Prevalence of metabolic syndrome in COPD patients and its consequences

Glycemic Profile and Lipid Profile in Chronic Obstructive Pulmonary Disease (COPD) Patients With and Without Metabolic Syndrome

OBJECTIVES

There is a lack of Indian data regarding the frequency of metabolic syndrome (MetS) or its components in chronic obstructive pulmonary disease (COPD). As a result, the present study aimed to determine the prevalence of MetS in COPD cases and investigate its association with COPD severity.

MATERIAL

After receiving ethical approval from Index Medical College and Hospital, we conducted this cross-sectional study in Indore. We recruited 100 participants with a history of COPD and divided them into two groups: those with MetS and those without. Researchers examined the subjects' fasting blood glucose, serum high-density lipoprotein, triglyceride (TG), systolic and diastolic blood pressure (SBP/DBP), waist circumference, and fasting blood glucose levels.

RESULTS

We discovered that 59% of patients with COPD and 52% of individuals with impaired fasting glucose (IFG) had MetS (mean ± SD = 110.8 ± 32.8). In comparison, 48% (mean ± SD = 98.2 ± 24.8) of individuals with normal fasting glucose do not experience this. The incidence of MetS was higher in both groups, those with IFG and those without, but the difference was not statistically significant (t = 1.7088, df = 98; p = 0.0907). We observed X2 = 1.336, df = 1, and p = 0.2476 when we tested the association between IFG and COPD with the Chi-square test.

CONCLUSION

Individuals with MetS were more likely to have high BP, raised TG levels, low HDL cholesterol, abdominal obesity, and other risk factors.

Independent effect of the triglyceride-glucose index on all-cause mortality in critically ill patients with chronic obstructive pulmonary disease and asthma: A retrospective cohort study

BACKGROUND

The triglyceride-glucose (TyG) index serves as a reliable proxy for insulin resistance (IR). IR has been linked to heightened incidence, prevalence, or severity of chronic obstructive pulmonary disease (COPD) and asthma. Prior research indicates that critically ill patients are prone to developing IR. Nevertheless, few studies have delved into the correlation between IR and all-cause mortality in critically ill patients with COPD and asthma. Therefore, the aim of this study is to explore the association between the TyG index and all-cause mortality in patients with COPD and asthma, with the goal of assessing the impact of IR on the prognosis of this patient population.

METHODS

This is a retrospective study, and all data are from the Medical Information Mart for Intensive Care IV (MIMIC-IV) critical care database. This study included 684 ICU patients with COPD and asthma and divided them into quartiles based on TyG index levels. The primary outcomes of this study were all-cause mortality during follow-up, encompassing mortality at 30 days, 90 days, and 180 days. The Kaplan-Meier analysis was used to compare all-cause mortality among the above four groups. Cox proportional hazards analyses were performed to examine the association between TyG index and all-cause mortality in critically ill patients with COPD and asthma. Restricted cubic spline analysis was used to assess potential nonlinear association between the TyG index and the primary outcome.

RESULTS

A total of 684 patients (53.9% female) were included. The 90-days all-cause mortality rate and 180-days all-cause mortality were 11.7% and 12.3%, respectively. Kaplan-Meier analysis revealed a significant association between the TyG index and both 90-days all-cause mortality (log-rank p = .039) and 180-days all-cause mortality (log-rank p = .017). Cox proportional hazards analysis revealed a significant association between the TyG index and 90-days all-cause mortality in both the unadjusted model (HR, 1.30 [95% CI 1.08-1.57] p = .005) and the model adjusted for age, gender, and diabetes (HR, 1.38 [95% CI 1.15-1.67] p < .001). Similarly, the TyG index was associated with 180-days all-cause mortality in the unadjusted model (HR, 1.30 [95% CI 1.09-1.56] p = .004) and the model adjusted for age, sex, and diabetes (HR, 1.38 [95% CI 1.15-1.66] p < .001). The restricted cubic splines (RCS) regression model indicated a significant nonlinear association between the TyG index and both 90-days and 180-days all-cause mortality. Specifically, TyG index >4.8 was associated with an increased risk of mortality at both 90 days and 180 days.

CONCLUSIONS

In summary, our results extend the utility of the TyG index to critically ill patients with COPD and asthma. Our study shows that the TyG index is a potential predictor of all-cause mortality in critically ill patients with COPD and asthma. In addition, in patients with a TyG index exceeding 4.8, there was a heightened risk of mortality. Measuring the TyG index may help with risk stratification and prognosis prediction in critically ill patients with COPD and asthma. Further prospective studies are needed to confirm our findings.

Mechanisms Linking COPD to Type 1 and 2 Diabetes Mellitus: Is There a Relationship between Diabetes and COPD?

Chronic obstructive pulmonary disease (COPD) patients frequently suffer from multiple comorbidities, resulting in poor outcomes for these patients. Diabetes is observed at a higher frequency in COPD patients than in the general population. Both type 1 and 2 diabetes mellitus are associated with pulmonary complications, and similar therapeutic strategies are proposed to treat these conditions. Epidemiological studies and disease models have increased our knowledge of these clinical associations. Several recent genome-wide association studies have identified positive genetic correlations between lung function and obesity, possibly due to alterations in genes linked to cell proliferation; embryo, skeletal, and tissue development; and regulation of gene expression. These studies suggest that genetic predisposition, in addition to weight gain, can influence lung function. Cigarette smoke exposure can also influence the differential methylation of CpG sites in genes linked to diabetes and COPD, and smoke-related single nucleotide polymorphisms are associated with resting heart rate and coronary artery disease. Despite the vast literature on clinical disease association, little direct mechanistic evidence is currently available demonstrating that either disease influences the progression of the other, but common pharmacological approaches could slow the progression of these diseases. Here, we review the clinical and scientific literature to discuss whether mechanisms beyond preexisting conditions, lifestyle, and weight gain contribute to the development of COPD associated with diabetes. Specifically, we outline environmental and genetic confounders linked with these diseases.

Metabolic syndrome in patients with COPD: Causes and pathophysiological consequences

BACKGROUND

Decreased physical activity significantly increases the probability of prevalent metabolic syndrome (MetS) with substantial impact on the expected course of COPD.

OBJECTIVE

Our research aims to assess the metabolic consequences of chronic obstructive pulmonary disease (COPD) and evaluate the prevalence of MetS and its interrelations with age, sex, comorbidities, drug intake, degree of decreased lung function, nutritional status, physical activity and quality of life.

METHODS

A cross-sectional study was performed on a random sample (n = 401) at the Department of Pulmonary Rehabilitation of the National Koranyi Institute of Pulmonology from March 1, 2019 to March 1, 2020 in Budapest, Hungary. Anthropometric and respiratory function tests and laboratory parameters of all patients were registered.

RESULTS

MetS occurred in 59.1% of COPD patients with significant gender difference (male: 49.7% female: 67.6%). Concerning BMI, the prevalence of MetS was higher with BMI≥25 kg m-2 (P < 0.0001). Patients with this syndrome had significantly worse FEV1%pred (43 (30-56) vs. 47 (36-61); P = 0.028), lower quality of life (CAT: 26 (21-32) vs. 24.5 (19-29); P = 0.049) and significantly more frequent exacerbations (2 (1-3) vs.1 (0-2); P < 0.05), than patients without MetS. The prevalence of comorbidities were higher in overweight/obese patients (BMI> 25 kg m-2).

CONCLUSIONS

In COPD patients MetS negatively affect respiratory function and quality of life and promotes exacerbations of the disease. MetS is related to nutritional status and the level of systemic inflammation in COPD patients.

The Prevalence of Metabolic Syndrome, Scoring, and Comparison in People With and Without COPD: Evidence from Shahrekord PERSIAN Cohort Study

Background: Comorbidities are common in patients with chronic obstructive pulmonary diseases (COPDs), including metabolic syndrome (MetS). This study aimed to determine the prevalence of MetS and its components in people with and without COPD. Methods: This population-based study was performed on 6961 adults in the Shahrekord Prospective Epidemiological Research Studies in Iran. Data collection, spirometry, and COPD diagnosis were performed according to the cohort protocol from 2015 to 2019. The data were analyzed by two independent sample t-tests, analysis of covariance, chi-square, and odds ratio (OR) with 95% confidence interval (95% CI) in logistic regression models. P value <0.05 was considered statistically significant. All analyses were conducted using Stata Statistical Software Release 16 (Stata Corp., College Station, TX). Results: The prevalence of MetS in patients with and without COPD was 28.4% and 31%, respectively. The most common components of MetS in people with COPD were low high-density lipoprotein cholesterol (47.4%), waist circumference (43.9%), and high fasting plasma glucose (39.3%). There was a statistically significant difference in the frequency of respiratory dysfunction between people with and without MetS. Being older than 60 (OR = 2.20, 95% CI: 1.72-2.80), female (OR = 1.36, 95% CI: 1.49-1.97), obese (OR = 11.17, 95% CI: 9.02-13.62), and uneducated (OR = 1.80, 95% CI: 1.49-2.17), and living in urban areas (OR = 1.96, 95% CI: 1.64-2.35) are stronger predictors of MetS in this population. Conclusion: There was no significant difference in the prevalence of MetS between patients with and without COPD. Spirometry parameters and respiratory problems were significant in subjects with and without MetS.

Role of interluekin-6 and insulin resistance as screening markers for metabolic syndrome in patients of chronic obstructive pulmonary disease. A hospital based cross-sectional study

Chronic obstructive pulmonary disease (COPD) is usually associated with a variety of extra-pulmonary manifestations. Metabolic syndrome (MetS) is one such entity that has been scarcely studied in Indian patients. Availability of a good screening marker may help in timely detection of this co morbidity in COPD patients. We conducted a cross sectional study to evaluate the prevalence of MetS among COPD patients and to evaluate the role of Interleukin-6 and insulin resistance (as measured by HOMA-IR) as screening markers for MetS in COPD. A total of 100 stable COPD patients were evaluated for MetS using US National Cholesterol Education Program Adult Treatment Panel III (2005) guidelines. Interleukin-6 and HOMA-IR (for insulin resistance) were measured and compared between COPD patients with and without MetS. ROC analysis was done to find the best cut-off value and sensitivity and specificity of both the molecules in detecting MetS. In the results, the mean age of the study cohort was 59.9+8.7yrs (males=93). Forty five COPD patients (45%) fulfilled the criteria for MetS. Patients with MetS were comparatively younger (57.9+9.5 v/s 61.6+7.8 years; p=0.037) but had longer duration of preceding COPD (9.9+2.8 v/s 6.0+2.2 years; p<0.001) as compared to those without MetS. Both IL-6 and HOMA index were statistically higher (p<0.05) in COPD-MetS patients as compared to the other group. At cutoff value of 36.3 pg/ml for IL-6 and 1.61 for HOMA index, IL-6 and HOMA-IR had sensitivity 91.1% and 82.2% respectively in detecting MetS among COPD patients. To conclude, metabolic syndrome is a common comorbidity seen in COPD patients. Interleukin-6 has a better sensitivity than HOMA-IR in screening MetS among COPD patients.

Association of Triglyceride-Glucose Index and Lung Health: A Population-based Study

BACKGROUND

Metabolic syndrome and insulin resistance are associated with worsened outcomes of chronic lung disease. The triglyceride-glucose index (TyG), a measure of metabolic dysfunction, is associated with metabolic syndrome and insulin resistance, but its relationship to lung health is unknown.

RESEARCH QUESTION

What is the relationship of TyG to respiratory symptoms, chronic lung disease, and lung function?

STUDY DESIGN AND METHODS

This study analyzed data from the National Health and Nutrition Examination Survey from 1999 to 2012. Participants included fasting adults age ≥ 40 years (N = 6,893) with lung function measurements in a subset (n = 3,383). Associations of TyG with respiratory symptoms (cough, phlegm production, wheeze, and exertional dyspnea), chronic lung disease (diagnosed asthma, chronic bronchitis, and emphysema), and lung function (FEV₁, FVC, and obstructive or restrictive spirometry pattern) were evaluated, adjusting for sociodemographic variables, comorbidities, and smoking. TyG was compared vs insulin resistance, represented by the homeostatic model assessment of insulin resistance (HOMA-IR), and vs the metabolic syndrome.

RESULTS

TyG was moderately correlated with HOMA-IR (Spearman ρ = 0.51) and had good discrimination for metabolic syndrome (area under the receiver-operating characteristic curve, 0.80). A one-unit increase in TyG was associated with higher odds of cough (adjusted OR [aOR], 1.28; 95% CI, 1.06-1.54), phlegm production (aOR, 1.20; 95% CI, 1.01-1.43), wheeze (aOR, 1.18; 95% CI, 1.03-1.35), exertional dyspnea (aOR, 1.21; 95% CI, 1.07-1.38), and a diagnosis of chronic bronchitis (aOR, 1.21; 95% CI, 1.02-1.43). TyG was associated with higher relative risk of a restrictive spirometry pattern (adjusted relative risk ratio, 1.45; 95% CI, 1.11-1.90). Many associations were maintained with additional adjustment for HOMA-IR or metabolic syndrome.

INTERPRETATION

TyG was associated with respiratory symptoms, chronic bronchitis, and a restrictive spirometry pattern. Associations were not fully explained by insulin resistance or metabolic syndrome. TyG is a satisfactory measure of metabolic dysfunction with relevance to pulmonary outcomes. Prospective study to define TyG as a biomarker for impaired lung health is warranted.

Intercellular Communication by Vascular Endothelial Cell-Derived Extracellular Vesicles and Their MicroRNAs in Respiratory Diseases

Respiratory diseases and their comorbidities, such as cardiovascular disease and muscle atrophy, have been increasing in the world. Extracellular vesicles (EVs), which include exosomes and microvesicles, are released from almost all cell types and play crucial roles in intercellular communication, both in the regulation of homeostasis and the pathogenesis of various diseases. Exosomes are of endosomal origin and range in size from 50 to 150 nm in diameter, while microvesicles are generated by the direct outward budding of the plasma membrane in size ranges of 100-2,000 nm in diameter. EVs can contain various proteins, metabolites, and nucleic acids, such as mRNA, non-coding RNA species, and DNA fragments. In addition, these nucleic acids in EVs can be functional in recipient cells through EV cargo. The endothelium is a distributed organ of considerable biological importance, and disrupted endothelial function is involved in the pathogenesis of respiratory diseases such as chronic obstructive pulmonary disease, pulmonary hypertension, and acute respiratory distress syndrome. Endothelial cell-derived EVs (EC-EVs) play crucial roles in both physiological and pathological conditions by traveling to distant sites through systemic circulation. This review summarizes the pathological roles of vascular microRNAs contained in EC-EVs in respiratory diseases, mainly focusing on chronic obstructive pulmonary disease, pulmonary hypertension, and acute respiratory distress syndrome. Furthermore, this review discusses the potential clinical usefulness of EC-EVs as therapeutic agents in respiratory diseases.

Association between insulin resistance and BMI with FEV1 in non-hypoxemic COPD out-patients

OBJECTIVES

This study was conducted to determine the impact of insulin resistance using Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) score and BMI in non-hypoxemic out-patients with COPD on FEV₁ using linear and polynomial regressions and to determine their correlation.

METHODS

COPD patients of both genders were included after informed consent. Fasting blood sugar and serum insulin were done to calculate HOMA-IR, which were segregated into two groups of ≥ 3 and < 3 labeled insulin resistance present and absent, these were compared with BMI. Patients were segregated into GOLD Grade 1-4 per GOLD Guidelines and compared with HOMA-IR and BMI. Curve and linear regressions, multivariate and univariate analysis of HOMA-IR with BMI, FVC, and FEV₁ were done.

RESULTS

A total of 273 subjects were inducted after informed consent. There was a linear correlation between HOMA-IR and BMI (r² 0.498, P < 0.001) and nonlinear correlation between HOMA-IR and FEV1 (r² 0. 617, P < 0.001) which showed little evidence of association above FEV1 > 60 predicted, but a clear negative association below that. Significant increase in HOMA-IR was seen from GOLD-2 to 3 and from GOLD-3 to 4 classes. The impact of HOMA-IR on FEV1 was 49.9% (P < 0.001) on FVC was 43.7%.

CONCLUSIONS

The results indicate that there is a high prevalence of IR in non-hypoxemic COPD. A nonlinear association is present between FEV1 and HOMA-IR which is most evident with FEV1 <60% predicted.

Prevalence of different comorbidities in chronic obstructive pulmonary disease among Shahrekord PERSIAN cohort study in southwest Iran

Comorbidities are common in chronic obstructive pulmonary disease (COPD) patients. This study was conducted to determine the prevalence of common comorbidities in patients with COPD compared with people without COPD. This cross-sectional, population-based study was performed on 6961 adults aged 35-70 years enrolled in the Shahrekord PERSIAN cohort study. Data (demographic and clinical characteristics, comorbidities, anthropometric and blood pressure measurements, laboratory, and spirometry tests) collection was performed according to the cohort protocol from 2015 to 2019. In the present study, 215 (3.1%) patients were diagnosed with COPD and 1753 (25.18%) ones with restrictive lung patterns. The mean age of COPD patients was 52.5 ± 9.76 years. 55.8% of patients were male, 17.7% were current smokers and 12.1% had a history of smoking or were former smokers. 5.6% of patients had no comorbidity and 94.5% had at least one comorbidity. The most common comorbidities in COPD patients were dyslipidemia (70.2%), hypertension (30.2%), metabolic syndrome (22.8%), and diabetes (16.7%). The most common comorbidities in individuals with a restrictive spirometry pattern were dyslipidemia (68.9%), metabolic syndrome (27.2%), hypertension (26.1%), depression (17.6%), and fatty liver (15.5%). The logistic regression analysis with 95% confidence interval (95%CI) of odds ratio (OR) showed that comorbidities of chronic lung diseases (OR = 2.12, 95% CI 1.30-3.44), diabetes (OR = 1.54, 95%CI 1.03-2.29), cardiovascular disease (OR = 1.52, 95%CI 1.17-2.43), and hypertension (OR = 1.4, 95%CI 1.02-1.99) were more likely to occur in COPD patients than in healthy individuals. Knowing these prevalence rates and related information provides new insights on comorbidities to reduce disease burden and develop preventive interventions and to regulate health care resources to meet the needs of patients in primary health care.

Effects of peripheral and different inspiratory muscle training methods in coronary artery disease patients with metabolic syndrome: A randomized-controlled trial

Background OBJECTIVE: To investigate the effects of peripheral muscle training (PMT) and different inspiratory muscle training (IMT) methods on respiratory functions, exercise capacity, and biochemistry parameters in coronary artery disease patients with metabolic syndrome.

METHODS

This prospective, single-blind, randomized-controlled study included 60 patients of stable coronary artery disease with metabolic syndrome (New York Heart Association [NYHA] Class I-II, left ventricular ejection fraction >40%). Patients were randomly divided into three groups: neuromuscular electrical stimulation (NMES) plus PMT group (NMES + PMT group, n = 20), IMT plus PMT group (IMT + PMT group, n = 20) and PMT group (PMT group, n = 20). Treatment continued for six weeks for all groups. The NMES was applied to rectus abdominis, IMT was applied with 30% of maximal inspiratory pressures, and PMT was applied at home. Spirometry, maximal inspiratory and expiratory pressure, dyspnea scores, exercise stress test, and biochemistry parameters were measured before and after training.

RESULTS

There were significant improvements in spirometric tests, respiratory muscle strength, dyspnea scores, exercise capacity, fasting blood glucose, and antistreptolysin O after treatment in all groups (p < 0.05). Significant improvements in C-reactive protein and erythrocyte sedimentation rate were observed in NMES + PMT and IMT + PMT groups (p < 0.05). Among the groups, there was a significant difference in maximal inspiratory pressure (p = 0.02) and erythrocyte sedimentation rate (p = 0.037) in favor of NMES + PMT group (p < 0.05).

CONCLUSION

Our study results showed significant improvements in respiratory functions, exercise capacity, and biochemistry markers in all groups. Different IMT methods can be used in cardiopulmonary rehabilitation to improve exercise intolerance in coronary artery disease patients with metabolic syndrome.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03523026.

Prevalence of metabolic syndrome in patients with chronic obstructive pulmonary disease: An observational study in South Indians

BACKGROUND AND AIMS

Metabolic syndrome (MetS) has a significant association with airflow obstruction and physical inactivity, which are the relevant extra-pulmonary markers of chronic obstructive respiratory disease (COPD). This study aimed to estimate the prevalence of MetS and its correlation with comorbidities and health related quality of life (HRQoL) in South Indian patients with COPD.

METHODS

A cross-sectional study was conducted among the 76 COPD patients. Pulmonary function test (PFT) and parameters for MetS such as waist circumference, blood pressure, fasting blood glucose, triglycerides (TGs) and high density lipoprotein cholesterol (HDL-C) levels of COPD patients were measured. HRQoL was calculated using Saint George Respiratory Questionnaire (SGRQ).

RESULTS

54% of COPD patients were presented with MetS especially in stage II and III. TGs and HDL-C were significantly associated with the severity of COPD (p < 0.05), while waist circumference, TGs and HDL-C were significantly (p < 0.05) correlated with PFT. Symptom, activity, impact and total scores of SGRQ was increased statistically (p < 0.05) in COPD patients with MetS than without MetS.

CONCLUSION

According to our findings, screening the grade II and III COPD patients for the presence of MetS is a reasonable option. The results of this study should be confirmed with a larger sample of population.

Metabolic profiles among COPD and controls in the CanCOLD population-based cohort

A high prevalence of intermediate cardiometabolic risk factors and obesity in chronic obstructive pulmonary disease (COPD) has suggested the existence of pathophysiological links between hypertriglyceridemia, insulin resistance, visceral adiposity, and hypoxia or impaired pulmonary function. However, whether COPD contributes independently to the development of these cardiometabolic risk factors remains unclear. Our objective was to compare ectopic fat and metabolic profiles among representative individuals with COPD and control subjects and to evaluate whether the presence of COPD alters the metabolic risk profile. Study participants were randomly selected from the general population and prospectively classified as non-COPD controls and COPD, according to the Global Initiative for Chronic Obstructive Lung Disease classification. The metabolic phenotype, which consisted of visceral adipose tissue area, metabolic markers including homeostasis model assessment of insulin resistance (HOMA-IR), and blood lipid profile, was obtained in 144 subjects with COPD and 119 non-COPD controls. The metabolic phenotype was similar in COPD and controls. The odds ratios for having pathologic values for HOMA-IR, lipids and visceral adipose tissue area were similar in individuals with COPD and control subjects in multivariate analyses that took into account age, sex, body mass index, tobacco status and current medications. In a population-based cohort, no difference was found in the metabolic phenotype, including visceral adipose tissue accumulation, between COPD and controls. Discrepancies between the present and previous studies as to whether or not COPD is a risk factor for metabolic abnormalities could be related to differences in COPD phenotype or disease severity of the study populations.

The Effect of Metabolic Syndrome Status on Lung Function and Patient-reported Outcomes in Patients with COPD Receiving Nebulized Glycopyrrolate

Background

Concurrent chronic obstructive pulmonary disease (COPD) and metabolic syndrome (MetS) represent an important clinical phenotype with overlapping symptomology. The effect of MetS in COPD patients was assessed following treatment with nebulized glycopyrrolate (GLY; administered via eFlow® Closed System Nebulizer).

Methods

Posthoc analyses were performed on pooled lung function, patient-reported outcome (PRO) and safety data by MetS status from patients treated with placebo, GLY 25 and 50 mcg twice daily in two 12-week studies (GOLDEN 3 and 4; N=1293). Patients with MetS were characterized as having ≥ 3 of hypertension, hyperlipidemia, diabetes, body mass index (BMI) > 30 kg/m² risk factors. The results are presented for the Food and Drug Administration-approved GLY 25 mcg dose.

Results

A total of25% of patients met MetS criteria.At baseline, the MetS subgroup had higher BMIs, more ex-smokers, greater incidences of cardiovascular risk factors, and MetS-specific risk factors were 2-14 times higher than non-MetS. At 12 weeks, GLY produced significant, clinically important improvements (MetS: 0.121 L; non-MetS: 0.083 L) in trough forced expiratory volume in 1 second. In the non-MetS group, significant improvements occurred in the St George's Respiratory Questionnaire (MetS: -2.28, p=0.157; non-MetS: -3.71) and Evaluating Respiratory Symptoms in COPD tool (MetS: 0.42, p=0.574; non-MetS: -1.61) total scores. Incidence of adverse events was similar with GLY versus placebo regardless of MetS status.

Conclusion

GLY was well-tolerated and significantly improved lung function regardless of MetS status, while significant PRO improvements occurred in non-MetS patients. These results highlight the importance of comorbidities on bronchodilator responses and patient symptoms in COPD patients.

Organizational aspects of pulmonary rehabilitation in chronic respiratory diseases

Adult patients with chronic respiratory diseases may suffer from multiple physical (pulmonary and extra-pulmonary), emotional and social features which necessitate a comprehensive, interdisciplinary rehabilitation programme. To date, pulmonary rehabilitation programmes show a lot of variation in setting, content, frequency and duration. Future projects should strive for a standard set of assessment measures to identify patients eligible for pulmonary rehabilitation, taking disease complexity into consideration, which should result in referral to an appropriate rehabilitation setting. Local circumstances may complicate this crucial endeavour.

Pathobiological mechanisms underlying metabolic syndrome (MetS) in chronic obstructive pulmonary disease (COPD): clinical significance and therapeutic strategies

Chronic obstructive pulmonary disease (COPD) is a major incurable global health burden and is currently the 4th largest cause of death in the world. Importantly, much of the disease burden and health care utilisation in COPD is associated with the management of its comorbidities (e.g. skeletal muscle wasting, ischemic heart disease, cognitive dysfunction) and infective viral and bacterial acute exacerbations (AECOPD). Current pharmacological treatments for COPD are relatively ineffective and the development of effective therapies has been severely hampered by the lack of understanding of the mechanisms and mediators underlying COPD. Since comorbidities have a tremendous impact on the prognosis and severity of COPD, the 2015 American Thoracic Society/European Respiratory Society (ATS/ERS) Research Statement on COPD urgently called for studies to elucidate the pathobiological mechanisms linking COPD to its comorbidities. It is now emerging that up to 50% of COPD patients have metabolic syndrome (MetS) as a comorbidity. It is currently not clear whether metabolic syndrome is an independent co-existing condition or a direct consequence of the progressive lung pathology in COPD patients. As MetS has important clinical implications on COPD outcomes, identification of disease mechanisms linking COPD to MetS is the key to effective therapy. In this comprehensive review, we discuss the potential mechanisms linking MetS to COPD and hence plausible therapeutic strategies to treat this debilitating comorbidity of COPD.

Diabetes and Lung Disease: A Neglected Relationship

BACKGROUND

Diabetes mellitus is a systemic disorder associated with inflammation and oxidative stress which may target many organs such as the kidney, retina, and the vascular system. The pathophysiology, mechanisms, and consequences of diabetes on these organs have been studied widely. However, no work has been done on the concept of the lung as a target organ for diabetes and its implications for lung diseases.

AIM

In this review, we aimed to investigate the effects of diabetes and hypoglycemic agent on lung diseases, including asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, pulmonary hypertension, and lung cancer. We also reviewed the potential mechanisms by which these effects may affect lung disease patients.

RESULTS

Our results suggest that diabetes can affect the severity and clinical course of several lung diseases.

CONCLUSIONS

Although the diabetes-lung association is epidemiologically and clinically well-established, especially in asthma, the underlying mechanism and pathophysiology are not been fully understood. Several mechanisms have been suggested, mainly associated with the pro-inflammatory and proliferative properties of diabetes, but also in relation to micro- and macrovascular effects of diabetes on the pulmonary vasculature. Also, hypoglycemic drugs may influence lung diseases in different ways. For example, metformin was considered a potential therapeutic agent in lung diseases, while insulin was shown to exacerbate lung diseases; this suggests that their effects extend beyond their hypoglycemic properties.

PRISMA-compliant meta-analysis: association of metabolic syndrome and its components with the risk of chronic obstructive pulmonary disease

A preferred reporting items for systematic reviews and meta-analyses-compliant meta-analysis was conducted to test the association of metabolic syndrome and its components with the risk of chronic obstructive pulmonary disease (COPD) based on observational studies. Literature retrieval, article selection and data extraction were done by two researchers independently. Total 16 articles (20 independent studies) were analyzed with 3915 COPD patients and 25,790 control participants. Overall analysis indicated that metabolic syndrome was significantly associated with 1.53-fold (95% confidence interval [CI]: 1.23–1.9, P<0.001) increased risk of COPD, with moderate heterogeneity (I² = 74.3%). Of four metabolic components, hypertension was significantly associated with 1.55-fold (95% CI: 1.14–2.11, P=0.005) increased risk, and averaged levels of systolic blood pressure (weighted mean difference [WMD] = 3.626 mmHg, 95% CI: 1.537–5.714, P<0.001) and glucose (WMD = 2.976 mmol/l, 95% CI: 0.141–5.812; P=0.04) were significantly higher in COPD patients than in control participants, yet that of body mass index (WMD = −1.463 kg/m², 95% CI: −2.716 to −0.211, P=0.022) were significantly lower. Gender, race, source of control participants, matched status and sample size were identified as accountable factors for significant heterogeneity. Altogether, the presence of metabolic syndrome, especially its component hypertension, was associated with significantly increased risk of COPD.

Association between chronic obstructive pulmonary disease and serum lipid levels: a meta-analysis

Background

Metabolic syndrome is a common extrapulmonary comorbidity in patients with chronic obstructive pulmonary disease (COPD). However, the reported relationship of COPD with dyslipidemia, an important component of metabolic syndrome, is ambiguous. The aim of this meta-analysis is to investigate the association between COPD and the serum levels of high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), total cholesterol (TC), and triglyceride (TG).

Methods

The PubMed and Embase databases were searched to find potential studies using the search terms of (“dyslipidemia” or “HDL” or “LDL” or “cholesterol” or “triglyceride”) and COPD. We also performed subgroup analysis enrolling patients who were not receiving treatment for dyslipidemia. Mean differences (MD) with 95% confidence intervals (CI) were estimated with random effects models.

Results

A total of 11 studies comprising 615 cases and 471 controls were included in the study. No significant differences were found in the HDL (MD = −2.55, 95% CI [−6.03, 0.93], P = 0.15), LDL (MD = −2.25, 95% CI [−13.36, 8.86], P = 0.69), TC (MD = −2.69, 95% CI [−13.30, 7.92], P = 0.62), and TG (MD = 6.90, 95% CI [−2.81, 16.60], P = 0.16) levels of the 2 groups. However, subgroup analysis enrolling patients who were not receiving treatment for dyslipidemia showed that TG levels were higher in patients with stable COPD than in healthy individuals (MD = 16.35, 95% CI [5.90, 26.80], P = 0.002).

Conclusions

Excluding the impact of hypolipidemic treatment on serum lipid profile, TG levels were higher in patients with COPD than in healthy individuals. This meta-analysis suggested that physicians should screen COPD patients for elevated TG levels to reduce the risk of cardiovascular morbidity and mortality.

Ectopic adiposity and cardiometabolic health in COPD

Rationale

Obesity/overweight is the most prevalent body composition abnormality in COPD. However, little is known about the impact of fat distribution on cardiometabolic health in COPD.

Objective

To study the associations between ectopic adiposity, cardiometabolic health, and COPD.

Methods

A total of 263 subjects (166 males; age=65±9 years) were randomly selected from the general population. Subjects were classified as non-COPD controls and COPD, according to the Global initiative for chronic Obstructive Lung Disease (GOLD) classification, and the presence of cardiometabolic comorbidities was recorded. Ectopic fat accumulation was documented from computed tomography measurements of visceral adipose tissue cross-sectional areas and muscle mean attenuation, assessed at L4–L5. Blood glucose, lipid, and adipokine profiles were also evaluated.

Results

After correcting for age, sex, and tobacco exposure, visceral adipose tissue cross-sectional area was higher in GOLD 2+ compared to GOLD 1 individuals. Consistent with this, mean muscle tissue attenuation was lower in GOLD 2+ vs GOLD 1 and non-COPD controls (P<0.001). In multiple regression models, visceral adipose tissue cross-sectional area was strongly associated with hypertension (P<0.001) and diabetes (P<0.001), while muscle attenuation was associated with coronary artery disease (P<0.001). Blood glucose, lipid, and adipokine profiles were similar across groups with the exception of leptin level which was higher in GOLD 2+ subjects compared to GOLD 1 and controls.

Conclusion

GOLD 2+ COPD was associated with ectopic fat accumulation which modulated cardiometabolic health.

Obesity and Metabolic Abnormalities in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) and obesity are major causes of morbidity and mortality worldwide, and a relationship between COPD and obesity is increasingly recognized. The nature and underlying mechanisms of the link between obesity and COPD are still largely unknown. Obesity, and abdominal adiposity in particular, is linked to metabolic syndrome. Hypertension, hyperglycemia, and abdominal adiposity seem to be the most prevalent components of metabolic syndrome in COPD. Adipose tissues function as a source of a variety of signaling molecules in the pathobiology of respiratory diseases. Computed tomography allows measurement of various fat depots and allows better understanding of the impact of abdominal visceral fat in the pathophysiology of COPD. Innovative statistical methodology has identified obesity as a relevant and distinguishing characteristic in patients with COPD. Integrated research combining COPD and its multimorbidity network may unravel underlying endotypes to direct future interventions in this specific COPD cluster.

Relationship between airway obstruction and incidence of metabolic syndrome in Korea: a community-based cohort study

Background

Although studies have examined the relationship between metabolic syndrome (MetS) and COPD, the incidence of MetS in individuals with COPD has not specifically been investigated. This study aimed to evaluate the incidence of MetS in subjects with airway obstruction using data from a community-based cohort.

Patients and methods

Data representing 4 years of follow-up from the Ansung–Ansan cohort were analyzed; a total of 6,184 adults, who were ≥40 years of age and underwent spirometry, were enrolled in this study. Airway obstruction was defined as forced expiratory volume in 1 s/forced vital capacity ratio <70%, and MetS was determined according to the National Cholesterol Education Program Adult Treatment Panel III guidelines.

Results

A total of 419 patients were newly diagnosed with MetS, based on the National Cholesterol Education Program Adult Treatment Panel III guidelines, during follow-up. MetS was more frequent in COPD subjects, relative to non-COPD subjects, in both sexes (14.7% vs 11.0% [men] and 14.7% vs 11.8% [women]). In men subjects, the risk for MetS was higher in subjects with airflow obstruction than in subjects without obstruction, after adjusting for age, body mass index, and smoking status.

Conclusion

The incidence of MetS was higher in men with airflow obstruction than in healthy subjects.

Obesity and metabolic syndrome in COPD: Is exercise the answer?

Approximately half of all patients with chronic obstructive pulmonary disease (COPD) attending pulmonary rehabilitation (PR) programmes are overweight or obese which negatively impacts upon dyspnoea and exercise tolerance particularly when walking. Within the obese population (without COPD), the observed heterogeneity in prognosis is in part explained by the variability in the risk of developing cardiovascular disease or diabetes (cardiometabolic risk) leading to the description of metabolic syndrome. In obesity alone, high-intensity aerobic training can support healthy weight loss and improve the constituent components of metabolic syndrome. Those with COPD, obesity and/or metabolic syndrome undergoing PR appear to do as well in traditional outcomes as their normal-weight metabolically healthy peers in terms of improvement of symptoms, health-related quality of life and exercise performance, and should therefore not be excluded. To broaden the benefit of PR, for this complex population, we should learn from the extensive literature examining the effects of exercise in obesity and metabolic syndrome discussed in this review and optimize the exercise strategy to improve these co-morbid conditions. Standard PR outcomes could be expanded to include cardiometabolic risk reduction to lower future morbidity and mortality; to this end exercise may well be the answer.

Prioritizing chronic obstructive pulmonary disease (COPD) candidate genes in COPD-related networks

Chronic obstructive pulmonary disease (COPD) is a multi-factor disease, which could be caused by many factors, including disturbances of metabolism and protein-protein interactions (PPIs). In this paper, a weighted COPD-related metabolic network and a weighted COPD-related PPI network were constructed base on COPD disease genes and functional information. Candidate genes in these weighted COPD-related networks were prioritized by making use of a gene prioritization method, respectively. Literature review and functional enrichment analysis of the top 100 genes in these two networks suggested the correlation of COPD and these genes. The performance of our gene prioritization method was superior to that of ToppGene and ToppNet for genes from the COPD-related metabolic network or the COPD-related PPI network after assessing using leave-one-out cross-validation, literature validation and functional enrichment analysis. The top-ranked genes prioritized from COPD-related metabolic and PPI networks could promote the better understanding about the molecular mechanism of this disease from different perspectives. The top 100 genes in COPD-related metabolic network or COPD-related PPI network might be potential markers for the diagnosis and treatment of COPD.

Metabolic syndrome and Chronic Obstructive Pulmonary Disease (COPD): The interplay among smoking, insulin resistance and vitamin D

Background

A close relationship between Metabolic Syndrome (MetS) and Chronic Obstructive Pulmonary Disease (COPD) has been described, but the exact nature of this link remains unclear. Current epidemiological data refer exclusively to the MetS prevalence among patients with COPD and data about the prevalence of COPD in MetS patients are still unavailable.

Aim of the study

To analyse and compare risk factors, clinical and metabolic characteristics, as well as the main respiratory function parameters, among patients affected by MetS, COPD or both diseases.

Patients

We recruited 59 outpatients with MetS and 76 outpatients with COPD. After medical history collection, physical examination, blood sampling for routine analysis, spirometric evaluation, they were subdivided into MetS (n = 46), MetS+COPD (n = 60), COPD (n = 29).

Results

A MetS diagnosis was assigned to 62% of COPD patients recruited in the COPD Outpatients Clinic of the Pneumology Department, while the COPD prevalence in MetS patients enrolled in the Internal Medicine Metabolic Disorders Outpatients Clinic was 22%. More than 60% of subjects enrolled in each Department were unaware that they suffered from an additional disease. MetS+COPD patients exhibited significantly higher C-peptide levels. We also found a positive relation between C-peptide and pack-years in all subjects and a negative correlation between C-peptide and vitamin D only in current smokers. Finally, a negative association emerged between smoking and vitamin D.

Conclusions

We have estimated, for the first time, the COPD prevalence in MetS and suggest a potential role of smoking in inducing insulin resistance. Moreover, a direct effect of smoking on vitamin D levels is proposed as a novel mechanism, which may account for both insulin resistance and COPD development.

Increased risk of chronic obstructive pulmonary disease in patients with bipolar disorder: A population-based study

BACKGROUND

We conducted this nationwide study to examine the prevalence and incidence of chronic obstructive pulmonary disease (COPD) among patients with bipolar disorder in Taiwan.

METHODS

We used a random sample of 766,427 subjects who were aged ≥18 years in 2005. Patients with at least one primary diagnosis of bipolar disorder were identified. Study participants with one primary or secondary diagnosis of COPD for either ambulatory or inpatient care were also identified. We compared the prevalence of COPD in patients with bipolar disorder and the general population in 2005. In addition, we further investigated this cohort from 2006 to 2010 to detect incident cases of COPD in patients with bipolar disorder compared with the general population. The factors associated with COPD among patients with bipolar disorder were also analyzed.

RESULTS

The prevalence of COPD in patients with bipolar disorder was higher than in the general population in 2005 (5.68% vs. 2.88%, odds ratio 2.03; 95% confidence interval, 1.53-2.67). The average annual incidence of COPD in patients with bipolar disorder was also higher than in the general population (2.03% vs. 1.03%, risk ratio 1.94; 95% confidence interval, 1.65-2.29) from 2006 to 2010.

LIMITATIONS

Some risk factors for COPD such as substance use, obesity, or lifestyle pattern were not available in this study.

CONCLUSIONS

Patients with bipolar disorder had a higher prevalence and incidence of COPD compared with the general population. Higher prevalence of COPD among bipolar patients was associated with increased age, males, hypertension, and second-generation antidepressant use.

Chronic obstructive pulmonary disease candidate gene prioritization based on metabolic networks and functional information

Chronic obstructive pulmonary disease (COPD) is a multi-factor disease, in which metabolic disturbances played important roles. In this paper, functional information was integrated into a COPD-related metabolic network to assess similarity between genes. Then a gene prioritization method was applied to the COPD-related metabolic network to prioritize COPD candidate genes. The gene prioritization method was superior to ToppGene and ToppNet in both literature validation and functional enrichment analysis. Top-ranked genes prioritized from the metabolic perspective with functional information could promote the better understanding about the molecular mechanism of this disease. Top 100 genes might be potential markers for diagnostic and effective therapies.

Cardiovascular comorbidity in patients with chronic obstructive pulmonary disease in the Canary Islands (CCECAN study)

INTRODUCTION

Numerous studies have shown a high prevalence of cardiovascular disease in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to analyse the prevalence of cardiovascular risk factors and comorbidity in a Canary Islands population diagnosed with COPD, and compared it with data from the general population.

PATIENTS AND METHODS

A cross-sectional study was carried out in 300 patients with COPD and 524 subjects without respiratory disease (control group). The two groups were compared using standard bivariate methods. Logistic regression models were used to estimate the cardiovascular risks in COPD patients compared to control group.

RESULTS

Patients with COPD showed a high prevalence of hypertension (72%), dyslipidaemia (73%), obesity (41%), diabetes type 2 (39%), and sleep apnoea syndrome (30%) from mild stages of the disease (GOLD 2009). There was a 22% prevalence of cardiac arrhythmia, 16% of ischaemic heart disease, 16% heart failure, 12% peripheral vascular disease, and 8% cerebrovascular disease. Compared to the control group, patients with COPD had a higher risk of dyslipidaemia (OR 3.24, 95% CI; 2.21-4.75), diabetes type 2 (OR 1.52, 95% CI; 1.01-2,28), and ischaemic heart disease (OR 2.34, 95% CI; 1.22-4.49). In the case of dyslipidaemia, an increased risk was obtained when adjusted for age, gender, and consumption of tobacco (OR 5.04, 95% CI; 2.36-10.74).

CONCLUSIONS

Patients with COPD resident in the Canary Islands have a high prevalence of hypertension, dyslipidaemia, ischaemic heart disease, and cardiac arrhythmia. Compared to general population, patients with COPD have a significant increase in the risk of dyslipidaemia.

The Prevalence of Diabetes Mellitus in COPD Patients with Severe and Very Severe Stage of the Disease

AIM

The aim of the study was to investigate the prevalence of diabetes mellitus in privies diagnosed chronic obstructive pulmonary disease (COPD) patients with severe and very severe disease, which ware stable.

METHODS

We investigated 100 subjects, all of them smokers, with smoking status >10 years. They were stratified in two groups. It was clinical, randomized, cross sectional study. Besides demographic parameters, functional parameters, BMI, cholesterol, LDL and HDL, and the level of blood sugar was measured.

RESULTS

The prevalence of diabetes mellitus in our survey in total number of COPD patients with severe and very severe stage was 21%. In the very severe group were recorded significantly higher average values of glycaemia compared with severe group (7.67 ± 3.7 vs. 5.62 ± 0.9, p = 0.018). In the group with severe COPD, it was not confirmed any factor with significant predictive effect on the values of glycaemia. As independent significant factors that affect blood glucose in a group of very severe COPD were confirmed cholesterol (p <0.0001) and HDL (p = 0.018).

CONCLUSION

These results suggest that the presence of the COPD in patients itself is a factor that results in the clinical presentation of diabetes mellitus Type 2.

The Level of Cholesterol in COPD Patients with Severe and Very Severe Stage of the Disease

BACKGROUND

High blood cholesterol is part of metabolic syndrome and can be caused by medical conditions or bad dietary habits.

AIM

The aim of the study was to investigate the prevalence of hypercholesterolemia in privies diagnosed patients with the severe and very severe stage of COPD, which were stable.

MATERIAL AND METHODS

We investigated 100 subjects, all of them smokers, with smoking status >10 years, stratified into two groups: with severe and very severe stage of the disease. It was clinical, randomized, cross-sectional study. Besides demographic parameters and functional parameters, body mass index, cholesterol, LDL, and HDL were investigated.

RESULTS

In the group of patients with very severe COPD were recorded significantly higher average values of cholesterol (6.16 ± 1.5 vs. 5.61 ± 1.1, p = 0.039). As independent significant factors influencing cholesterol in the group with a very severe COPD were confirmed the age of the patients (p = 0.005), LDL (p = 0.004) and HDL (p = 0.002). In the group with severe COPD, only LDL was confirmed as an independent significant factor that has an impact on cholesterol (p < 0.0001).

CONCLUSION

The results of our survey demonstrated a high level of blood cholesterol and LDL, and low level of blood HDL in both investigated group's patients with COPD.

Management of chronic obstructive pulmonary disease beyond the lungs

Chronic obstructive pulmonary disease (COPD) is an umbrella term that covers many clinical subtypes with clearly different pulmonary and extra-pulmonary characteristics, but with persistent airflow limitation in common. This insight has led to the development of a more personalised approach in bronchodilator therapy, prevention of exacerbations, and advanced treatments (such as non-invasive ventilation and lung volume reduction techniques). However, systemic manifestations and comorbidities of COPD also contribute to different clinical phenotypes and warrant an individualised approach as part of integrated disease management. Alterations in bodyweight and composition, from cachexia to obesity, demand specific management. Psychological symptoms are highly prevalent, and thorough diagnosis and treatment are necessary. Moreover, prevention of exacerbations requires interventions beyond the lungs, including treatment of gastro-oesophageal reflux disease, reduction of cardiovascular risks, and management of dyspnoea and anxiety. In this Review, we discuss the management of COPD beyond the respiratory system and propose treatment strategies on the basis of the latest research and best practices.

Relationship between metabolic syndrome and epicardial fat tissue thickness in patients with chronic obstructive pulmonary disease

OBJECTIVE

An increase in epicardial fat tissue (EFT) thickness was found to be associated with metabolic syndrome (MS) and ischemic heart disease. MS is a comorbidity of chronic obstructive pulmonary disease (COPD) resulting from the accompanying systemic inflammation. The aim of our study was to investigate the usefulness of EFT thickness to predict MS in COPD patients.

METHODS

COPD patients admitted to our clinic during January-December 2014 and healthy controls were included in this prospective case control study. Patients with comorbidities, COPD exacerbation, and malignancies were excluded. Patients and controls were compared in terms of anthropometric measurements, MS-related examination and laboratory findings, pulmonary function tests, and EFT thickness. The correlations between EFT thickness and markers of MS in COPD were evaluated using the Student's t-test and logistic regression analysis.

RESULTS

COPD patients and controls were composed of 82 and 84 individuals, respectively. MS was diagnosed in 31 (37.8%) COPD patients. The EFT thickness was significantly higher in COPD patients than in the controls and was also higher in COPD patients with MS than in those without MS (all p<0.001). Each 1-mm increment of EFT raised the risk of MS two-fold (p=0.011, OR=2.08, 95% CI: 1.18-3.68). Increase in triglyceride level (p=0.004, OR=1.02, 95% CI: 1.01-1.03) and reduction in forced vital capacity (p=0.025, OR=0.26, 95% CI: 0.08-0.84) were found to be associated with increased MS risk. The cut-off value for EFT thickness in the prediction of MS in COPD patients was 6.75 mm (sensitivity: 83%, specificity: 65%).

CONCLUSION

EFT thickness is a non-invasive and easily available parameter, which is valuable in the prediction of increased MS risk in COPD patients. Early diagnosis of patients at risk of MS may help to prevent ischemic heart disease in these patients.

Metabolic syndrome in patients with chronic obstructive pulmonary disease: frequency and relationship with systemic inflammation

BACKGROUND

Metabolic syndrome (MetS) is frequent in patients with chronic obstructive pulmonary disease (COPD). Systemic inflammation plays an important role in both COPD and MetS. The aim of this study was to assess the frequency of MetS in COPD patients and to evaluate the status of systemic inflammation in COPD patients with MetS and those without MetS.

METHODS

This cross-sectional study included 98 consecutive stable COPD patients. The MetS was defined using the criteria of the International Diabetes Federation. Components of MetS and markers of systemic inflammation: C-reactive protein (CRP), fibrinogen, and leukocyte count were measured. All patients underwent spirometry. The staging of COPD was made according to the Global initiative for chronic obstructive lung disease (GOLD) criteria.

RESULTS

MetS was present in 37.8 % COPD patients. The frequencies of MetS in patients with GOLD stages I, II, III, and IV were 33.3 %, 48.8 %, 31.6 %, and 23.1 %, respectively. MetS frequencies were not significantly different between GOLD stages. The multivariate logistic regression analysis revealed leukocyte count and CRP level as significant independent predictors of the presence of Mets in COPD patients (OR =1.321, 95%CI: 1.007-1.628, p =0.009 and OR =1.184, 95%CI: 1.020-1.376, p =0.027 respectively).

CONCLUSIONS

This study shows that MetS is frequent in patients with COPD. Systemic inflammatory markers are higher in COPD patients with MetS than in patients without MetS. These findings suggest that physicians should screen COPD patients for associated MetS and elevated circulatory inflammatory markers. Management of these disorders should reduce the risk of cardiovascular morbidity and mortality in these patients. Hippokratia 2016, 20(2):110-114.

Chronic obstructive pulmonary disease is not a risk factor for polyneuropathy: A prospective controlled study

Polyneuropathy has been observed in patients with chronic obstructive pulmonary disease (COPD). If polyneuropathy occurs as a complication or extrapulmonary manifestation of COPD, one would expect an increased prevalence among patients with a cryptogenic axonal polyneuropathy. This case-control study aimed to investigate the association between COPD and polyneuropathy. We prospectively included 345 patients with cryptogenic axonal polyneuropathy and 465 controls. A standardized questionnaire assessed the presence of COPD and we verified this diagnosis by contacting the family physician. The severity of COPD was based on the Global Initiative for Chronic Obstructive Lung Disease classification. The prevalence of COPD did not differ between patients with polyneuropathy and controls (15/345 vs. 12/465 respectively; odds ratio (OR) 1.7; 95% confidence interval (CI) [0.8-3.7]). Adjusting for age, gender and possible confounders did not affect these results (adjusted OR 1.7, 95% CI 0.7-4.1). The severity of COPD was similar between patients with polyneuropathy and controls. This study does not support the hypothesis that COPD is a risk factor for polyneuropathy.

Metabolic Syndrome and the Lung

A link between metabolic syndrome (MetS) and lung diseases has been observed in several cross-sectional and longitudinal studies. This syndrome has been identified as an independent risk factor for worsening respiratory symptoms, greater lung function impairment, pulmonary hypertension, and asthma. This review will discuss several potential mechanisms to explain these associations, including dietary factors and the effect of adiposity and fat-induced inflammation on the lungs, and the role of other comorbidities that frequently coexist with MetS, such as OSA and obesity. In contrast to the well-known association between asthma and obesity, the recognition that MetS affects the lung is relatively new. Although some controversy remains as to whether MetS is a unique disease entity, its individual components have independently been associated with changes in pulmonary function or lung disease. There is, however, uncertainty as to the relative contribution that each metabolic factor has in adversely affecting the respiratory system; also, it is unclear how much of the MetS-related lung effects occur independently of obesity. In spite of these epidemiological limitations, the proposed mechanistic pathways strongly suggest that this association is likely to be causal. Given the wide prevalence of MetS in the general population, it is imperative that we continue to further understand how this metabolic disorder impacts the lung and how to prevent its complications.

Implications of the inflammatory response for the identification of biomarkers of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by both local and systemic inflammation. Because inflammation plays a critical role in the development, course and severity of COPD, inflammatory markers have the potential to improve the current diagnostic and prognostic approaches. Local inflammation in COPD is characterized by an infiltration of inflammatory cells, with an increased expression of cytokines, chemokines, enzymes, growth factors and adhesion molecules. Systemic low-grade inflammation is another common but nonspecific finding in COPD. Exacerbations of COPD are acute clinical events accompanied by an exaggerated inflammatory response. Future investigations in the field of COPD biomarkers should take into account different study designs and biochemical assays, disease course and duration, variations in symptom severity and timing of measurement.

Impact of overlap syndrome on severity of acute exacerbation of chronic obstructive pulmonary disease

BACKGROUND

The severity of exacerbation in chronic obstructive pulmonary disease (COPD) due to the overlap of obstructive sleep apnea syndrome (OSAS) is not known.

AIMS

To find out the 1) severity of acute exacerbation of COPD (AECOPD) in patients with overlap syndrome compared to only COPD, 2) prevalence of overlap syndrome in AECOPD, and 3) clinical characteristics of COPD compared to overlap syndrome.

MATERIALS AND METHODS

Fifty-one patients admitted with AECOPD were classified into; Mild exacerbation: Normal arterial blood gases (ABG) treated with antibiotics, Moderate: Normal ABG treated with parenteral corticosteroids, Severe: Type 1 respiratory failure, Very severe: Type 2 respiratory failure with normal pH and Life-threatening: Type 2 respiratory failure with pH <7.35. They were evaluated for OSAS with full polysomnography after the exacerbation subsided and analysed depending on presence or absence of overlap syndrome.

RESULTS

The majority of only COPD cases (26/38) had mild and moderate exacerbations whereas majority of overlap patients (9/13) had severe, very severe and life-threatening exacerbations (statistically significant, P = 0.021). Of 51 patients, 13 had OSAS i.e. the prevalence of overlap in AECOPD was 25.5%. The mean BMI in only COPD and overlap syndrome was 20.70 ± 8.03 kg/m(2) and 31.82 ± 5.80 kg/m(2) (P < 0.001), respectively. Metabolic syndrome was recorded in 2/36 (5.3%) patients in only COPD and 6/13 (46.2%) patients in overlap (P < 0.001).

CONCLUSION

Overlap syndromes are more likely have respiratory failure compared to only COPD during AECOPD. AECOPD have a high prevalence of OSAS. Overlap syndrome have significantly higher likelihood of obesity and metabolic syndrome compared to only COPD.

Prevalence of metabolic syndrome in patients with pulmonary hypertension

BACKGROUND AND AIMS

To determine the prevalence of metabolic syndrome (MetS) - a potential phenotypical risk for pulmonary hypertension (PH) - in patients with PH and by PH diagnostic group including group 1 pulmonary arterial hypertension (PAH); group 1.1 idiopathic PAH, groups 1.2 heritable PAH, 1.3 drug and toxin induced, 1.4 associated PAH, group 2 PH with left heart disease, group 3 PH associated with lung disease and/or hypoxemia, group 4 PH owing to chronic thrombotic and/or embolic disease, and group 5 PH from multifactorial mechanisms.

METHODS

We conducted a retrospective chart review of patients referred to Mayo Clinic in Florida from January 1990 to October 2013 (N = 1287). Only patients whom PH was confirmed by right heart catheterization were included (N = 640). MetS was defined with at least three of the following: systemic hypertension, diabetes mellitus, hyperlipidemia and body mass index > 30.

RESULTS

MetS was prevalent in 247 of 640 (39%) with PH: 13% in group 1.1 PAH, 12% in groups 1.2-1.4 PAH, 54% in group 2, 55% in group 3, 23% in group 4 and 24% in group 5. After adjusting for age, sex and race, diagnostic subgroup analysis revealed a higher prevalence of MetS in WHO Group 2 PH patients [adjusted odd ratios (OR): 2.58, P < 0.0001] and WHO group 3 PH (adjusted OR: 2.77, P < 0.0001) when compared to group 1 PH.

CONCLUSION

The prevalence of MetS was observed in 39% of patients with PH; however, among PH patients, the prevalence was higher in group 2 and 3 PH.

Relationship Between Forced Vital Capacity and Framingham Cardiovascular Risk Score Beyond the Presence of Metabolic Syndrome: The Fourth Korea National Health and Nutrition Examination Survey

Impaired lung function is a risk factor for cardiovascular (CV) events. However, it has not been well established whether FVC reduction even within normal range is associated with cardiovascular disease (CVD) risk and whether reduced FVC is an independent relationship of CVD irrespective of metabolic syndrome. Thus, we aimed to explore the relationship between FVC and CV-event risk using the FRS beyond the presence of metabolic syndrome or abdominal obesity in a representative Korean population based on data from the nationwide Korea National Health and Nutrition Examination Survey (KNHANES IV).The study population included 9688 subjects ≥ 30 years of age with no previous diagnosis of CVD and obstructive lung disease. Using a logistic regression model and area under the curve (AUC) analysis, we evaluated the relationship between FVC quintiles and CV-event risk using the Framingham Risk Score (FRS; ≥ 10% or ≥ 20%). In addition, we examined the effect of FVC on CV-event risk based on the presence of metabolic syndrome (MetS) and abdominal obesity.After adjusting for covariates, comparison of subjects in the lowest FVC (% pred) quintile (Q1) with those in the highest quintile (Q5) yielded an odds ratio (OR) of 2.27 (95% CI, 1.91-2.71) for intermediate and high risk, and 2.89 (95% CI, 2.31-3.61) for high risk. The ORs for cardiovascular risk using FRS also increased irrespective of the presence of abdominal obesity and MetS without significant interaction. Furthermore, the addition of FVC status to MetS status and abdominal obesity status significantly increased the AUC of the model predicting CV-event risk (P < 0.001 and P < 0.001).Our study demonstrates that FVC is inversely associated with 10-year CV-event risk, irrespective of MetS and abdominal obesity in the general population without obstructive lung disease. Furthermore, the addition of FVC to MetS or abdominal obesity increased prediction of CVD event risks, implying a potential role of FVC to predict CV events.

Comparison of frequency of insulin resistance in patients with chronic obstructive pulmonary disease with normal controls

OBJECTIVE

To compare mean homeostatic model assessment of insulin resistance (HOMA-IR) in patients with and without chronic obstructive pulmonary disease (COPD).

METHODS

A Case control analytic study was conducted in medical outpatient department of Medial Unit-II of Dow University of Health Sciences from April 2013 to September 2013. All patients with the diagnosis of COPD were included as cases. Controls were age match healthy individuals with minor illnesses. Age, weight, height and forced expiratory volume in one second to forced vital capacity (FEV1/FVC) ratio were documented. Fasting blood glucose and fasting insulin levels were done. Body mass index (BMI) and IR was calculated using the formulas. HOMA-IR was compared between cases and controls.

RESULTS

Forty COPD patients were compared with thirty five age match controls. HOMA-IR was found to be higher in cases as compared to controls (2.85 v/s 2.00) with a p value <0.000.

CONCLUSION

COPD is one of the chronic debilitating diseases in our region with various extra-pulmonary complications. We found IR to be present higher in COPD patients compared with healthy controls. Evaluating the pulmonary function as well as systemic metabolic parameters, may contribute to minimizing mortality and morbidity.

The chronic obstructive pulmonary disease comorbidity spectrum in Japan differs from that in western countries

Patients with Chronic Obstructive Pulmonary Disease (COPD) frequently suffer from various comorbidities, such as cardiovascular disease, osteoporosis, depression, malnutrition, metabolic syndrome, diabetes, and lung cancer. These comorbidities have a significant impact on disease severity and survival. In fact, guidelines from both the Global Initiative for Chronic Obstructive Lung Disease and the Japanese Respiratory Society recommend that physicians take comorbidities into account when they evaluate COPD severity. These guidelines also emphasize the importance of managing comorbidities alongside airway obstruction in COPD. The mechanisms by which the many COPD-related comorbidities develop are still unclear. Aging and smoking are well-established as major factors. However, systemic inflammation may also contribute to the disease process. Having developed from the classical theory to differentiate COPD patients into "pink puffers" and "blue bloaters", COPD is now generally considered as a heterogeneous condition. On this point, we have noticed that the characteristics of Japanese COPD patients tend to differ from those of Westerners. Specifically, Japanese patients tend to be older, to have lower body mass index, to suffer from emphysema-dominant lung disease, and to experience exacerbations less frequently. The comorbidity spectrum of Japanese COPD patients also seems to differ from that of Westerners. For instance, in Japanese patients, cardiovascular disease and metabolic syndrome are less prevalent, whereas osteoporosis and malnutrition are more frequent. In order to treat Japanese COPD patients optimally, we must pay particular attention to their unique demographics and comorbidity spectrum, which contrast with those of Western COPD patients.

Vitamin D deficiency and airflow limitation in the Baltimore Longitudinal Study of Ageing

BACKGROUND

Vitamin D deficiency is common in patients with chronic obstructive pulmonary disease (COPD) and has also been linked to comorbidities often present in COPD.

AIM

The aim of this study was to investigate whether vitamin D deficiency was related specifically to airflow limitation or whether vitamin D deficiency was determined by conditions that frequently coexist with COPD: insulin resistance, hypertension, anaemia, obesity and hypercholesterolaemia.

METHODS

For this cross-sectional analysis, we included 897 subjects from the Baltimore Longitudinal Study of Aging. Subjects taking vitamin D supplements were excluded. Airflow limitation was defined as FEV1 /FVC < lower limit of normal. Logistic regression was used to assess the association between vitamin D deficiency (25-hydroxy vitamin D < 20 ng/mL) and possible determinants.

RESULTS

Vitamin D deficiency was not specific for subjects with airflow limitation. Body mass index (BMI) (OR: 1.05, P < 0.03) and obesity (BMI > 30 kg/m(2)) (OR: 1.9, P < 0.002) were significantly associated with vitamin D deficiency in the adjusted multivariate regression analysis. Physical activity was associated with a decreased risk of vitamin D deficiency.

CONCLUSIONS

Airflow limitation was not an independent determinant of vitamin D deficiency. The effect of weight loss and increased physical activity on vitamin D levels should be investigated further in intervention studies.

Comorbidities and Chronic Obstructive Pulmonary Disease: Prevalence, Influence on Outcomes, and Management

Comorbidities impact a large proportion of patients with chronic obstructive pulmonary disease (COPD), with over 80% of patients with COPD estimated to have at least one comorbid chronic condition. Guidelines for the treatment of COPD are just now incorporating comorbidities to their management recommendations of COPD, and it is becoming increasingly clear that multimorbidity as well as specific comorbidities have strong associations with mortality and clinical outcomes in COPD, including dyspnea, exercise capacity, quality of life, healthcare utilization, and exacerbation risk. Appropriately, there has been an increased focus upon describing the burden of comorbidity in the COPD population and incorporating this information into existing efforts to better understand the clinical and phenotypic heterogeneity of this group. In this article, we summarize existing knowledge about comorbidity burden and specific comorbidities in COPD, focusing on prevalence estimates, association with outcomes, and existing knowledge about treatment strategies.