Anemia is Associated with Bone Mineral Density in Chronic Obstructive Pulmonary Disease

Progress in research on osteoporosis secondary to SARS-CoV-2 infection

The World Health Organization has declared that COVID-19 no longer constitutes a "public health emergency of international concern," yet the long-term impact of SARS-CoV-2 infection on bone health continues to pose new challenges for global public health. In recent years, numerous animal model and clinical studies have revealed that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can lead to secondary osteoporosis. The mechanisms involved are related to the virus's direct effects on bone tissue, dysregulation of the body's inflammatory response, hypoxia, noncoding RNA imbalance, and metabolic abnormalities. Although these studies have unveiled the connection between SARS-CoV-2 infection and osteoporosis, current research is not comprehensive and in depth. Future studies are needed to evaluate the long-term effects of SARS-CoV-2 on bone density and metabolism, elucidate the specific mechanisms of pathogenesis, and explore potential interventions. This review aims to collate existing research literature on SARS-CoV-2 infection-induced secondary osteoporosis, summarize the underlying mechanisms, and provide direction for future research.

Exploring the pathophysiology of anemia in COPD: Insights from chest CT and longitudinal clinical data

BACKGROUND

Although anemia has been associated with chronic obstructive pulmonary disease (COPD) severity, the underlying risk factors, such as chest imaging indicators, remain poorly understood. In this study, we aimed to investigate the relationship between anemia and clinical features, including pulmonary and extrapulmonary indicators on chest computed tomography (CT), and to clarify the pathophysiology of anemia in COPD.

METHODS

A total of 400 patients with COPD were prospectively followed for 3 years. Anemia was defined as hemoglobin <13 g/dl in males and <12 g/dl in females. Patients were categorized into the anemia and non-anemia groups, and their clinical characteristics were compared.

RESULTS

The anemia group exhibited lower percentage of predicted forced expiratory volume in 1 s (%FEV1) and body mass index (BMI) measurements, worse COPD assessment test (CAT) scores, and more frequent exacerbations. Imaging revealed more severe emphysema, lower cross-sectional areas of the pectoralis and erector spinae muscles, decreased subcutaneous fat, and more severe coronary artery calcification in this group. Additionally, echocardiography demonstrated a higher prevalence of pulmonary hypertension and reduced left ventricular ejection fraction in patients with anemia. Three-year longitudinal data analysis further showed that declining hemoglobin levels correlated with the worsening of nutritional status, a deterioration in bone mineral density (BMD), and an increase in CAT scores.

CONCLUSION

Anemia in COPD is a multifactorial comorbidity resulting in emphysema, decreased fat and muscle mass, and reduced BMD.

SARS-CoV-2 and its Multifaceted Impact on Bone Health: Mechanisms and Clinical Evidence

PURPOSE OF REVIEW

SARS-CoV-2 infection, the culprit of the COVID-19 pandemic, has been associated with significant long-term effects on various organ systems, including bone health. This review explores the current understanding of the impacts of SARS-CoV-2 infection on bone health and its potential long-term consequences.

RECENT FINDINGS

As part of the post-acute sequelae of SARS-CoV-2 infection, bone health changes are affected by COVID-19 both directly and indirectly, with multiple potential mechanisms and risk factors involved. In vitro and preclinical studies suggest that SARS-CoV-2 may directly infect bone marrow cells, leading to alterations in bone structure and osteoclast numbers. The virus can also trigger a robust inflammatory response, often referred to as a "cytokine storm", which can stimulate osteoclast activity and contribute to bone loss. Clinical evidence suggests that SARS-CoV-2 may lead to hypocalcemia, altered bone turnover markers, and a high prevalence of vertebral fractures. Furthermore, disease severity has been correlated with a decrease in bone mineral density. Indirect effects of SARS-CoV-2 on bone health, mediated through muscle weakness, mechanical unloading, nutritional deficiencies, and corticosteroid use, also contribute to the long-term consequences. The interplay of concurrent conditions such as diabetes, obesity, and kidney dysfunction with SARS-CoV-2 infection further complicates the disease's impact on bone health. SARS-CoV-2 infection directly and indirectly affects bone health, leading to potential long-term consequences. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

COVID-19 and Bone Loss: A Review of Risk Factors, Mechanisms, and Future Directions

PURPOSE OF REVIEW

SARS-CoV-2 drove the catastrophic global phenomenon of the COVID-19 pandemic resulting in a multitude of systemic health issues, including bone loss. The purpose of this review is to summarize recent findings related to bone loss and potential mechanisms.

RECENT FINDINGS

The early clinical evidence indicates an increase in vertebral fractures, hypocalcemia, vitamin D deficiencies, and a loss in BMD among COVID-19 patients. Additionally, lower BMD is associated with more severe SARS-CoV-2 infection. Preclinical models have shown bone loss and increased osteoclastogenesis. The bone loss associated with SARS-CoV-2 infection could be the result of many factors that directly affect the bone such as higher inflammation, activation of the NLRP3 inflammasome, recruitment of Th17 cells, the hypoxic environment, and changes in RANKL/OPG signaling. Additionally, SARS-CoV-2 infection can exert indirect effects on the skeleton, as mechanical unloading may occur with severe disease (e.g., bed rest) or with BMI loss and muscle wasting that has also been shown to occur with SARS-CoV-2 infection. Muscle wasting can also cause systemic issues that may influence the bone. Medications used to treat SARS-CoV-2 infection also have a negative effect on the bone. Lastly, SARS-CoV-2 infection may also worsen conditions such as diabetes and negatively affect kidney function, all of which could contribute to bone loss and increased fracture risk. SARS-CoV-2 can negatively affect the bone through multiple direct and indirect mechanisms. Future work will be needed to determine what patient populations are at risk of COVID-19-related increases in fracture risk, the mechanisms behind bone loss, and therapeutic options. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

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.

Association of hemoglobin levels with bone mineral density for adults over 18 years of age: a cross-sectional study

The overall objective of this study was to determine the association between hemoglobin (HGB) and bone mineral density (BMD) in the lumbar and thoracic spine of adults aged ≥ 18 years. This cross-sectional study utilized the non-institutionalized US population from the National Health and Nutrition Survey (NHANES) as the sample source. A multiple linear regression model was used to assess the relationship between HGB and BMD in the lumbar and thoracic spine, with analysis of subgroups conducted according to sex and race. Smooth curve fitting was performed to explore the potential nonlinear relationship. When nonlinearity was found, we further constructed a weighted two-piecewise linear regression model and used a recursive algorithm to calculate the inflection point. After accounting for relevant confounding variables, HGB was found to be negatively associated with lumbar spine BMD in multiple regression models. However, in the subgroup analyses stratified by sex and race, the relationship between HGB and thoracic spine BMD and lumbar spine BMD was only found in women and other races and races that were not recorded. In Non-Hispanic Asian subjects, the relationship between HGB and BMD in the lumbar spine and thoracic spine showed a U-shaped curve. In addition, the relationship between HGB and BMD in the lumbar spine formed an inverted U-shaped curve among participants in other races and those whose race was not reported. Our study shows that HGB has a non-linear relationship with lumbar and thoracic BMD. Further studies are required to elucidate the mechanisms underlying this association.

The association between hemoglobin level and osteoporosis in a Chinese population with environmental lead and cadmium exposure

Low hemoglobin (Hb) level or anemia is associated with osteoporosis and bone fracture. Cadmium (Cd) and lead (Pb) exposure are also risk factors of osteoporosis and anemia. However, the role of anemia in Cd/Pb related bone loss remains unclear. The aim of present study was to investigate the association between Hb level and bone loss in a population with environmental lead and cadmium exposure. One hundred and ninety-four women and 108 men with different levels of Cd/Pb exposure were included in our study. The Cd/Pb exposure was determined using graphite-furnace atomic absorption spectrometry. Forearm bone mineral density (BMD) was determined by peripheral dual-energy X-ray absortiometry. Hb concentration was determined using an automatic blood cellcounter. A logistic model was established to predict the risk of osteoporosis. The BMDs of women that had the highest quartile BCd and BPb were markedly lower than that with the lowest quartile (p < 0.05). The BMD and the prevalence of osteoporosis in men with anemia were lower and higher than that with normal Hb (p < 0.05), respectively. In men, age, BPb and anemia were independent risk factors for osteoporosis. The odds ratio (OR) of men with anemia was 11.28 (95%confidence interval (CI):1.94-65.54) and 19.56 (95%CI: 2.98-128.78) compared to those with normal Hb after adjusting for potential cofounders. No such association was found in women. The area under the curve was 0.88 (95%CI: 0.82-0.96) in predicting osteoporosis using the logistic model in men. Linear discriminant analysis also showed that 90.7% of osteoporosis was correctly classified. Our data show that anemia is associated with incident of osteoporosis in men but not in women that environmentally exposed to Pb and Cd.

The Paradigm Shift from Polycythemia to Anemia in COPD: The Critical Role of the Renin-Angiotensin System Inhibitors

INTRODUCTION

Although polycythemia has been considered a common adverse event in COPD, anemia is reported more often and has gained more importance than polycythemia over the last thirty years.

AREAS COVERED

Factors considered to be associated with the development of anemia in COPD have included: Aging and kidney dysfunction with erythropoietin deficiency and bone marrow suppression due to uremic toxins; heart failure (HF), which is often encountered in COPD and is accompanied by anemia in one third of the cases; Low-grade chronic inflammation, which can directly suppresses the bone marrow and diminish iron absorption and utilization via increased hepcidin levels; long-term oxygen therapy (LTOT), which ameliorates chronic hypoxia, and most important, RAS inhibitors, which are widely used for the co-morbidities associated with COPD (hypertension, HF, CKD, diabetes) and have previously been shown to lower hematocrit values or cause anemia in various clinical conditions.

EXPERT OPINION

Introduction of LTOT in COPD and especially the established use of RAS inhibitors form the basis for the shift from polycythemia to anemia in COPD. Interestingly, when the SGLT2 inhibitors are introduced for cardiorenal protection in COPD, one could anticipate correction of anemia or even reemergence of polycythemia, since this new class of drugs can augment erythropoietin secretion and increase hematocrit values.

Association between Osteoporosis and Low Hemoglobin Levels: A Nested Case-Control Study Using a National Health Screening Cohort

An association between anemia and an increased risk of osteoporosis has been suggested. The goal of this study was to estimate the association of hemoglobin (Hb) level with osteoporosis. A total of 69,760 osteoporosis patients aged ≥ 40 years old from the Korean National Health Insurance Service Health Screening Cohort were enrolled. From an identical cohort database, 69,760 comparison participants were randomly selected. Hb levels before the onset of osteoporosis were evaluated. The association of Hb level with osteoporosis was analyzed using a conditional logistic regression model adjusted for obesity, smoking status, alcohol consumption, systolic blood pressure, diastolic blood pressure, fasting blood glucose, total cholesterol, and the Charlson comorbidity index score. Fifteen percent of the osteoporosis group and 14.17% of the comparison group had anemia. The Hb level was associated with 0.98-fold lower odds for osteoporosis (95% confidence intervals = 0.97-0.99, p < 0.001). A low Hb level was associated with a high risk of osteoporosis in the adult population. There was a consistent association between a low Hb level and osteoporosis in patients with comorbidities.

Implications of gender-based variabilities in bone mineral density and hemoglobin levels

BACKGROUND

Studies reported that there is a relationship between volumetric bone mineral density (vBMD) and hemoglobin (HGB) in sickle cell anemia, chronic obstructive pulmonary disease, inflammatory bowel disease, and chronic kidney disease, it is not clear whether this association exists in normal populations or different genders. In order to further clarify the relationship between vBMD and HGB, and provide the basis for the diagnosis of related diseases, this study was conducted in the physical examination population.

METHODS

A cross-sectional study was conducted on a health check-up population from Wannan area of China from January to December 2018. The study involved 1238 individuals aged 23 to 85 years. Linear regression analysis and smooth curve were applied to determine the relationship of HGB and vBMD.

RESULTS

The average level of vBMD in the population was 130.11 ± 79.51 mg/cm³, after adjusting for age, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), triglycerides (TG), glucose (GLU), high-density lipoprotein (HDL) and low-density lipoprotein (LDL). A U-shape relationship was established between vBMD and HGB, the cut off value of HGB was 130 g/L. After gender stratification, the results showed a U-shaped curve relationship between vBMD and HGB in male group, and a linear relationship between vBMD and HGB in female group. The vBMD decreased with HGB when HGB < 120 g/L, and increased when HGB ≥ 120 g/L in male group.

CONCLUSION

The relationship between vBMD and HGB in the male physical examination population presents a U-shaped curve.

Active hematopoiesis triggers exosomal release of PRDX2 that promotes osteoclast formation

Hematopoietic disorders, particularly hemolytic anemias, commonly lead to bone loss. We have previously reported that actively proliferating cancer cells stimulate osteoclastogenesis from late precursors in a RANKL-independent manner. We theorized that cancer cells exploit the physiological role of bone resorption to support expanding hematopoietic bone marrow and examined if hematopoietic cells can trigger osteoclastogenesis. Using phlebotomy-induced acute anemia in mice, we found strong correlation between augmented erythropoiesis and increased osteoclastogenesis. Conditioned medium (CM) from K562 erythroleukemia cells and primary mouse erythroblasts stimulated osteoclastogenesis when added to RANKL-primed precursors from mouse bone marrow or RAW264.7 cells. Using immunoblotting and mass spectrometry, PRDX2 was identified as a factor produced by erythroid cells in vitro and in vivo. PRDX2 was detected in K562-derived exosomes, and inhibiting exosomal release significantly decreased the osteoclastogenic capacity of K562 CM. Recombinant PRDX2 induced osteoclast formation from RANKL-primed primary or RAW 264.7 precursors to levels comparable to achieved with continuous RANKL treatment. Thus, increased bone marrow erythropoiesis secondary to anemia leads to upregulation of PRDX2, which is released in the exosomes and acts to induce osteoclast formation. Increased bone resorption by the osteoclasts expands bone marrow cavity, which likely plays a supporting role to increase blood cell production.

Helicobacter pylori Related Diseases and Osteoporotic Fractures (Narrative Review)

Osteoporosis (OP) and osteoporotic fractures (OFs) are common multifactorial and heterogenic disorders of increasing incidence. Helicobacter pylori (H.p.) colonizes the stomach approximately in half of the world's population, causes gastroduodenal diseases and is prevalent in numerous extra-digestive diseases known to be associated with OP/OF. The studies regarding relationship between H.p. infection (HPI) and OP/OFs are inconsistent. The current review summarizes the relevant literature on the potential role of HPI in OP, falls and OFs and highlights the reasons for controversies in the publications. In the first section, after a brief overview of HPI biological features, we analyze the studies evaluating the association of HPI and bone status. The second part includes data on the prevalence of OP/OFs in HPI-induced gastroduodenal diseases (peptic ulcer, chronic/atrophic gastritis and cancer) and the effects of acid-suppressive drugs. In the next section, we discuss the possible contribution of HPI-associated extra-digestive diseases and medications to OP/OF, focusing on conditions affecting both bone homeostasis and predisposing to falls. In the last section, we describe clinical implications of accumulated data on HPI as a co-factor of OP/OF and present a feasible five-step algorithm for OP/OF risk assessment and management in regard to HPI, emphasizing the importance of an integrative (but differentiated) holistic approach. Increased awareness about the consequences of HPI linked to OP/OF can aid early detection and management. Further research on the HPI-OP/OF relationship is needed to close current knowledge gaps and improve clinical management of both OP/OF and HPI-related disorders.

Low Hemoglobin Is Associated With Low Bone Mineral Density and High Risk of Bone Fracture in Male Adults: A Retrospective Medical Record Review Study

The aim of this study was to examine the association between serum hemoglobin level, bone mineral density, and fracture risks based on the estimated score of the Fracture Risk Assessment Tool (FRAX) in Asian male adults. The medical records of 662 male patients who underwent health examinations at a regional teaching hospital in southern Taiwan were reviewed. The medical history, demographic characteristics, clinical laboratory results, and bone mineral density of the patients were ascertained from their medical records. Simple and multiple linear regression analyses were conducted to evaluate the association of hemoglobin levels with bone mineral density, the 10-year risk of hip fracture, and the 10-year risk of major osteoporotic fracture (clinical spine, forearm, hip, or shoulder fracture) as assessed by FRAX. The mean age of the patients was 53.1 years. Results from simple linear regression analysis indicated that hemoglobin was positively associated with bone mineral density but inversely associated with both hip fracture risk and major osteoporotic fracture risk. Similar results were obtained when potential confounding variables were adjusted using multiple linear regression analysis. Low serum hemoglobin levels might be an important indicator for predicting bone mineral loss and the risk of both major osteoporotic fracture and hip fracture in male patients. Bone mineral density should be closely monitored in patients receiving treatment for anemia.

Hemoglobin levels and low bone mineral density in non-anemic older adults: Secondary analysis of the Korean National Health and Nutrition Examination Survey

BACKGROUND

Although, previous studies have reported a positive association between hemoglobin levels and bone mineral density (BMD), the majority of the studies were limited in patients with chronic hypoxemic conditions and findings concerning the association among non-anemic populations are inconclusive. We aimed to examine the association between hemoglobin levels and BMD in non-anemic healthy adults.

METHODS

This cross-sectional study included 3626 non-anemic men and women aged ≥ 60 years who participated in the Korean National Health and Nutrition Examination Survey (KNHANES). The BMD of the lumbar spine and both femurs was measured by dual-energy X-ray absorptiometry (DXA). Participants with T-score for BMD < -1.0 SD were defined as having low BMD. The odds ratios (ORs) and 95% confidence intervals (CIs) for low BMD were calculated using multiple logistic regression analyses across sex-specific hemoglobin quartiles.

RESULTS

The prevalence of low BMD gradually decreased in accordance with hemoglobin quartiles in both sexes. Compared with the group in the lowest quartile, the OR (95% CI) for low BMD in the lumbar spine was 0.78 (0.54-0.93) for men and 0.67 (0.50-0.93) for women after adjusting for age, BMI, tobacco smoking, alcohol intake, physical activity, walking difficulty, household income, total calorie intake, calcium intake, iron intake, 25(OH)D, alkaline phosphatase, and parathyroid hormone levels. However, these positive associations were not found in femur after adjusting for the same co-variables.

CONCLUSIONS

Hemoglobin levels were inversely associated with low BMD in lumbar spine among non-anemic adults.

Predictive and modifying factors of bone mineral density decline in patients with COPD

RATIONALE

Various determinants of osteoporosis have been previously identified. However, only a few longitudinal studies have examined related factors. We aimed to investigate factors predicting and modifying rapid decline of bone mineral density in patients with chronic obstructive pulmonary disease.

METHODS

We analyzed patients with chronic obstructive pulmonary disease whose bone mineral density were measured at least three times over three years (n = 111). We divided annual per cent changes of bone mineral density in different body parts into tertiles. Rapid decliners (n = 33) were defined as those with the largest decline in at least two parts; all other participants were defined as non-rapid decliners (n = 78).

RESULTS

At enrollment, bone mineral density did not differ between the two groups. However, rapid decliners had a significantly greater rate of new vertebral fractures over 3 years compared with non-rapid decliners. On multivariate logistic regression analysis, age, moderate to severe emphysema, no daily exercise habits, and anemia increased the likelihood of rapid decliners. Furthermore, patients who newly started and continued bisphosphonate exhibited higher annual per cent changes of bone mineral density than did those without bisphosphonate use.

CONCLUSIONS

A rapid decline in bone mineral density correlates to a higher likelihood of vertebral fracture. We clarified the predictors of bone mineral density decline and demonstrated that bisphosphonate use might modify bone mineral density in patients with chronic obstructive pulmonary disease.

The Effect of Exercise on Oxygen Content in Anemic Patients With Chronic Obstructive Pulmonary Disease

Background:

Anemia is reported in one-third of the patients with chronic obstructive pulmonary disease (COPD). Anemia, by decreasing oxygen content, can be a contributing factor for hypoxemia. We determined to find whether anemia causes more prominent hypoxia by decreasing the total oxygen content after exercise in anemic patients with COPD.

Methods:

Stable moderate-to-severe COPD patients with and without anemia were recruited. Arterial blood gas analyses were performed on room air before and after a 6-minute walking test (6MWT). Walking distance, oxygen saturation, and heart rate were recorded in each case before and after the 6MWT. Pulmonary function test measurements and other data were obtained from the chart. The mean and standard deviations were calculated for continuous variables. The independent t-test and Kruskal-Wallis test were performed for numerical covariate and univariate analyses. The paired t-test was used for the analyses of data before and after exercise.

Results:

A total of 24 male patients were included in the study; 12 of which were anemic. The oxygen content was decreased in the anemic group (15.22 ± 1.28 vs 15.07 ± 1.22) after exercise, but it was not significant. In the non-anemic group, no oxygen content decrease was observed after exercise (18.83 ± 1.41 vs 18.9 ± 1.37). Interestingly, the Spo₂, but not Sao₂, was significantly lower after exercise in anemic patients with COPD (93.46% ± 5.06% vs 88.20% ± 6.35% before and after exercise, respectively).

Conclusions:

Anemia does not cause more prominent hypoxemia after exercise in patients with COPD. However, the recorded Spo₂ levels were significantly lower after exercise in the anemic patients with COPD.

[The forensic medical estimation of the biological age of the corpse based on the morphological changes in the skin]

The objective of the present work was the immunohistochemical evaluation of the age-related dynamics of apoptosis-associated proteins contained in the human skin epidermis. We studied the samples of skin tissues obtained during the forensic medical expertises of 100 corpses of the subjects who died in the consequence of acute blood loss in the absence of injuries or pathological changes in the skin (56 men and 44 women at the age varying from 5 to 85 years). The results of this study give evidence that the histoimmunological investigations of the skin tissues can be carried out with the use of the mmunohistochemical Ki67, bcl-2, and p53 markers for the more accurate determination of the biological age of the deceased subjects. The quantitative characteristics thus obtained serve as reliable indicators of the chronic changes in the skin and can be used as the components of the combined diagnostic procedures.

Association between Hemoglobin Level and Bone Mineral Density in Korean Adults

Background

Low bone mineral density (BMD) increases fracture risk. Anemia is highly prevalent. Some studies suggested that anemia is an independent risk factor for osteoporosis. The aim of this study was to evaluate the association between hemoglobin (Hb) level and BMD in Korean adults.

Methods

This study was based on data from the Korea National Health and Nutrition Examination Survey 2008 to 2011. Propensity score-matching was performed to establish a dataset for analysis. Regression analyses were used to evaluate the association between Hb and BMD. Mean BMD scores were compared between normal and anemia groups, and among normal, anemia with low ferritin, and anemia without low ferritin groups.

Results

There were partial positive associations between Hb and BMD in men, but negative associations in women. The normal group had lower mean BMD scores than the anemia group in men. However, the anemia group had higher whole-body and lumbar-spine BMD scores than the normal group in women. In a comparison of the three groups, the anemia without low ferritin group had the lowest all-site BMD scores in men and women. However, the anemia with low ferritin group had the highest all-site BMD scores in women. In postmenopausal women, the anemia without low ferritin group had the lowest all-site BMD scores. In premenopausal women, the anemia with low ferritin group had the highest whole-body BMD scores.

Conclusions

This study found that Hb and anemia status were associated with BMD scores. However, the associations were different according to sex. This may be due to the etiology of anemia or low Hb levels.

The impact of anaemia and iron deficiency in chronic obstructive pulmonary disease: A clinical overview

INTRODUCTION

Anaemia is increasingly recognised as an important comorbidity in the context of chronic obstructive pulmonary disease (COPD), but remains undervalued in clinical practice. This review aims to characterise the impact of anaemia and iron deficiency in COPD.

METHODS

Literature review of studies exploring the relationship between anaemia/iron deficiency and COPD, based on targeted MEDLINE and Google Scholar queries.

RESULTS

The reported prevalence of anaemia in COPD patients, ranging from 4.9% to 38.0%, has been highly variable, due to different characteristics of study populations and lack of a consensus on the definition of anaemia. Inflammatory processes seem to play an important role in the development of anaemia, but other causes (including nutritional deficiencies) should not be excluded from consideration. Anaemia in COPD has been associated with increased morbidity, mortality, and overall reduced quality of life. The impact of iron deficiency, irrespective of anaemia, is not as well studied, but it might have important implications, since it impacts production of red blood cells and respiratory enzymes. Treatment of anaemia/iron deficiency in COPD remains poorly studied, but it appears reasonable to assume that COPD patients should at least receive the same type of treatment as other patients.

CONCLUSIONS

Anaemia and iron deficiency continue to be undervalued in most COPD clinical settings, despite affecting up to one-third of patients and having negative impact on prognosis. Special efforts should be made to improve clinical management of anaemia and iron deficiency in COPD patients as a means of achieving better patient care.

Impact of anaemia on lung function and exercise capacity in patients with stable severe chronic obstructive pulmonary disease

OBJECTIVE

This study intended to search for potential correlations between anaemia in patients with severe chronic obstructive pulmonary disease (COPD; GOLD stage III) and pulmonary function at rest, exercise capacity as well as ventilatory efficiency, using pulmonary function test (PFT) and cardiopulmonary exercise testing (CPET).

SETTING

The study was undertaken at Shanghai Pulmonary Hospital, a tertiary-level centre affiliated to Tongji University. It caters to a large population base within Shanghai and referrals from centres in other cities as well.

PARTICIPANTS

157 Chinese patients with stable severe COPD were divided into 2 groups: the anaemia group (haemoglobin (Hb) <12.0 g/dL for males, and <11 g/dL for females (n=48)) and the non-anaemia group (n=109).

PRIMARY AND SECONDARY OUTCOME MEASURES

Arterial blood gas, PFT and CPET were tested in all patients.

RESULTS

(1) Diffusing capacity for carbon monoxide (DLCO) corrected by Hb was significantly lower in the anaemia group ((15.3±1.9) mL/min/mm Hg) than in the non-anaemia group ((17.1±2.1) mL/min/mm Hg) (p<0.05). A significant difference did not exist in the level of forced expiratory volume in 1 s (FEV1), FEV1%pred, FEV1/forced vital capacity (FVC), inspiratory capacity (IC), residual volume (RV), total lung capacity (TLC) and RV/TLC (p>0.05). (2) Peak Load, Peak oxygen uptake (VO2), Peak VO2%pred, Peak VO2/kg, Peak O2 pulse and the ratio of VO2 increase to WR increase (ΔVO2/ΔWR) were significantly lower in the anaemia group (p<0.05); however, Peak minute ventilation (VE), Lowest VE/carbon dioxide output (VCO2) and Peak dead space/tidal volume ratio (VD/VT) were similar between the 2 groups (p>0.05). (3) A strong positive correlation was found between Hb concentration and Peak VO2 in patients with anaemia (r=0.702, p<0.01).

CONCLUSIONS

Anaemia has a negative impact on gas exchange and exercise tolerance during exercise in patients with severe COPD. The decrease in amplitude of Hb levels is related to the quantity of oxygen uptake.

Osteoporosis in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a lifestyle-related chronic inflammatory pulmonary disease associated with significant morbidity and mortality worldwide. COPD is associated with various comorbidities found in all stages of COPD. The comorbidities have significant impact in terms of morbidity, mortality, and economic burden in COPD. Management of comorbidities should be incorporated into the comprehensive management of COPD as this will also have an effect on the outcome in COPD patients. Various comorbidities reported in COPD include cardiovascular disease, skeletal muscle dysfunction, anemia, metabolic syndrome, and osteoporosis. Osteoporosis is a significant comorbidity in COPD patients. Various risk factors, such as tobacco smoking, systemic inflammation, vitamin D deficiency, and the use of oral or inhaled corticosteroids (ICSs) are responsible for its occurrence in patients with COPD. This review will focus on the prevalence, pathogenesis, risk factors, diagnosis, and treatment of osteoporosis in COPD patients.

Anaemia in chronic obstructive pulmonary disease: an insight into its prevalence and pathophysiology

Chronic obstructive pulmonary disease (COPD) is a major health problem, with increasing morbidity and mortality. There is a growing literature regarding the extra-pulmonary manifestations of COPD, which can have a significant impact on symptom burden and disease progression. Anaemia is one of the more recently identified co-morbidities, with a prevalence that varies between 4.9% and 38% depending on patient characteristics and the diagnostic criteria used. Systemic inflammation seems to be an important factor for its establishment and repeated bursts of inflammatory mediators during COPD exacerbations could further inhibit erythropoiesis. However, renal impairment, malnutrition, low testosterone levels, growth hormone level abnormalities, oxygen supplementation, theophylline treatment, inhibition of angiotensin-converting enzyme and aging itself are additional factors that could be associated with the development of anaemia. The present review evaluates the published literature on the prevalence and significance of anaemia in COPD. Moreover, it attempts to elucidate the reasons for the high variability reported and investigates the complex pathophysiology underlying the development of anaemia in these patients.

The systemic nature of chronic lung disease

The systemic effects and comorbidities of chronic respiratory disease such as COPD contribute substantially to its burden. Symptoms in COPD do not solely arise from the degree of airflow obstruction as exercise limitation is compounded by the specific secondary manifestations of the disease including skeletal muscle impairment, osteoporosis, mood disturbance, anemia, and hormonal imbalance. Pulmonary rehabilitation targets the systemic manifestations of COPD, the causes of which include inactivity, systemic inflammation, hypoxia and corticosteroid treatment. Comorbidities are common, including cardiac disease, obesity, and metabolic syndrome and should not preclude pulmonary rehabilitation as they may also benefit from similar approaches.

Osteoporosis in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is being regarded as a heterogeneous disease with clinically significant pulmonary and extrapulmonary manifestations, such as emphysema, cardiovascular disease and osteoporosis. Osteoporosis is characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility and, consequently, an increased risk of fracture. Fractures resulting from osteoporosis might contribute to increased morbidity and mortality, particularly in COPD patients. The high prevalence of osteoporosis in COPD patients is assumed to be due to common risk factors, such as older age and tobacco smoking, and COPD-specific risk factors, such as systemic inflammation, vitamin D deficiency and the use of oral or inhaled corticosteroids. This review provides a state-of-the-art summary of the prevalence, pathophysiology, diagnosis, risk factors and treatment of osteoporosis in COPD patients. It also discusses potential mechanisms linking COPD with osteoporosis.