Acute Exacerbation According to GOLD 2017 Categories in Patients with Chronic Obstructive Pulmonary Disease

IntroductionThe association between GOLD categorizations and future exacerbations has not been fully investigated. This study elucidates whether the GOLD 2017 classification is associated with different future exacerbation risk in patients with chronic obstructive pulmonary disease (COPD) compared with the previous GOLD categorization. Another objective was to investigate the impacts of the symptoms and FEV1 on the predicted future exacerbation independently of previous exacerbation history.MethodsWe analyzed patients from three prospective COPD cohorts (SNUH, KOCOSS, and KOLD) and evaluated the risk of moderate to severe exacerbation among different models, including GOLD grade (FEV1), GOLD 2011, and GOLD 2017.ResultsIn total, 611 COPD patients were included (36 from SNUH, 257 from KOCOSS, and 318 from KOLD). GOLD 2017 classification, excluding FEV1% for categorization criteria, showed no differences in future exacerbation risk compared with GOLD grade and GOLD 2011 based on c-statistics. Among those with no frequent exacerbation history and FEV1 ≥50%, the group with more symptoms was significantly associated with future exacerbations than the group with less symptoms. A lower FEV1 (FEV1 <50%) was not associated with a higher future exacerbation risk than a higher FEV1 (FEV1 ≥50%), regardless of prior exacerbation history and symptom group.ConclusionThe GOLD 2017 classification was not different from GOLD grade and GOLD 2011 regarding the association with future exacerbation risk, and there were no significant differences in exacerbation risk according to FEV1%. This suggests that FEV1 might not be an important factor in future exacerbation risk. These results partly support the GOLD 2017 assessment tool.     

Asynchrony and Hyperinflation in Patients With Chronic Obstructive Pulmonary Disease During Two Types of Upper Limbs Exercise

IntroductionOccurrence of dynamic hyperinflation during upper-limbs exercises in chronic obstructive pulmonary disease (COPD) patients is not well established. We hypothesized that dynamic hyperinflation and thoracoabdominal asynchrony occur in COPD patients accomplishing arms exercises. We assessed the occurrence and association of dynamic hyperinflation and thoracoabdominal asynchrony in COPD patients during the accomplishment of two arm exercises.Patients and methodsThis was a prospective study with 25 COPD patients. A maximal and a sub-maximal upper limbs exercise test with 50% load were performed with the diagonal technique and the arm cycle ergometer technique. Respiratory pattern, thoracoabdominal configuration and dynamic hyperinflation were assessed in the exercise tests.ResultsThirty per cent and 60% of patients hyperinflated at the end of the sub-maximum exercise tests with the diagonal and cycle ergometer techniques, respectively. Thoracoabdominal asynchrony occurred in 80% and 100% of patients who hyperinflated with the diagonal and cycle ergometer techniques, respectively. For both exercises we found enhancement of pulmonary ventilation, dyspnea, central respiratory drive and shortening of expiratory time (P<.05). Upper-limbs exercises with the diagonal technique presented less number of patients with these alterations.ConclusionsDynamic pulmonary hyperinflation and thoracoabdominal asynchrony association occurred in both upper-limbs exercises; however, the diagonal technique developed less dynamic hyperinflation and thoracoabdominal asynchrony in COPD patients than the arm cycle ergometer.     

Influence of the CYP2J2 Gene Polymorphisms on Chronic Obstructive Pulmonary Disease Risk in the Chinese Han Population

IntroductionCytochrome P450 (CYP) 2J2 is a major enzyme that controls epoxyeicosatrienoic acids biosynthesis, which may play a role in chronic obstructive pulmonary disease (COPD) development. In this study, we aimed to assess the influence of CYP2J2 polymorphisms with COPD susceptibility.Material and methodsA case–control study enrolled 313 COPD cases and 508 controls was to investigate the association between CYP2J2 polymorphisms and COPD risk. Agena MassARRAY platform was used to genotype CYP2J2 polymorphisms. Odds ratios (OR) and 95% confidence intervals (CI) were calculated to evaluate the association between CYP2J2 polymorphisms and COPD risk.ResultsWe observed rs11207535 (homozygote: OR = 0.08, 95%CI = 0.01–0.96, p = 0.047; recessive: OR = 0.08, 95%CI = 0.01–0.94, p = 0.044), rs10889159 (homozygote: OR = 0.08, 95%CI = 0.01–0.92, p = 0.043; recessive: OR = 0.08, 95%CI = 0.01–0.90, p = 0.040) and rs1155002 (heterozygote: OR = 1.63, 95%CI = 1.13–2.36, p = 0.009; dominant: OR = 1.64, 95%CI = 1.15–2.35, p = 0.006; additive: OR = 1.45, 95%CI = 1.09–1.92, p = 0.011) were significantly associated with COPD risk. Allelic tests showed T allele of rs2280274 was related to a decreased risk of COPD and T allele of rs1155002 was associated with an increased COPD risk. Stratified analyses indicated the effects of CYP2J2 polymorphisms and COPD risk were dependent on gender and smoking status (p < 0.05). Additionally, two haplotypes (A_rs11207535C_rs10889159T_rs1155002 and A_rs11207535C_rs10889159C_rs1155002) significantly decreased COPD risk.ConclusionIt suggested CYP2J2 polymorphisms were associated with COPD susceptibility in the Chinese Han population.     

Prevalence of Chronic Obstructive Pulmonary Disease in the Canary Islands

IntroductionThe prevalence of chronic obstructive pulmonary disease (COPD) varies significantly among the different geographical areas reported. In Spain, two epidemiological studies have shown a prevalence of 9–10% in the population aged over 40. However, neither of these studies included the Canary Islands, which are of interest due to their climatic conditions and high incidence of smoking.Materials and methodsA random group of 1353 subjects aged between 40 and 70 years was selected from a sample population of 596 478 individuals. Participants completed a questionnaire and then performed spirometry with bronchodilator testing if obstruction was observed. COPD was diagnosed when the post-bronchodilator FEV₁/FVC ratio was less than 0.70.ResultsThe prevalence of COPD was 7.3% (95%CI: 5.5–9.5) and was higher in males than in females (8.7% vs 6.3%, P=.134). The incidence of smoking was 29.4% (95%CI: 25.4–33.1) and was also higher in males than in females (35.1% vs 25.4%, P<.001). The prevalence of COPD stratified by severity of obstruction, according to the GOLD criteria, was 16% in group I, 69.9% in group II, 10.4% in group III and 3.3% in group IV. 71.6% of the subjects were underdiagnosed and 63.5% undertreated.ConclusionsDespite having one of the highest rates of smoking in Spain, the prevalence of COPD in the Canary Islands is lower than in most of the Spanish regions studied.     

Influence of Chronic Obstructive Pulmonary Disease on Volatile Organic Compounds in Patients with Non-Small Cell Lung Cancer

IntroductionThe etiology of lung cancer is multifactorial. Exposure to tobacco smoke and the role played by the carcinogenic compounds that it contains would explain the common association between lung cancer and chronic obstructive pulmonary disease (COPD), which is closely linked to tobacco use. In both diseases, sustained inflammation is caused by increased oxidative stress (for example, lipid peroxidation). This generates low molecular weight substances called volatile organic compounds (VOC) that are excreted during breathing. VOC metabolomics provides an indirect measure of oxidative stress.ObjectiveThe aim of this study was to establish the relative influence of COPD on the VOC profile in patients with non-small cell lung cancer (NSCLC), by first studying the possible variation of VOC associated with lung cancer histology.Patients and methodsExhaled air was tested in 107 NSCLC patients, who were divided into 2 groups: NSCLC with COPD and non-COPD with NSCLC. The exhaled air sample was obtained with the BIOVOC® sampler, and transferred to desorption tubes for later analysis by thermal desorption-gas chromatography-mass spectrometry. The VOC analysis showed lineal aldehydes and carboxylic acids.Results and conclusionsNo statistically significant differences were found in VOC associated with histology. NSCLC and COPD patients present a 1.7-fold (1.1–2.7) greater probability of detection of propionic acid (95% CI: 1.22–6.2) than patients without COPD or NSCLC (p = 0.013).     

Effects of Pulmonary Hypertension on Exercise Capacity in Patients With Chronic Obstructive Pulmonary Disease

IntroductionThe impact of pulmonary hypertension (PH) on exercise tolerance in chronic obstructive pulmonary disease (COPD) has not been fully elucidated. It is necessary to characterize pulmonary hemodynamics in patients with moderate to severe COPD in order to improve their management. The aim of the study was to determine whether in COPD the presence of PH is associated with reduced exercise tolerance in a cohort of stable COPD patients.MethodsCross-sectional analysis of 174 COPD patients clinically stable: 109 without PH and 65 with PH (COPD-PH). We assessed socio-demographic data, lung function, quality of life, dyspnea, cardiopulmonary exercise testing (CPET), constant workload endurance time (CWET), and six-minute walk test (6MWT). We elaborated a logistic regression model to explore the impact of PH on exercise capacity in COPD patients.ResultsCOPD-PH patients showed lower exercise capacity both at maximal (CPET) (43(20) versus 68(27) Watts and 50(19)% versus 71(18)% predicted peak oxygen consumption (VO₂peak), COPD-PH and COPD, respectively), and at submaximal tests (6MWT) (382(94) versus 486(95) m). In addition, the COPD-PH group had lower endurance time than the non-PH COPD group (265(113) s and 295(164) s, respectively).ConclusionsThe presence of PH is an independent factor that impairs exercise capacity in COPD.     

Classification of Chronic Obstructive Pulmonary Disease Severity According to the New Global Initiative for Chronic Obstructive Lung Disease 2011 Guidelines: COPD Assessment Test Versus Modified Medical Research Council Scale

IntroductionThe GOLD 2011 revision proposes to stratify patients with chronic obstructive pulmonary disease (COPD) by measuring the impact of the disease using the modified Medical Research Council (mMRC) scale or COPD assessment test (CAT). Our aim was to determine whether both methods are equivalent.Patients and methodsObservational study on a cohort of 283 patients diagnosed with COPD. We analyzed the demographic and lung function results. Patients were assessed by CAT and mMRC on the same day by the same interviewer, and divided into GOLD 2011 categories according to the result of the evaluation. The degree of concordance and Spearman correlation were determined. We used ANOVA on the clinical and functional variables of the four GOLD 2011 categories.ResultsOn assessing the classification of patients according to the method used, an overall correlation of ρ = 0.613 and a degree of concordance of κ = 0.63 (moderate) were obtained. κ = 0.44 was obtained for the 152 patients in categories A and B (moderate-low), and at 0.38 for the 131 patients in categories C and D (low). Differences were observed between the categories in terms of functional parameters.ConclusionsThe classification of patients with COPD using the assessment proposed by GOLD 2011 varies according to the method used (CAT or mMRC); more than 25% of patients were reclassified into different categories, implying differences in the recommended therapeutic strategy. Longitudinal studies are needed to appraise which method does better classification of the patients, according to its prognostic ability.     

Pneumonia as Comorbidity in Chronic Obstructive Pulmonary Disease (COPD). Differences Between Acute Exacerbation of COPD and Pneumonia in Patients With COPD

IntroductionPneumonia is considered an independent entity in chronic obstructive pulmonary disease (COPD), to be distinguished from an infectious exacerbation of COPD. The aim of this study was to analyze the clinical characteristics and progress of the exacerbation of COPD (ECOPD) compared to pneumonia in COPD (PCOPD) patients requiring hospitalization.Patients and methodsProspective, longitudinal, observational cohort study including 124 COPD patients requiring hospital admission for lower respiratory tract infection. Patients were categorized according to presence of ECOPD (n=104) or PCOPD (n=20), depending on presence of consolidation on X-ray. Demographic, clinical, laboratory, microbiological and progress variables were collected.ResultsPatients with ECOPD showed more severe respiratory disease according to the degree of obstruction (P<.01) and need for oxygen therapy (P<.05). PCOPD patients showed increased presence of fever (P<.05), higher blood pressure (P<.001), more laboratory abnormalities (P<.05; leukocytosis, elevated CRP, low serum albumin) and increased presence of crepitus (P<.01). Microbiological diagnosis was achieved in 30.8% of cases of ECOPD and 35% of PCOPD; sputum culture yielded the highest percentage of positive results, predominantly Pseudomonas aeruginosa. Regarding the progress of the episode, no differences were found in hospital stay, need for ICU or mechanical ventilation.ConclusionsOur data confirm clinical and analytical differences between ECOPD and PCOPD in patients who require hospital admission, while there were no differences in subsequent progress.     

The Role of Vitamin D in Chronic Obstructive Pulmonary Disease,Asthma and Other Respiratory Diseases

There has been a growing interest in recent years in the extraosseous effects of vitamin D.In this article, we review the physiology of vitamin D, the physiopathological effects associated with vitamin D deficit and the available evidence on its etiopathogenic role in respiratory diseases. Given the pleiotropic actions of vitamin D, it is biologically plausible that the deficit of this vitamin could play a pathogenic role in the development of various respiratory diseases. However, the many epidemiological studies that have shown an association between low vitamin D levels and a higher risk of developing various respiratory diseases, or a poorer prognosis if they do appear, were unable to show causality. Post hoc analyses of some clinical trials, particularly in chronic obstructive pulmonary disease (COPD) and asthma, appear to suggest that some patient subtypes may benefit from correction of a vitamin D deficit. In this respect, it would be interesting to determine if the interindividual differences found in the effect of vitamin D deficit and responses to correcting this deficit could be explained by the genetic variants involved in vitamin D metabolism. Ultimately, only appropriately designed clinical trials will determine whether 25-OH D supplements can prevent or improve the course of the various respiratory diseases in which an epidemiological association between prognosis and vitamin D deficit has been described.     

Distribution of Clinical Phenotypes in Patients With Chronic Obstructive Pulmonary Disease Caused by Biomass and Tobacco Smoke

IntroductionExposure to biomass smoke is a risk factor for chronic obstructive pulmonary disease (COPD). It is unknown whether COPD caused by biomass smoke has different characteristics to COPD caused by tobacco smoke.ObjectiveTo determine clinical differences between these two types of the disease.MethodsRetrospective observational study of 499 patients with a diagnosis of COPD due to biomass or tobacco smoke. The clinical variables of both groups were compared.ResultsThere were 122 subjects (24.4%) in the biomass smoke group and 377 (75.5%) in the tobacco smoke group. In the tobacco group, the percentage of males was higher (91.2% vs 41.8%, P<.0001) and the age was lower (70.6 vs 76.2 years, P<.0001). Body mass index and FEV₁% values were higher in the biomass group (29.4±5.7 vs 28.0±5.1, P=.01, and 55.6±15.6 vs 47.1±17.1, P<.0001, respectively). The mixed COPD-asthma phenotype was more common in the biomass group (21.3% vs 5%, P<.0001), although this difference disappeared when corrected for gender. The emphysema phenotype was more common in the tobacco group (45.9% vs 31.9%, P=.009). The prevalence of chronic bronchitis, exacerbator phenotypes, the comorbidity burden and the rate of hospital admissions were the same in both groups.ConclusionDifferences were observed between COPD caused by biomass and COPD caused by tobacco smoke, although these may be attributed in part to uneven gender distribution between the groups.     

A Population-Based Cohort Study on Chronic Obstructive Pulmonary Disease in Latin America: Methods and Preliminary Results. The PLATINO Study Phase II

BackgroundThe PLATINO baseline study, conducted from 2003 to 2005 in five Latin American cities (São Paulo, Mexico City, Montevideo, Santiago, Caracas), showed a high prevalence of chronic obstructive pulmonary disease (COPD).Methods/designA follow-up study was conducted in three out of the five centers (Montevideo, Santiago, and São Paulo) after a period of 5, 6 and 9 years, respectively, aimed at verifying the stability of the COPD diagnosis over time, the evolution of the disease in terms of survival, morbidity and respiratory function, and the analyses of inflammatory and genetic biomarkers in the blood. Some questions were added to the original questionnaire and death certificates were obtained from the national official registries.ResultsThe fieldwork has been concluded in the three centers. From the original samples in the PLATINO study phase i, we were able to locate and interview 85.6% of patients in Montevideo, 84.7% in Santiago and 77.7% in São Paulo. Individuals who could not be located had higher education levels in Brazil, and were more likely to be current smokers in Santiago and São Paulo than in Montevideo. The overall quality of spirometries was ≥80% according to American Thoracic Society criteria. The number of deaths was 71 (Montevideo), 95 (Santiago) and 135 (São Paulo), with death certificates obtained from the national mortality registries for 76.1%, 88.3% and 91.8% of cases in Montevideo, Santiago and São Paulo, respectively.ConclusionsThis study shows that it is possible to perform population-based longitudinal studies in Latin American with high follow-up rates and high-quality spirometry data. The adequacy of national mortality registries varies among centers in Latin America.     

Prevalence of Anaemia Associated With Chronic Obstructive Pulmonary Disease. Study of Associated Variables

BackgroundAnaemia is one of the extrapulmonary manifestations of chronic obstructive pulmonary disease (COPD). Its real prevalence, physiopathology and clinical repercussion are unknown. The objectives of our study were: to determine the prevalence of anaemia in patients with stable COPD not attributable to other causes and to establish the relationship of anaemia with clinical, prognostic and inflammatory markers with an important role in COPD.MethodsThe study included stable COPD patients with no other known causes of anaemia. The following tests were carried out: respiratory function tests; serum determination of erythropoietin and inflammatory markers: high sensitivity C-reactive protein (hs-CRP), fibrinogen, interleukin 6 (IL-6), interleukin 8 (IL-8) and tumour necrosis factor α (TNF-α). Body mass index (BMI), Charlson and BODE indices, the number of exacerbations in the previous year, dyspnoea and quality of life were also calculated.ResultsOne hundred and thirty patients were included. Anaemia prevalence was 6.2%. Mean haemoglobin value in anaemic patients was 11.9 ± 0.95 g/dL. Patients with anaemia had a lower BMI (P=.03), higher Charlson index (P=.002), more elevated erythropoietin levels (P=.016), a tendency to present a lower FEV₁% value (P=.08) and significantly lower IL-6 values when compared to non-anaemic patients (P=.003).ConclusionsIn our series, the anaemia associated with COPD was less prevalent than that published in the literature to date, and was related to certain clinical and inflammatory markers.     

Telerehabilitation Programme as a Maintenance Strategy for COPD Patients: A 12-Month Randomized Clinical Trial

BackgroundThere is uncertainty regarding efficacy of telehealth-based approaches in COPD patients for sustaining benefits achieved with intensive pulmonary rehabilitation (PR).Research questionTo determine whether a maintenance pulmonary telerehabilitation (TelePR) programme, after intensive initial PR, is superior to usual care in sustaining over time benefits achieved by intensive PR.Study design and methodsA multicentre open-label pragmatic parallel-group randomized clinical trial was conducted. Two groups were created at completion of an 8-week intensive outpatient hospital PR programme. Intervention group (IG) patients were given appropriate training equipment and instructed to perform three weekly training sessions and send performance data through an app to a web-based platform. Patients in the control group (CG) were advised to exercise regularly (usual care).ResultsNinety-four patients (46 IG, 48 CG) were randomized. The analysis of covariance showed non-significant improvements in 6-min walk distance [19.9 m (95% CI ∧4.1/+43.8)] and Chronic Respiratory Disease Questionnaire ? Emotion score [0.4 points (0?0.8)] in the IG. Secondary linear mixed models showed improvements in the IG in Short Form-36 mental component summary [9.7, (4.0?15.4)] and Chronic Respiratory Disease Questionnaire ? Emotion [0.5, (0.2?0.9)] scores, but there was no association between compliance and outcomes. Acute exacerbations were associated with a marginally significant decrease in 6-minute walk distance of 15.8 m (∧32.3/0.8) in linear models.ConclusionsThe TelePR maintenance strategy was both feasible and safe but failed to show superiority over usual care, despite improvements in some HRQoL domains. Acute exacerbations may have an important negative influence on long-term physical function.ClinicalTrials.gov identifierNCT03247933.     

Comparison of Intermittent Positive Pressure Breathing and Temporary Positive Expiratory Pressure in Patients With Severe Chronic Obstructive Pulmonary Disease

BackgroundResults supporting the use and the effectiveness of positive expiratory, pressure devices in chronic obstructive pulmonary disease (COPD) patients are still controversial. We have tested the hypothesis that adding TPEP or IPPB to standard pharmacological therapy may provide additional clinical benefit over, pharmacological therapy only in patients with severe COPD.MethodsForty-five patients were randomised in three groups: a group was treated with IPPB, a group was treated with TPEP and a group with pharmacological therapy alone (control group).Primary outcome measures included the measurement of scale, or questionnaire concerning dyspnoea (MRC scale); dyspnoea, cough, and sputum (BCSS) and quality of life (COPD assessment test) (CAT). Secondary outcome measures were respiratory function testing, arterial blood gas analysis and haematological examinations.ResultsPatients in both the IPPB group and the TPEP group showed a significant improvement in two of three tests (MRC, CAT) compared to the control group. However, in the group comparison analysis for the same variables between the IPPB group and the TPEP group, we observed a significant improvement in the IPPB group (P≤.05 for MRC and P≤.01 for CAT).The difference of action of the two techniques is evident in the results of pulmonary function testing: IPPB increases FVC, FEV1, and MIP; this reflects its capacity to increase lung volume. Also TPEP increases FVC and FEV1 (less than IPPB), and MEP, while decreasing total lung capacity and residual volume.ConclusionsThe two techniques (IPPB and TPEP) improve significantly dyspnoea, quality of life tools and lung function in patients with severe COPD. IPPB demonstrated a greater effectiveness in improving dyspnoea and quality of life tools (MRC, CAT) than TPEP.     

Accuracy of a New Algorithm to Identify Asthma–COPD Overlap (ACO) Patients in a Cohort of Patients with Chronic Obstructive Airway Disease

Objectives

We aimed to characterize the clinical, functional and inflammatory features of patients diagnosed diagnosed with ACO according to a new algorithm and to compare them with those of other chronic obstructive airway disease (COAD) categories (asthma and COPD).

Pulmonary rehabilitation

Pulmonary rehabilitation (PR) has been shown to improve dyspnea, exercise capacity and health-related quality of life in patients with chronic obstructive pulmonary disease (COPD). PR has also shown benefits in diseases other than COPD but the level of evidence is lower. The fundamental components of PR programs are muscle training, education and chest physiotherapy. Occupational therapy, psychosocial support and nutritional intervention should also be considered. Home programs have been shown to be as effective as hospital therapy. The duration of rehabilitation programs should not be less than 8 weeks or 20 sessions. Early initiation of PR, even during exacerbations, has proven safe and effective. The use of oxygen or noninvasive ventilation during training is controversial and dependent on the patient's situation. At present, the best strategy for maintaining the benefits of PR in the long term is unknown. Longer PR programs or telemedicine could play a key role in extending the results obtained.     

Incorporating new evidence on inhaled medications in COPD. The latin American chest association (ALAT) 2019

This document on COPD from the Latin American Chest Association (ALAT-2019) uses PICO methodology to analyze new evidence on inhaled medication and answer clinical questions. The following key points emerged from this analysis: 1) evidence is lacking on the comparison of short-acting vs. long-acting bronchodilators in patients with mild COPD; patients with moderate-to-severe COPD obtain greater benefit from long-acting bronchodilators; 2) the benefits of monotherapy with long-acting antimuscarinic agents (LAMA) and combined therapy with long-acting β₂-agonists and inhaled corticosteroids (LABA/ICS) are similar, although the latter is associated with a greater risk of pneumonia; 3) LABA/LAMA offer greater benefits in terms of lung function and risk of exacerbation than LABA/ICS (the latter involve an increased risk of pneumonia), 4) LAMA/LABA/ICS have greater therapeutic benefits than LABA/LAMA on the risk of moderate-severe exacerbations. With regard to the role of eosinophils in guiding the use of ICS, ICS withdrawal must be considered when the initial indication was wrong or no response is elicited, in patients with side effects such as pneumonia, and in patients with a low risk of exacerbation and an eosinophil blood count of < 300 cells/μl. All this evidence, categorized according to the severity of the obstruction, symptoms, and risk of exacerbations, has been used to generate an algorithm for the use of inhaled medication in COPD.     

Hypermethylation of Anti-oncogenic MicroRNA 7 is Increased in Emphysema Patients

IntroductionMicroRNA-7 (miR-7) has a suppressive role in lung cancer and alterations in its DNA methylation may contribute to tumorigenesis. As COPD patients with emphysema have a higher risk of lung cancer than other COPD phenotypes, we compared the miR-7 methylation status among smoker subjects and patients with various COPD phenotypes to identify its main determinants.Methods30 smoker subjects without airflow limitation and 136 COPD patients without evidence of cancer were recruited in a prospective study. Clinical and functional characteristics were assessed and patients were classified into: frequent exacerbator, emphysema, chronic bronchitis and asthma COPD overlap (ACO). DNA collected from buccal epithelial samples was isolated and bisulfite modified. miR-7 methylation status was evaluated by quantitative methylation-specific polymerase chain reaction (qMSP).ResultsmiR-7 Methylated levels were higher in COPD patients than in smokers without airflow limitation (23.7 ± 12.4 vs. 18.5 ± 8.8%, p = 0.018). Among COPD patients, those with emphysema had higher values of methylated miR-7 (27.1 ± 10.2%) than those with exacerbator (19.4 ± 9.9%, p = 0.004), chronic bronchitis (17.3 ± 9.0%, p = 0.002) or ACO phenotypes (16.0 ± 7.2%, p = 0.010). After adjusting for clinical parameters, differences between emphysematous patients and those with other phenotypes were retained. In COPD patients, advanced age, mild-moderate airflow limitation, reduced diffusing capacity and increased functional residual capacity were identified as independent predictors of methylated miR-7 levels.ConclusionThe increase of miR-7 methylation levels experienced by COPD patients occurs mainly at the expense of the emphysema phenotype, which might contribute to explain the higher incidence of lung cancer in these patients.