Association between left ventricular diastolic dysfunction and severity of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major cause of chronic morbidity and mortality throughout the world. According to global initiative for chronic obstructive lung disease, COPD is defined as FEV1/FVC<70% by spirometry. COPD affects pulmonary blood vessels, right ventricle as well as left ventricle, leading to development of pulmonary hypertension, cor-pulmonale, right ventricular dysfunction as well as left ventricular dysfunction. The significance of the right ventricular performance is recognized as one of the factors determining the clinical course and prognosis in COPD, but a potential role of the left ventricle is, however, less studied. The aim of this study was primarily to evaluate left ventricular function in COPD patients by echocardiography and to study the correlation between echocardiography findings and the severity of COPD based on GOLD1 criteria. A total of 100 patients were selected for this study, including 72 male patients and 28 female patients, aged 50–70 years, from outpatient department of medicine department, medical wards, TB and chest ward of Dr Baba Sahib Ambedkar Hospital, Delhi, considering the exclusion and inclusion criteria. In mild COPD group, only one patient was found to have systolic dysfunction out of 52 patients (1.92%), in moderate COPD group, 2 patients had systolic dysfunction out of 32 patients (6.25%), whereas in severe COPD, six patients had systolic dysfunction out of 16 patients (37.5%). So, in total, 9% patients had systolic dysfunction. 28% of patients were found to have left ventricular diastolic dysfunction in our study. COPD patients have a high prevalence of left ventricular diastolic dysfunction, which is associated with disease severity. A clear correlation was found between value of fractional shortening (FS) of left ventricle (a measure of contractility), and severity of COPD and FS value significantly decreased as the severity of COPD increased. In this study, ejection fraction (EF) was found to be preserved in mild and moderate COPD, albeit mean EF was found to be reduced in moderate COPD. In severe COPD group, EF was significantly lowered.

Left ventricular diastolic dysfunction in patients with chronic obstructive pulmonary disease (COPD), prevalence and association with disease severity: Using tissue Doppler study

Chronic obstructive pulmonary disease (COPD) results from a complex interaction between genes and the environment, and occupational exposures are an underappreciated risk factor. Until now, little research attention has been paid to the potential impact of occupational risk factor exposure on the COPD in China. The aim of this retrospective study was to analyze the role of occupational risk factor exposure on the severity and progression of COPD for exploring new prevention strategies for this disease. This study adopted a random cluster-sampling method. Five grade-A tertiary hospitals that met the inclusion criteria were selected as the survey sites, and patients with COPD hospitalized in these hospitals from January 1, 2019, to December 31, 2019, were selected as the research subjects. Data of the patients diagnosed with COPD met the Global Initiative for Chronic Obstructive Lung Disease (2019) criteria and were collected from the computerized medical record databases. Among 4082 investigated COPD patients, 1063 (26%) were found to have occupational risk factor exposure history. The top 3 industries with a large COPD case number and a history of occupational risk factor exposure ranked in the order of agriculture (including farming, forestry, animal husbandry, and fishery), manufacturing, and mining. Further multivariate logistic regression analysis indicated that when setting a low exposure level as a reference, medium and high exposure levels were correlated with the severity of COPD (odds ratio values were 2.837 and 6.201, respectively, P < .05). Linear regression analysis showed that cumulative exposure to occupational risk factors was negatively correlated with the forced expiratory volume in 1-second percentage of COPD patients, with a correlation coefficient of 0.68. Our results indicated that occupational risk factor exposure levels were related to the severity of COPD significantly. The incubation period of COPD in the exposure group was significantly shorter than that in the non-exposure group. To prevent worked-related COPD, special attention and control efforts should be taken to reduce the level of occupational risk factors such as organic dust, irritating chemicals, etc in the work environments, especially in the industries of agriculture, forestry, animal husbandry and fishery, manufacturing, and mining.

Cause-specific mortality adjudication in the UPLIFT® COPD trial: Findings and recommendations

The Yin and Yang of dyspnea in the emergency department: heart failure or COPD?

Comorbidity of chronic obstructive pulmonary disease (COPD) and cardiovascular disease (CVD) is currently important and not fully investigated. The aim of this study was to analyze clinical signs, lung function, the central and the intracardiac hemodynamics, and predictors of outcome in patients with comorbidity of COPD and CVD. Methods. The study involved 118 patients with stage 3 to 4 COPD (GOLD, 2016) including 111 men and 7 women. The mean age was 59.5 ± 0.63 years, the smoking history was 23.1 ± 0.93 pack-years, and body mass index (BMI) was 27.2 ± 9.06 kg/m2. The patients were allocated into one of three groups: COPD group (n = 37), COPD + coronary heart disease (CHD) group (stable angina functional class (FC) II to III, n = 45), and COPD + hypertension (H) group, n = 36). Results. Patients with COPD and CVD were older, had higher smoking history and higher BMI. Clinical signs of COPD were more prominent and the lung function was lower in COPD patients with CVD comorbidity. Cardiac remodeling and right and left ventricular diastolic dysfunction were more severe in the groups with comorbidity. The 3-year survival in the groups with comorbidity clearly tended to be lower. Age, smoking history, the heart beat rate, the systolic blood pressure, the distance in 6-minute walking test, and the serum C-reactive protein and fibrinogen levels were independent predictors of mortality in both COPD + CHD and COPD + H groups. Conclusion. The comorbidity of COPD + CHD and COPD + H is characterized by more severe clinical signs and symptoms of COPD, and decreased physical tolerance. Hypoxemia, heart remodeling, left and right ventricular diastolic dysfunction, and higher mortality risk were seen in both groups with comorbidity.

Chronic obstructive pulmonary disease (COPD) is an inflammatory systemic disorder that affects the respiratory tract airways and breathing. Left ventricular diastolic dysfunction (LVDD), which is the inability of the ventricle to fill to a normal end-diastolic volume, may be observed in patients with severe COPD. This study aimed to evaluate LVDD in patients with COPD. This cross-sectional study included 58 patients under 65 years of age with COPD as the case group. Moreover, 58 patients with normal spirometry and without pulmonary or cardiac disease were included as the control group. They referred to the cardiologist for echocardiography. Patients were tested for C-reactive protein (CRP) and N-terminal pro-B-type natriuretic peptides (NT -pro BNP). Data were analyzed with SPSS for descriptive reports of the relationship between variables. The results showed that LVDD was significantly higher in COPD patients (60%) than in the control group (12.2%). Also, there was no significant relationship between LVDD and BMI in COPD patients. Evaluation of CRP and PRO-BNP showed that the distribution of patients in different diastolic function classes is similar. It was observed that with increasing COPD severity, LVDD severity increased (p-value =0.101). There is a direct relationship between total lung capacity (TLC) and LVDD (P-value <0.0001). In COPD patients, there was a significant relationship between diastolic function and SPAP (P-value <0.0019). In general, it should be noted that the prevalence of LVDD in patients with COPD is significantly higher than in other people.

Bronchodilatory effects of NVA237, a once daily long-acting muscarinic antagonist, in COPD patients

Impulse oscillation system versus spirometry in assessment of obstructive airway diseases

Objective To discuss the characteristics of cardiopulmonary exercise test(CPX) and its value in the evaluation of status in the patients with Chronic obstructive pulmonary disease (COPD). Methods Forty two male patients with stable COPD as the test group and thirty one healthy men were respectively measured pulmonary function test (PFT), CPX and 6 minute walking test (6MWT), and the COPD group were recorded the modified Medical Research Council (mMRC). The comparation of the two groups in the index of PFT, CPX and 6MWT were analyzed, meanwhile in the COPD group the correlation between the index of CPX and PFT, 6MWT and mMRC were also measured.All these were summarized to evaluate the value of CPX in patients with COPD. Results ①In COPD group, the forced expiratory volume in 1st second (FEV1), forced expiratory volume in 1st second/forced vital capacity (FEV1/FVC) and the ratio of FEV1 in predicted value (FEV1%pred) were lower than the control group (P<0.01). Maximal work rate (Wmax), maximal oxygen uptake(VO2max), the ratio of maximal oxygen uptake to weight (VO2max/kg), oxygen pulse (O2 pulse), anaerobic threshold (AT), maximal exercise ventilation (VEmax), and breathing reserve(BR) of COPD group were all lower than the control group (P<0.01). The heart rate reserve(HRR), ventilatory equivalent of carbon dioxide(VE/VCO2) in COPD group were higher than the control group (P<0.05). ②In COPD patients, the Wmax, VEmax and FVC, FEV1, FEV1%pred were revealed a moderate positive correlation (P<0.01), and the VO2max and FVC, FEV1 were also characterised a moderate positive correlation (P<0.01), conversely the AT was weakly positive correlated with FEV1 (P<0.05), while PFT's ventilation index had no correlation with the O2 pulse, VE/VCO2 and BR.③The CPX classification and PFT classification had poor consistency (Kappa=0.076, P=0.097). ④In COPD patients the Wmax was negatively correlated with mMRC (P<0.05), meanwhile which was positively correlated with 6MWT (P<0.05). Unfortunately, there was almost no correlation between the FVC, FEV1, FEV1/FVC, FEV1% pred and mMRC, 6MWT. Conclusions Compared with PFT, CPX can comprehensively reflect the status of patients with COPD.In addition to reflecting the decline of ventilatory function in COPD patients, checking CPX also can observe the ventilation efficiency, evaluate its peripheral skeletal muscle function, earlier to detect the increased pulmonary artery pressure and the potential cardiovascular dysfunction.On the whole, CPX was superior to assess patients′ dyspnea and exercise tolerance, and can reflect the prognosis of COPD patients. Key words: Chronic obstructive pulmonary disease; Cardiopulmonary exercise test; Pulmonary function test; Dyspnea score; 6 minute walking test

Objective To investigate arterial endothelial dysfunction in stable chronic obstructive pulmonary disease (COPD) patients and the correlation between the degree of endothelial dysfunction and the severity of COPD. Methods Forty stable COPD patients were enrolled in a COPD group and 30 non-COPD individuals in a control group.The endothelium-dependent flow-mediated vasodilatation (FMD) of the brachial artery and serum eNO value were measured in both groups.Forced expiratory volume in 1 second (FEV1)/prediction of FEV1 was determined and expressed as FEV1 (% pred). Results The mean FMD was significantly lower in the COPD group (11.21±5.19)% than in the control group (19.86±5.24)%(t=6.090, P=0.001). The Pearson’s correlation analysis showed FMD was positively correlated with FEV1 (%pred) in COPD patients (r=0.440, P<0.05). The mean serum eNO level in the COPD group (108.58±42.22)μmol/L was significantly lower than in the control group (151.17±97.40)μmol/L (t=2.242, P=0.039). Conclusions The endothelium-dependent flow-mediated vasodilatation is significantly impaired in stable COPD patients, and the degree of impairment is proportional to the FEV1 (% prediction of FEV1) in COPD patients. Key words: Vascular endothelium; Pulmonary disease, chronic obstructive; Nitric oxide

Left ventricular diastolic dysfunction (LVDD) is a frequent condition in chronic obstructive pulmonary disease (COPD). Tenascin-C (Tn-C) and matrix metalloproteinase-9 (MMP-9) are extracellular matrix proteins associated with myocardial fibrosis and wall remodeling because of inflammation. To determine whether the circulating levels of inflammatory markers, Tn-C and MMP-9 are associated with LVDD in COPD patients. Forty-two severe stable COPD patients (64 ± 8 years, 88% male, FEV1% 38 ± 5.7) and a control group (n = 11) were included. Pulmonary function tests and a Doppler echocardiography were performed on COPD patients. Baseline serum levels of C-reactive protein (CRP), leukocytes, fibrinogen, interleukins (IL) 6 and 8, Tn-C and MMP-9 were analyzed in all participants. COPD patients were classified in two groups: LVDD (n = 35) and non-LVDD (n = 7). Serum levels of IL-6 and CRP were higher in the LVDD group compared to the non-LVDD group [median(IQR)] [3.46 pg/mL (2.36-4.74) vs 1.87 pg/mL (1.10-3.28), P = 0.045] and [6.0 mg/L (3.0-13.0) vs 1.0 mg/L (1.0-2.3), P = 0.001], respectively. The same trend was observed in the analysis adjusted by age and BMI, being significant for CRP (P = 0.04). Circulating IL-6 was associated with the type of LVDD, being higher in the type-II (P = 0.046). Obese patients with COPD-LVDD showed a higher level of inflammatory markers (P = 0.021). Tn-C were significantly higher in patients with LVDD type-II compared to type-I [1422 ng/mL (826-1948) vs 781 ng/mL (640-1139), P = 0.015], without differences in MMP-9. Severe COPD patients with LVDD showed a different inflammatory pattern, suggesting a link between low-grade inflammation and the presence of LVDD. In COPD, high levels of Tn-C are related to LVDD type-II.

Objective: To compare clinical characteristics between patients with chronic obstructive pulmonary disease (COPD) and COPD -OSA overlap, and to analyze the risk factors for OSA in patients with COPD. Methods: A total of 431 patients with COPD were divided into a COPD-OSA group with AHI>15 events/h or a COPD group with AHI ≤ 15 events/h according to the results of polysomnography, and their clinical characteristics were summarized. Risk factors for OSA overlap in COPD patients were identified by univariate and multivariate logistic regression analyses. Results: There were no significant differences in gender composition, dyspnea scale (mMRC) score, the numbers of acute exacerbations and hospitalizations in the last year, prevalence of coronary heart disease, or cor pulmonale or diabetes mellitus in the two groups (all P>0.05). Age, BMI, neck circumference, smoking index, COPD assessment test (CAT) score, the values of FEV(1) or FEV(1)%, FEV(1)/FVC ratios, and the prevalence of hypertension in the COPD-OSA group with AHI>15 events/h were significantly higher than in the COPD group with AHI ≤15 events/h, while the duration of COPD and the proportion of severe COPD were lower than the COPD group with AHI≤ 15 (P<0.05). The scores of Charlson Comorbidity Index, Epworth Sleepiness Scale (ESS) and Sleep Apnea Clinical Score (SACS) in the COPD-OSA group were significantly higher than in the COPD group with AHI≤ 15, with all P values<0.05. Risk factors for AHI>15 OSA coinciding in patients with COPD included BMI, neck circumference, ESS, SACS and CAT (P<0.05). Furthermore, BMI, ESS and CAT were independent risk factors for OSA in COPD patients (P<0.05). Compared with mild or moderate COPD cases, patients with severe COPD (FEV(1)%<50%) had a lower risk of having OSA (β=-0.459, OR=0.632, 95% CI 0.401-0.997, P=0.048). Conclusions: Compared to COPD patients with AHI ≤ 15 events/h, OSA-COPD overlap patients (AHI>15 events/h) had a worse quality of life, more daytime sleepiness and higher prevalence of hypertension. BMI, ESS and CAT were independent risk factors for AHI>15 OSA in patients with COPD. The risk of having OSA in severe COPD patients was lower than cases with mild or moderate COPD.

Maintenance pharmacotherapy of mild and moderate COPD: What is the Evidence?

Asthma and chronic obstructive pulmonary disease (COPD) continue to have considerable impact on disease burden and mortality worldwide. Early diagnosis still remains a challenge, with low uptake of spirometry in many countries. Implementing best practice management for airways disease is a critical goal for health-care systems—the management now includes pharmacological and non-pharmacological approaches to the lung disease, as well as recognition and treatment of comorbidities. Finally, the pathogenesis of airways disease continues to be fertile field of investigation, in order to better prevent disease, slow progression and identify relevant biomarkers. A large number of studies published in Respirology in 2012 have addressed all of these important clinical and scientific issues, and made major contributions to advance this field and hopefully improve outcomes for patients with asthma and COPD. Despite years of research, the origins of asthma remain obscure. Although there is clearly a genetic disposition to developing asthma, gene-association studies have so far failed to reveal clear insights into the development of asthma (reviewed in Respirology in 20111), indicating that asthma is likely to result from a complex interaction between genes and environment. Moreover, marked changes in the prevalence of asthma in recent decades indicate that changing environmental exposures must be to blame. Air pollution is known to exacerbate asthma symptoms and has been one of the factors suspected of causing the disease in the first place. Gowers et al. reviewed the association between air pollution and asthma for the Department of Health in the United Kingdom.2 In fact, they found little evidence for an association between pollution and asthma prevalence. If anything, time trends indicated a negative rather than positive association, but there is some evidence for an increased incidence of asthma in people living very close to roads carrying heavy traffic. The overall impact of this traffic pollution on asthma incidence is not likely to be large. Air pollution of different kind was studied by Havstad et al. who studied the impact of early-life exposure to environmental tobacco smoke on the development of atopy by 2–3 years in a cohort of children.3 Using propensity score matching, they found that tobacco smoke exposure increased the risk of positive skin prick or specific immunoglobulin E (IgE) tests in children whose mothers were not atopic, but paradoxically decreased the risk in those with a positive history of maternal atopy. This interaction between maternal atopy and the effect of environmental tobacco smoke on children's risk for atopy may help to explain some of the conflicting data from previous studies. An accompanying editorial emphasizes that exposing children to tobacco smoke should of course be avoided because of the many other adverse effects,4 but the paper, like that of Gowers et al.,2 demonstrates the need to better understand how genes and environment interact to cause atopy. Other changes in lifestyle and exposures may also help to explain increases in asthma prevalence. The well-recognized association between asthma and obesity was reviewed in Respirology and the mechanism for the association continues to elude researchers.5 Changing dietary exposures could be part of the explanation. A novel association between soft drink consumption, tobacco smoking and airway disease was reported by Shi et al.6 In a large cross-sectional telephone survey of Australian adults, consumption of more than half a litre a day of soft drinks was associated with both asthma and COPD. The association was only apparent among smokers in whom soft drinks and smoking appeared to have additive effects. If these findings are confirmed in other studies, they suggest a lifestyle intervention to prevent airways disease. One of the problems in identifying the origins of asthma is that clinical asthma comprises a number of distinct phenotypes. It has recently been proposed that these phenotypes represent truly different diseases with different causes (also called ‘endotypes’) rather than simply being different and variable expressions of the same underlying pathology.7 Defining asthma phenotypes on the basis of the cellular profile of induced sputum has become increasingly important as studies indicate that eosinophilic airway inflammation responds better to corticosteroid treatment than neutrophilic inflammation.8 Phenotypes are increasingly used to target novel asthma treatments, such as the anti-interleukin (IL)-5 monoclonal antibody targeted to eosinophilic asthma.9 Specific treatments for non-eosinophilic asthma have not been established however. Choi et al. studied sputum inflammatory profiles in patients with refractory asthma requiring high-dose corticosteroid therapy selected from a large asthma cohort.10 Those with persistent airway obstruction had a longer duration of asthma and had predominantly neutrophilic inflammation, whereas refractory asthma without persistent airway obstruction was more likely to be eosinophilic. The authors suggest that this provides a rationale for developing new medications for individualized treatment in these patients. However, two studies in Respirology show that eosinophilic airway inflammation varies over time even in the absence of corticosteroid treatment. Hancox et al. found that the eosinophilic/non-eosinophilic classification was not stable over time in two clinical asthma treatment trails: even though the sputum phenotype was determined at a time when the patients were not taking any steroid treatment, nearly all patients with ‘non-eosinophilic asthma’ had raised sputum eosinophils at some point.11 Similarly, the study of Bacci et al. (discussed in the Airway Biology section) provided evidence that inflammatory phenotypes based on sputum cell analysis are not stable over time.12 Another report last year found that sputum phenotypes are not stable in children either.13 Hence, characterization of asthma and long-term treatment decisions should not be based on a single sputum specimen.14 Induced sputum analysis remains valuable for assessing patients with difficult asthma, but the resources required to obtain and analyse frequent sample will inhibit its widespread use. Although not yet established in the management of asthma, measuring of exhaled nitric oxide (eNO) offers a more practical way to monitor airway inflammation than monitoring of induced sputum.15 Affordable handheld electrochemical nitric oxide analysers are now available, making this a realistic possibility for many services. Kim et al. compared eNO measurements using the handheld Niox Mino (Aerocrine AB, Solna, Sweden) electrochemical analyser with a Sievers (GE Analytical Instruments, Boulder, CO, USA) chemiluminesence analyser.16 Correlation between the two machines was good (r = 0.88), but agreement in absolute values was only moderate: the Mino tended to give about 15% lower readings. The handheld machines are convenient but differences between machines need to be taken into account when interpreting eNO values. Although measuring airway inflammation is appealing, more simple clinical assessments remain the mainstay of asthma management. Ko et al. found that a single measurement of the Asthma Control Test—a score based on a simple 5-item questionnaire—correlated with asthma control assessments by physicians and predicted exacerbations and emergency health-care use over the following 6 months in a cohort of patients attending tertiary care in Hong Kong.17 The baseline Asthma Control Test score was better at predicting exacerbations than lung function, peak flow or eNO measurements. Simple management of asthma was also supported by a large randomized control trial comparing adjustment of inhaled steroid doses using eNO, clinical physician guidance and patient symptom-based adjustment using inhaled corticosteroids (ICS) each time they required β-agonist. No difference was found between the strategies, with the trends favouring patient symptom-led adjustment.9 Improvements in computed tomography (CT) scanning technology and lower radiation doses have enabled the use of high-resolution scans to study airway structure and differentiate between diseases, sites of inflammation and treatment response without the need for tissue biopsies.18 Kurashima et al. found that airway lumens were smaller in the 3rd- to 6th-generation bronchi in asthma but not COPD, whereas both diseases demonstrated airway wall thickening.19 These small airway diameters correlated with lung function in asthma not COPD. Hoshino and Ohtawa used high-resolution CT scans to assess changes in large airway remodelling before and after 24 weeks treatment with combination long-acting β-agonist (LABA) and ICS or ICS alone in a double-blind randomized controlled trial.20 Combination therapy reduced airway wall thickness and increased the airway luminal area to a greater extent than ICS alone. The improvements in airway wall thickness in the combination group correlated with reductions in sputum eosinophils and improvements in forced expiratory volume in 1 s (FEV1). The mechanisms for this positive interaction between ICS and LABA are not known, but the findings offer hope that airway remodelling can effectively treated and/or prevented by combination therapy. An accompanying editorial by King and Farah emphasizes the need for confirmatory and long-term studies as well as investigations of the effects on smaller airways that remain beyond the resolution of the scans.21 The findings of Hoshino and Ohtawa of a positive interaction between LABA and ICS on remodelling is relevant to the current concerns over the safety of LABA in asthma.20 Among the most controversial issues this year is the American Food and Drug Administration requirement that the manufacturers of LABA undertake large safety studies of the combination on LABA with ICS. It is accepted that using LABA without ICS is not acceptable in asthma, but it has been suggested that these large safety studies of combination therapy are futile because they will not be powered to address the question of whether they cause a small excess of asthma deaths.22 In the meantime, a recent meta-analysis demonstrates that withdrawing LABA once asthma control has been achieved, as currently recommended by the Food and Drug Administration, leads to a deterioration in control.23 Cough-variant asthma is another well-recognized but poorly understood phenotype. Ohkura et al. compared coughing during methacholine-induced bronchoconstriction in patients with cough-variant asthma (but normal cough sensitivity to capsaicin challenge) and normal controls.24 Patients with cough-variant asthma had increased cough during even mild methacholine-induced bronchoconstriction. After treatment with inhaled steroids, the number of coughs diminished to be similar to normal controls, indicating that increased cough sensitivity to bronchoconstriction is a feature of this disease variant, but that it responds to anti-inflammatory treatment. For non-asthmatic refractory chronic cough, an exciting discovery this year was that gabapentin is an effective treatment in a double-blind randomized controlled trial.25 Gabapentin is an anticonvulsant that is also used to treat neuropathic pain, suggesting that its effect on chronic cough may be due to suppression of central cough reflexes. The paradigm of Th1- versus Th2-mediated inflammation would suggest that asthma (predominantly a Th2 disease) would be less uncommon in sarcoidosis—regarded as a Th1 disorder. However, Wilsher et al. found that the prevalence of positive specific IgE tests for common aeroallergens (34%) and a history of asthma (21.5%) were similar in patients with sarcoidosis to that reported in the general population.26 In another study from the same group, Young et al. found that 44% of patients with sarcoidosis had airway hyperresponsiveness to histamine (a direct airway challenge), whereas only 11% were hyperresponsive to an indirect challenge using hypertonic saline.27 Hyperresponsiveness to histamine was more common in those with lower baseline FEV1 values and those with fibrotic and reticular patterns on lung CT. The findings suggest that the high prevalence of histamine responsiveness in patients with sarcoidosis is likely to be distinct from asthma (because of the low prevalence of hypertonic saline responsiveness) and is more likely to be due to airway remodelling caused by granulomatous airway inflammation. The development of COPD is related to both genetic and environmental factors. For genetic factors, a recent study by Guan et al. from China found that D2S388-5 microsatellite polymorphism located upstream of the surface lung surfactant protein B gene on chromosome 2 may be associated with susceptibility to COPD in Xinjiang Kazakhs.28 Another genetic factor, nucleotide-binding and oligomerization domain (NOD) 2 genes polymorphism, has also been found to have some potential association with COPD in a study from Japan. The distribution of NOD2 rs1077861 genotypes differed between COPD patients and non-COPD smokers and was associated with a lower FEV1 % predicted value in the TT when compared with the TA/AA genotypes.29 For environmental factors, exposure to noxious particles or gases is associated with the development of COPD.30 A study from Johannessen et al. found that exposure to environmental tobacco smoking during childhood was associated with COPD and respiratory symptoms in adulthood mainly in women in a cross-sectional study in Norway. In men, the most important risk factor is still acting smoking.31 The relationship of air pollution and COPD is reviewed by Ko and Hui.32 Outdoor air pollution (such as ambient air pollution) and indoor pollution (such as second-hand smoking and biomass fuel combustion exposure) are associated with the development of COPD and outdoor air pollution is a significant environmental trigger for acute exacerbation of COPD. Zeng et al. reviewed the aetiology of COPD in non-smoking subjects and risk factors may include genetic factors, long-standing asthma, outdoor air pollution, environmental smoke exposure, biomass smoke, occupational exposure, diet, recurrent respiratory infection in early childhood and tuberculosis.33 Interestingly, statins34 and even soft drink consumption6 have been found to have association with COPD. A cross-sectional study from Japan found that the prevalence of airflow limitation among patients who used statins was approximately five times lower than that among patients who did not use statins. However, statin use was not significantly associated with a lower prevalence of airflow limitation in multivariate analysis.34 Statins thus cannot be advocated for prevention of airflow obstruction at this stage. A study from South Australia assessed the relationship between soft drink consumption and presence of asthma/COPD in over 16 000 subjects.6 and noted the odds ratio for having COPD was 1.79 (95% confidence interval: 1.32–2.43) in multivariate analysis by comparing those who consumed more than half a litre of soft drink per day with those who did not consume soft drinks. The reason behind these associations is unclear and a causative relationship cannot be drawn from these studies. Comorbidities are common in COPD patients and the latest Global Initiative for Chronic Obstructive Lung Disease (GOLD) guideline has also emphasized that comorbid illness in COPD patients should be managed appropriately.30 The link between COPD and coronary artery disease is strong and complex. Coronary artery disease has a strong effect on the severity and prognosis of COPD and vice versa, including acute exacerbations.35 Ito and colleagues found that depression and sleep disorders were both common in patients with COPD.36 McSharry et al. found that sleep quality is poor in severe COPD patients with reduced sleep efficiency and reduced percentage of rapid eye movement sleep. There was a significant association between daytime hypoxaemia and sleep efficiency.37 However, depression, but not sleep disorder, is an independent risk factor for exacerbations and hospitalizations among COPD patients.36 The economic burden of COPD is huge and a recent study from Singapore showed that in 2009, COPD admissions represented 3.4% of all hospital discharges. Hospitalization was found to be the major cost driver, accounting for 73% of the total COPD burden, Between 2005 and 2009, attendances at primary care clinics, emergency departments and specialist clinics accounted for 3%, 5% and 17% of overall COPD costs, respectively.38 There are some new developments in the assessment of COPD using tools like CT and exercise tests. Degree of hyperinflation39 and airway dimensions18, 19 in COPD patients can be measured using CT parameters. Tanabe and colleagues applied a novel CT index to assess lung volume. This DLV% index measures the ratio of lung volume region adjacent to the diaphragm dome (D) to total lung volume (LV). Using this index, it was found that a reduced lung volume around the diaphragm correlated with lung hyperinflation and health-related quality of life, independent of emphysema severity.39 A recent study by Galban et al. adapted the parametric response map, a voxel-wise image analysis technique, for assessing COPD phenotype. In their study, whole-lung CT scans acquired at inspiration and expiration of COPD patients were analysed. Parametric response map identified the extent of functional small airways disease and emphysema as well as provided CT-based evidence that supports the concept that functional small airways disease precedes emphysema with increasing COPD severity.40 Phenotyping COPD by image biomarkers is currently under investigation and offers potential development of personalized therapy for COPD patients. There are also different field and laboratory tests for measuring exercise capacity in COPD patients. Hill and colleagues compared the 6-min walk test, incremental shuttle walk test and endurance shuttle walk test with a ramp cycle ergometer test in a group of patients with moderate COPD and found that these tests all elicited a similar peak rate of oxygen uptake and heart rate response. This suggested that that both self- and externally paced field tests can progress to high intensities.41 Field tests can probably offer a reasonable alternative for the evaluation of patients with moderate COPD.42 The revised was published in were indicated as the or in the treatment of all of patients with COPD. A new of and long-acting have as the most effective for control in patients with COPD. et al. reported the of one such when compared with in patients from 6 for found that provided significant and improvements in and in COPD with that reported in other from clinical indicate that may prevent acute exacerbations of However, the underlying mechanism for this effect is et al. showed that treatment in patients with COPD the and of both and by and This a effect of the in by the of and by the airway The long-term safety of this and its in to other treatment need evaluation before it a acute exacerbation of it is difficult for physicians to differentiate COPD from heart common and comorbidities. and colleagues the of for the diagnosis of in patients with severe acute exacerbations of COPD and in 2 care found that the was more in patients with normal function sensitivity and than those in and required adjustment of the to a et al. in a trial of patients with acute COPD and from heart compared treatment with versus reported more rapid in with the combination treatment but difference in This is a to the and treatment of heart during apparent COPD and sleep disorders are common and important in severe Ito et al. in a study of COPD patients and normal that only depression but not sleep disorders is associated with the increased risk of exacerbations and The management of and depression was the of a by and colleagues in they treatment with the of clinical on this important of COPD with sputum to exacerbations and poor quality of in patients with COPD. In a et al. that inhaled treatment may improve the quality of in patients with by sputum studies are to the of this is an important goal in patients with COPD.30 It quality of and the of greater and pulmonary is an effective way to in COPD long-term monitoring and of at is to the of any exercise In this et al. found that a value was correlated with severe This may be a practical of patients can and to with are and is a intervention for patients with acute exacerbations of COPD who to to treatment. It may be as the current of care in this clinical Moreover, in patients with COPD on the of and mortality from to However, there is a need to improve the practical assessment of the response to in the acute In this et al. reviewed the of for the of during acute However, they were to positive from randomized The clinical may be that of may not be a of response to and should continue to on parameters. the disease the treatment of COPD become less effective and symptoms become more for such patients need to early to complex with about values and for care including of et in a of the the approaches to care at the of in patients with severe interaction susceptibility to airway diseases such as asthma and COPD. association studies have found associations of specific single with the development of asthma or COPD. in Respirology have also on genetic of airway A meta-analysis of studies of the polymorphism in found increased risk of asthma in or with A genetic association study of COPD patients and non-COPD in Japan single in the genes and recognition that The A of single polymorphism rs1077861 in NOD2 was associated with increased risk of COPD, and NOD2 gene in with studies such as these interaction in inflammation and in the development of airway smoking is the major cause of other causes include air pollution and occupational In the development of childhood asthma, an and respiratory are The link between respiratory and Th2 has been demonstrated in asthma in with respiratory in induced airway inflammation and by and reduced to infection may also to asthma pathogenesis and as by studies of airway in In a of asthma, the as an for to by has been as a risk factor for In the Respirology on obesity and respiratory Farah and potential mechanisms for the effects of obesity in including of from tissue and changes that lung have found increased of tissue in patients with The of asthma is by Th2 IgE and cell with of the airway In non-eosinophilic asthma in some patients. In a study of patients with non-eosinophilic asthma of patients also had sputum during over 6 This was more common when they were treated with the alone without inhaled compared with This in Respirology supports the of LABA for asthma and the potential of airway inflammatory phenotype. The airway inflammation of COPD is by and A number of studies in Respirology have on other of are a of that and function more like but also link to the of were lower in the of patients with stable COPD and decreased during acute is a recognition that A study of lung tissue showed that from COPD patients and smokers had increased protein of compared with smoke exposure in increased of and increased and exposure to the smoke could inflammatory to and other of recognition in the Other have also been in COPD. of was in small airway of COPD patients and compared with in with gene of and from that had high Hence, of in the airways could to susceptibility to in the of COPD patients and Airway remodelling is an important feature of chronic In a study in airway of was increased in patients with severe asthma, compared with mild asthma or and was induced following bronchoconstriction with or has been to be for and is a potential of airway remodelling in The pathogenesis of COPD is by a response to environmental to lung that for inflammation, These have been in a number of studies in Respirology in the of may have effects in specific protein of was measured in the lung tissue of COPD with mainly in and was increased in sputum of COPD correlated with of lung function, and correlated with sputum and In another study, and tissue of were measured in from COPD patients and non-COPD of and as well as tissue of 1 and were increased in COPD, the of COPD is by acute as disease A study of patients with an exacerbation of COPD measured inflammatory biomarkers at and before of and were at the of the correlated with exacerbation severity and were reduced by the time of but not to normal of biomarkers behind clinical and could be in monitoring COPD studies into treatment in airways disease. In an asthma study, single in the region of the gene were associated with in a association study of subjects from clinical Although the function of is as yet in of by in airway increased protein of the suggesting a for in In the Respirology on into recent developments in tissue in to the The large airways have been for tissue with and or or In development of for the small airways has been more because of the and number of of the of lung will help to advance this the hope of for lung