk.

CONCLUSION

The results of this study showed that the uric acid and uric acid/creatinine levels in the attack group were higher than the levels in the stable group, but these parameters were not associated with early mortality.

Iron-Deficiency in Atopic Diseases: Innate Immune Priming by Allergens and Siderophores

Although iron is one of the most abundant elements on earth, about a third of the world's population are affected by iron deficiency. Main drivers of iron deficiency are beside the chronic lack of dietary iron, a hampered uptake machinery as a result of immune activation. Macrophages are the principal cells distributing iron in the human body with their iron restriction skewing these cells to a more pro-inflammatory state. Consequently, iron deficiency has a pronounced impact on immune cells, favoring Th2-cell survival, immunoglobulin class switching and primes mast cells for degranulation. Iron deficiency during pregnancy increases the risk of atopic diseases in children, while both children and adults with allergy are more likely to have anemia. In contrast, an improved iron status seems to protect against allergy development. Here, the most important interconnections between iron metabolism and allergies, the effect of iron deprivation on distinct immune cell types, as well as the pathophysiology in atopic diseases are summarized. Although the main focus will be humans, we also compare them with innate defense and iron sequestration strategies of microbes, given, particularly, attention to catechol-siderophores. Similarly, the defense and nutritional strategies in plants with their inducible systemic acquired resistance by salicylic acid, which further leads to synthesis of flavonoids as well as pathogenesis-related proteins, will be elaborated as both are very important for understanding the etiology of allergic diseases. Many allergens, such as lipocalins and the pathogenesis-related proteins, are able to bind iron and either deprive or supply iron to immune cells. Thus, a locally induced iron deficiency will result in immune activation and allergic sensitization. However, the same proteins such as the whey protein beta-lactoglobulin can also transport this precious micronutrient to the host immune cells (holoBLG) and hinder their activation, promoting tolerance and protecting against allergy. Since 2019, several clinical trials have also been conducted in allergic subjects using holoBLG as a food for special medical purposes, leading to a reduction in the allergic symptom burden. Supplementation with nutrient-carrying lipocalin proteins can circumvent the mucosal block and nourish selectively immune cells, therefore representing a new dietary and causative approach to compensate for functional iron deficiency in allergy sufferers.

Iron deficiency is related to low functional outcome in patients at early rehabilitation after acute stroke

BACKGROUND

Iron deficiency (ID) is a common co-morbidity in patients with cardiovascular disease and contributes to impaired functional capacity. The relevance of ID in patients in recovery after acute stroke is not known. We assessed the prevalence of ID and anaemia in relation to functional capacity and to recovery during early rehabilitation after stroke.

METHODS

This observational study enrolled consecutively 746 patients with ischaemic or haemorrhagic stroke at in-patient early rehabilitation (age 68 ± 13 years, female 47%, ischaemic stroke 87%). Functional capacity was assessed before and after rehabilitation using Barthel index (reha-BI), motricity index (MI), trunk control test (TCT), and functional ambulatory category (FAC). ID was defined as ferritin <100 μg/L or as transferrin saturation (TSAT) < 20% if ferritin was 100- < 300 μg/L or if CrP > 5 mg/L. Anaemia was defined as Hb < 12 g/dL (women) and <13 g/dL (men).

RESULTS

The prevalence of ID and anaemia before rehabilitation were 45% and 46%, respectively, and remained high at discharge (after 27 ± 17 days) at 40% and 48%, respectively. Patients with ID had lower functional capacity compared with patients without ID (reha-BI 20 [±86] vs. 40 [±80], MI 64 [±66] vs. 77 [±41], TCT 61 [±76] vs. 100 [±39], FAC 1 [±4] vs. 4 [±4]; median [IQR], all P < 0.001). ID was related to inflammation (OR 2.68 [95% CI 1.98-3.63], P < 0.001), female sex (OR 2.13 [95% CI 1.59-2.85], P < 0.001), haemorrhagic stroke (OR 1.70 [95% CI 1.11-2.61], P = 0.015), initial treatment on stroke unit (OR 3.59 [95% CI 1.08-11.89], P < 0.001), and anaemia (OR 2.94 [95% CI 2.18-3.96], P < 0.001), while age, BMI, and renal function were not related to ID. In adjusted analysis, ID was associated with low functional capacity in all functional scores: reha-BI (OR 1.66 [95% CI 1.08-2.54], P = 0.02), motricity index (OR 1.94 [95% CI 1.36-2.76], P < 0.001), trunk control test (OR 2.34 [95% CI] 1.64-3.32, P < 0.001) and functional ambulatory category (OR 1.77 [95% CI 1.2-2.63], P < 0.02). Functional capacity improved during rehabilitation regardless of presence of ID, but functional outcome remained significantly lower in patients with ID at the end of rehabilitation (rehab BI and MI, both P < 0.001).

CONCLUSIONS

Iron deficiency and anaemia are common and persistent findings in patients after acute stroke. ID and anaemia are independently related to lower functional capacity after acute stroke and to poor functional outcome after rehabilitation. Regular assessment of iron status may identify patients at risk of low functional recovery.

Ameliorating Atopy by Compensating Micronutritional Deficiencies in Immune Cells: A Double-Blind Placebo-Controlled Pilot Study

BACKGROUND

Functional iron deficiency facilitates allergy development and amplifies the symptom burden in people experiencing allergies. Previously we selectively delivered micronutrients to immune cells with β-lactoglobulin as carrier (holoBLG), resulting in immune resilience and allergy prevention.

OBJECTIVE

The clinical efficacy of a food for special medical purposes-lozenge containing β-lactoglobulin with iron, polyphenols, retinoic acid, and zinc (holoBLG lozenge) was assessed in allergic women.

METHODS

In a randomized, double-blind, placebo-controlled pilot study, grass- and/or birch pollen-allergic women (n = 51) were given holoBLG or placebo lozenges over 6 months. Before and after dietary supplementation, participants were nasally challenged and the blood was analyzed for immune and iron parameters. Daily symptoms, medications, pollen concentrations, and well-being were recorded by an electronic health application.

RESULTS

Total nasal symptom score after nasal provocations improved by 42% in the holoBLG group versus 13% in the placebo group. The combined symptom medication score during the birch peak and entire season as well as the entire grass pollen season improved in allergic subjects supplemented with the holoBLG lozenge by 45%, 31%, and 40%, respectively, compared with the placebo arm. Participants ingesting the holoBLG lozenge had improved iron status with increased hematocrit values, decreased red cell distribution width, and higher iron levels in circulating CD14⁺ cells compared with the placebo group.

CONCLUSIONS

Targeted micronutrition with the holoBLG lozenge seemed to be effective in elevating the labile iron levels in immune cells and reducing the symptom burden in allergic women in this pilot study. The underlying allergen-independent mechanism provides evidence that dietary nutritional supplementation of the immune system is one of the ways to combat atopy.

Physiology and Inflammation Driven Pathophysiology of Iron Homeostasis-Mechanistic Insights into Anemia of Inflammation and Its Treatment

Anemia is very common in patients with inflammatory disorders. Its prevalence is associated with severity of the underlying disease, and it negatively affects quality of life and cardio-vascular performance of patients. Anemia of inflammation (AI) is caused by disturbances of iron metabolism resulting in iron retention within macrophages, a reduced erythrocyte half-life, and cytokine mediated inhibition of erythropoietin function and erythroid progenitor cell differentiation. AI is mostly mild to moderate, normochromic and normocytic, and characterized by low circulating iron, but normal and increased levels of the storage protein ferritin and the iron hormone hepcidin. The primary therapeutic approach for AI is treatment of the underlying inflammatory disease which mostly results in normalization of hemoglobin levels over time unless other pathologies such as vitamin deficiencies, true iron deficiency on the basis of bleeding episodes, or renal insufficiency are present. If the underlying disease and/or anemia are not resolved, iron supplementation therapy and/or treatment with erythropoietin stimulating agents may be considered whereas blood transfusions are an emergency treatment for life-threatening anemia. New treatments with hepcidin-modifying strategies and stabilizers of hypoxia inducible factors emerge but their therapeutic efficacy for treatment of AI in ill patients needs to be evaluated in clinical trials.

Nutrition as a modifiable factor in the onset and progression of pulmonary function impairment in COPD: a systematic review

CONTEXT

Chronic obstructive lung disease (COPD) is a progressive lung disease characterized by persistent airflow limitation. An increasing amount of evidence suggests an effect of dietary quality on the risk of COPD in the general population and pulmonary function decline in patients with COPD.

OBJECTIVE

The association of dietary intake and nutrient status with COPD risk and onset, as well as pulmonary function decline (change in forced expiratory volume in 1 second, forced vital capacity, or the ratio of the former to the latter) in patients with COPD was investigated in this systematic review.

DATA SOURCES

The PubMed database was searched by combining terms of pulmonary function or COPD with diet, nutrient status, or nutritional supplementation.

DATA EXTRACTION

Original studies and systematic reviews and meta-analyses were included. Articles obtained were independently screened for relevance on the bases of title and abstract by 2 researchers. Eventually, 89 articles were included in the analysis.

RESULTS

The unhealthy Western-style diet is associated with an increased risk of COPD and an accelerated decline of pulmonary function. Intake of fruit, vegetables, dietary fibers, vitamins C and E, polyphenols, and β-carotene were individually associated with lower COPD risk, whereas consumption of processed meat was associated with higher COPD risk. Data on the effect of dietary quality on pulmonary function decline in patients with COPD are limited and inconsistent. Strong evidence for beneficial effects on pulmonary function decline was found only for vitamin D supplementation.

CONCLUSION

Considering the increasing burden of COPD, more attention should be given to dietary quality as a modifiable factor in disease development and progression in patients with COPD.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021240183.

Iron Replacement and Redox Balance in Non-Anemic and Mildly Anemic Iron Deficiency COPD Patients: Insights from a Clinical Trial

In COPD patients, non-anemic iron deficiency (NAID) is a common systemic manifestation. We hypothesized that in COPD patients with NAID, iron therapy may improve systemic oxidative stress. The FACE (Ferinject assessment in patients with COPD and iron deficiency to improve exercise tolerance) study was a single-blind, unicentric, parallel-group, placebo-controlled clinical trial (trial registry: 2016-001238-89). Sixty-six patients were enrolled (randomization 2:1): iron arm, n = 44 and placebo arm, n = 22, with similar clinical characteristics. Serum levels of 3-nitrotyrosine, MDA-protein adducts, and reactive carbonyls, catalase, superoxide dismutase (SOD), glutathione, Trolox equivalent antioxidant capacity (TEAC), and iron metabolism biomarkers were quantified in both groups. In the iron-treated patients compared to placebo, MDA-protein adducts and 3-nitrotyrosine serum levels significantly declined, while those of GSH increased and iron metabolism parameters significantly improved. Hepcidin was associated with iron status parameters. This randomized clinical trial evidenced that iron replacement elicited a decline in serum oxidative stress markers along with an improvement in GSH levels in patients with stable severe COPD. Hepcidin may be a surrogate biomarker of iron status and metabolism in patients with chronic respiratory diseases. These findings have potential clinical implications in the management of patients with severe COPD.

The associations between red cell distribution width and lung function measures in a general population

BACKGROUND

Red cell distribution width (RDW) reflects heterogeneity of the erythrocyte volumes. High RDW is a novel risk marker, which has been associated with mortality and morbidity both from cardiovascular and respiratory diseases, but the association between RDW and measures of lung function in the general population remains unclear.

METHODS

The associations of RDW with spirometry, diffusing capacity (D_LCO) and impulse oscillometry (IOS) were investigated among 5767, 5496 and 5598 subjects (aged 50-64 years), respectively, from the Swedish CArdioPulmonary bioImage Study (SCAPIS). Multiple linear regression and general linear models were performed to examine the relationships of lung function measures and RDW, with adjustment for potential confounding factors.

RESULTS

Forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC) and FEV₁/FVC were significantly and inversely associated with RDW after multivariate adjustments. For 1- standard deviation (SD) increase in RDW, FEV₁ decreased with 0.034 L (95%CI: -0.046 to -0.022 L), p < 0.001; FVC with 0.031 L (95%CI: -0.045 to -0.017 L), p < 0.001; and FEV₁/FVC with 0.003 (95%CI: -0.004 to -0.001), p = 0.002. Significant associations of RDW and D_LCO were only found among smokers. For IOS, pulmonary reactance rather than resistance was significantly associated with RDW: X₅ decreased 0.002 kPa/(L/s) (95%CI: -0.003 to -0.0002 kPa/(L/s)), p = 0.025, per 1-SD higher RDW.

CONCLUSIONS

We found significant negative associations between RDW and measures of lung function. However, the effect sizes are small and RDW is not likely to be a sensitive marker of impaired lung function in middle-aged individuals from the general population.