Clinical Phenotypes of COPD: Identification, Definition and Implications for Guidelines

Characteristics and phenotypes of a COPD cohort from referral hospital clinics in Uganda

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a heterogeneous condition with varied clinical and pathophysiological characteristics. Although there is increasing evidence that COPD in low-income and middle-income countries may have different clinical characteristics from that in high-income countries, little is known about COPD phenotypes in these settings. We describe the clinical characteristics and risk factor profile of a COPD population in Uganda.

METHODS

We cross sectionally analysed the baseline clinical characteristics of 323 patients with COPD aged 30 years and above who were attending 2 national referral outpatient facilities in Kampala, Uganda between July 2019 and March 2021. Logistic regression was used to determine factors associated with spirometric disease severity.

RESULTS

The median age was 62 years; 51.1% females; 93.5% scored COPD Assessment Test >10; 63.8% modified medical research council (mMRC) >2; 71.8% had wheezing; 16.7% HIV positive; 20.4% had a history of pulmonary tuberculosis (TB); 50% with blood eosinophilic count >3%, 51.7% had 3 or more exacerbations in the past year. Greater severity by Global initiative for Chronic Obstructive Lung Disease (GOLD) stage was inversely related to age (aOR=0.95, 95% CI 0.92 to 0.97), and obesity compared with underweight (aOR=0.25, 95% CI 0.07 to 0.82). Regarding clinical factors, more severe airflow obstruction was associated with SPO2 <93% (aOR=3.79, 95% CI 2.05 to 7.00), mMRC ≥2 (aOR=2.21, 95% CI 1.08 to 4.53), and a history of severe exacerbations (aOR=2.64, 95% CI 1.32 to 5.26).

CONCLUSION

Patients with COPD in this population had specific characteristics and risk factor profiles including HIV and TB meriting tailored preventative approaches. Further studies are needed to better understand the pathophysiological mechanisms at play and the therapeutic implications of these findings.

A model-based approach to generating annotated pressure support waveforms

Large numbers of asynchronies during pressure support ventilation cause discomfort and higher work of breathing in the patient, and are associated with an increased mortality. There is a need for real-time decision support to detect asynchronies and assist the clinician towards lung-protective ventilation. Machine learning techniques have been proposed to detect asynchronies, but they require large datasets with sufficient data diversity, sample size, and quality for training purposes. In this work, we propose a method for generating a large, realistic and labeled, synthetic dataset for training and validating machine learning algorithms to detect a wide variety of asynchrony types. We take a model-based approach in which we adapt a non-linear lung-airway model for use in a diverse patient group and add a first-order ventilator model to generate labeled pressure, flow, and volume waveforms of pressure support ventilation. The model was able to reproduce basic measured lung mechanics parameters. Experienced clinicians were not able to differentiate between the simulated waveforms and clinical data (P = 0.44 by Fisher's exact test). The detection performance of the machine learning trained on clinical data gave an overall comparable true positive rate on clinical data and on simulated data (an overall true positive rate of 94.3% and positive predictive value of 93.5% on simulated data and a true positive rate of 98% and positive predictive value of 98% on clinical data). Our findings demonstrate that it is possible to generate labeled pressure and flow waveforms with different types of asynchronies.

One-Year Evolution of Symptoms and Health Status of the COPD Multi-Dimensional Phenotypes: Results from the Follow-Up of the STORICO Observational Study

Aim

Describing the 1-year evolution of symptoms and health status in COPD patients enrolled in the STORICO study (observational study on characterization of 24-h symptoms in patients with COPD) classified in multidimensional phenotypes (m-phenotypes).

Methods

In our previous study, we performed an exploratory factor analysis to identify clinical and pathophysiological variables having the greatest classificatory properties, followed by a cluster analysis to group patients into m-phenotypes (mild COPD (MC), mild emphysematous (ME), severe bronchitic (SB), severe emphysematous (SE), and severe mixed COPD (SMC)). COPD symptoms were recorded at baseline, 6-, and 12-month follow-up and their evolution was described as frequency of patients with always present, always absent, arising’, ‘no more present symptoms. QoL and quality of sleep were evaluated using the SGRQ and CASIS questionnaires, respectively.

Results

We analyzed 379 subjects (144 MC, 71 ME, 96 SB, 14 SE, 54 SMC). M-phenotypes were stable over time in terms of presence of symptoms and health status with selected differences in evolution of symptoms in mild vs severe m-phenotypes. Indeed, 28.1% SB, 50.0% SE and 24.1% SMC vs 0.7% MC and 5.6% ME with night-time symptoms at baseline had no more symptoms at 6-month (p-value night-time symptom evolution MC vs SB, SE, SMC and ME vs SB, SE, SMC <0.0001). All m-phenotypes improved in quality of sleep, more markedly the severe than the mild ones (p-values CASIS score change between baseline and 6- or 12-month in MC, ME vs SB, SE, SMC <0.0001). QoL did not change during observation, irrespectively of m-phenotype.

Conclusion

Over 1 year, severe m-phenotypes showed an improvement in night-time symptoms and quality of sleep, but not QoL. Being stable over time, m-phenotypes seem worthy of testing for classificatory and prognostic purposes.

Withdrawal of Inhaled Corticosteroids in Patients with COPD - A Prospective Observational Study

Background

Inhaled corticosteroids (ICS) are widely used in the treatment of chronic obstructive pulmonary disease (COPD), but recent studies have raised doubts whether all COPD patients will benefit from ICS. This study evaluates in a real-life setting the effects of ICS withdrawal in patients with COPD.

Methods

The study was a prospective intervention study following patients with COPD for 6 months after abrupt withdrawal of ICS. FEV1 (L), blood eosinophilic count (x10E9/L) and number of exacerbations were measured at baseline, 1, 3 and 6 months after ICS withdrawal.

Results

Ninety-six patients (56 females (57.4%), mean age 70 years (51-94 years)) with COPD were included in the study. Eleven patients were excluded during the study period (7 patients died, 4 patients withdrew their consent during the study period). During the 6 months, 51 patients (60%) had resumed treatment with ICS, of whom 34 patients (68%) experienced an exacerbation during follow-up. No significant decline in FEV1 was seen in this group between baseline and after 6 months (ΔFEV1 0.07 L, p = 0.09). In the remaining 34 patients (40%) without ICS after 6 months of follow-up, 15 patients (44.1%) experienced an exacerbation. No significant decline was seen in FEV1 at baseline and after 6 months (ΔFEV1 0.04 L, p = 0.28). There were no statistically significant differences between the two groups in age (70.5 vs 69.6 years, p = 0.53), nor between FEV1 at baseline (0.96 L vs 1.00 L, p = 0.63) or eosinophilic count (0.25 x10E9/L vs 0.17 x10E9/L, p = 0.07).

Conclusion

Abrupt withdrawal of ICS was possible in some patients. However, more than half of the patients resumed ICS during follow-up. Based on results from our study we were not able to foresee - from neither history of exacerbations nor eosinophilic count - whom will be able to manage without ICS and who will resume treatment with ICS.

Clinical heterogeneity of a population of patients admitted to the Emergency Department with a diagnosis of COPD-exacerbation: Relevance of cardiovascular comorbidities

FEV1-based Chronic Obstructive Pulmonary Disease (COPD) severity does not account for the complexity of the disease. Recent studies point to the high frequency of comorbidities responsible for unfavorable outcomes. There is a lack of data on this concerning the patient evaluated in the emergency setting. Aim of the study was to prospectively evaluate patients admitted to the ED for “exacerbated COPD” to describe their clinical heterogeneity and the influence that it may have on outcomes: death, length of hospitalization, exacerbation recurrence. The following data were recorded: history, symptoms, blood gas analysis, laboratory and radiological findings and comorbidities. Each patient underwent electrocardiography, echocardiography and spirometry. In order to identify a correlation between these variables and the selected outcomes, a multivariate linear logistic regression analysis was carried out. This study was conducted on 41 eligible patients consecutively admitted to the emergency room for exacerbated COPD. A consistent proportion showed ECG, Echocardiographic and laboratory abnormalities. At spirometry a FEV1 <30% of predicted was detected in 37% of patients. Cardiovascular comorbidities came out to be very frequent (hypertension, heart failure and coronary artery disease in particular). The history of heart failure was related to the risk of re-hospitalization within three months, while pneumonia, a low pH and a low FEV1 predicted a hospital stay >7 days. Our study shows that the term “exacerbated COPD” underscores a heterogeneous population, with a high prevalence of cardiovascular comorbidities, which significantly influence outcomes. Multicenter studies are needed to better investigate the clinical relevance of these findings.

Prevalence and clinical features of most frequent phenotypes in the Italian COPD population: the CLIMA Study

Background

Chronic obstructive pulmonary disease (COPD) is a complex, progressive respiratory condition characterized by heterogeneous clinical presentations (phenotypes). The aim of this study was to assess the prevalence of the main COPD phenotypes and match of each phenotype to the most fitting clinical and lung function profile.

Methods

the CLIMA (Clinical Phenotypes in Actual Clinical Practice) study was an observational, cross-sectional investigation involving twenty-four sites evenly distributed throughout Italy. Patients were tentatively grouped based on their history and claimed prevailing symptoms at recruitment: chronic cough (CB, suggesting chronic bronchitis); dyspnoea (possible emphysema components, E); recurrent wheezing (presuming asthma components, A). Variables collected were: anagraphics; smoking habit; history of asthma; claim of >1 exacerbations in the previous year; blood eosinophil count; total blood IgE and alpha¹ anti-trypsin (α¹-AT) levels; complete lung function, and the chest X-ray report. mMRC, CAT, BCS, EQ5d-5L were also used. The association between variables and phenotypes were checked by Chi-square test and multinomial logistic regression.

Results

The CB phenotype was prevalent (48.3%), followed by the E and the A phenotypes (38.8% and 12.8%, respectively). When dyspnoea was the prevailing symptom, the probability of belonging to the COPD-E phenotype was 3.40 times higher. Recurrent wheezing was mostly related to the COPD-A phenotype. Lung function proved more preserved in the COPD-CB phenotype. Smoke; n. exacerbations/year; VR, and BODE index were positively correlated with the COPD-E phenotype, while SpO₂, FEV₁/FVC, FEV₁/VC, and FEV₁ reversibility were negatively correlated. Lower DLco values were highly probative for the COPD-E phenotype (p<0.001). Conversely, smoke, wheezing, plasma eosinophils, FEV₁ reversibility, and DLco were positively correlated with the COPD-A phenotype. The probability of belonging to the COPD-A phenotype raised by 2.71 times for any increase of one unit in % plasma eosinophils (p<0.001). Also multiparametrical scores contributed to discriminate the three phenotypes.

Conclusion

The recognition of the main phenotypes of COPD can be effectively pursued by means of a few clinical and instrumental parameters, easy to obtain also in current daily practice. The phenotypical approach is crucial in the management of COPD as it allows to individualize the therapeutic strategy and to obtain more effective clinical outcomes.

Chronic obstructive pulmonary disease - diagnosis and management of stable disease; a personalized approach to care, using the treatable traits concept based on clinical phenotypes. Position paper of the Czech Pneumological and Phthisiological Society

This position paper has been drafted by experts from the Czech national board of diseases with bronchial obstruction, of the Czech Pneumological and Phthisiological Society. The statements and recommendations are based on both the results of randomized controlled trials and data from cross-sectional and prospective real-life studies to ensure they are as close as possible to the context of daily clinical practice and the current health care system of the Czech Republic. Chronic Obstructive Pulmonary Disease (COPD) is a preventable and treatable heterogeneous syndrome with a number of pulmonary and extrapulmonary clinical features and concomitant chronic diseases. The disease is associated with significant mortality, morbidity and reduced quality of life. The main characteristics include persistent respiratory symptoms and only partially reversible airflow obstruction developing due to an abnormal inflammatory response of the lungs to noxious particles and gases. Oxidative stress, protease-antiprotease imbalance and increased numbers of pro-inflammatory cells (mainly neutrophils) are the main drivers of primarily non-infectious inflammation in COPD. Besides smoking, household air pollution, occupational exposure, low birth weight, frequent respiratory infections during childhood and also genetic factors are important risk factors of COPD development. Progressive airflow limitation and airway remodelling leads to air trapping, static and dynamic hyperinflation, gas exchange abnormalities and decreased exercise capacity. Various features of the disease are expressed unequally in individual patients, resulting in various types of disease presentation, emerging as the "clinical phenotypes" (for specific clinical characteristics) and "treatable traits" (for treatable characteristics) concept. The estimated prevalence of COPD in Czechia is around 6.7% with 3,200-3,500 deaths reported annually. The elementary requirements for diagnosis of COPD are spirometric confirmation of post-bronchodilator airflow obstruction (post-BD FEV₁/VCmax <70%) and respiratory symptoms assessement (dyspnoea, exercise limitation, cough and/or sputum production. In order to establish definite COPD diagnosis, a five-step evaluation should be performed, including: 1/ inhalation risk assessment, 2/ symptoms evaluation, 3/ lung function tests, 4/ laboratory tests and 5/ imaging. At the same time, all alternative diagnoses should be excluded. For disease classification, this position paper uses both GOLD stages (1 to 4), GOLD groups (A to D) and evaluation of clinical phenotype(s). Prognosis assessment should be done in each patient. For this purpose, we recommend the use of the BODE or the CADOT index. Six elementary clinical phenotypes are recognized, including chronic bronchitis, frequent exacerbator, emphysematous, asthma/COPD overlap (ACO), bronchiectases with COPD overlap (BCO) and pulmonary cachexia. In our concept, all of these clinical phenotypes are also considered independent treatable traits. For each treatable trait, specific pharmacological and non-pharmacological therapies are defined in this document. The coincidence of two or more clinical phenotypes (i.e., treatable traits) may occur in a single individual, giving the opportunity of fully individualized, phenotype-specific treatment. Treatment of COPD should reflect the complexity and heterogeneity of the disease and be tailored to individual patients. Major goals of COPD treatment are symptom reduction and decreased exacerbation risk. Treatment strategy is divided into five strata: risk elimination, basic treatment, phenotype-specific treatment, treatment of respiratory failure and palliative care, and treatment of comorbidities. Risk elimination includes interventions against tobacco smoking and environmental/occupational exposures. Basic treatment is based on bronchodilator therapy, pulmonary rehabilitation, vaccination, care for appropriate nutrition, inhalation training, education and psychosocial support. Adequate phenotype-specific treatment varies phenotype by phenotype, including more than ten different pharmacological and non-pharmacological strategies. If more than one clinical phenotype is present, treatment strategy should follow the expression of each phenotypic label separately. In such patients, multicomponental therapeutic regimens are needed, resulting in fully individualized care. In the future, stronger measures against smoking, improvements in occupational and environmental health, early diagnosis strategies, as well as biomarker identification for patients responsive to specific treatments are warranted. New classes of treatment (inhaled PDE3/4 inhibitors, single molecule dual bronchodilators, anti-inflammatory drugs, gene editing molecules or new bronchoscopic procedures) are expected to enter the clinical practice in a very few years.

New opportunities of dual bronchodilation therapy for patients with chronic obstructive pulmonary disease

Currently, combinations of long-acting beta2-agonists and long-acting anticholinergics are considered as the basic therapy for majority of patients with chronic obstructive pulmonary disease (COPD). These combinations have different pharmacological characteristics and delivery devices that provides different clinical effects and new opportunities for personalized treatment of COPD. Aclidinium/formoterol fixed combination differs from other dual bronchodilators by twice-daily dosing regimen, good safety profile and a specific delivery system. Recent information on clinical efficacy and safety of aclidinium/formoterol combination in COPD patients is given in this article.

Endobronchial biopsy in the final diagnosis of chronic obstructive pulmonary disease and asthma: a clinicopathological study

BACKGROUND

Asthma and chronic obstructive pulmonary disease (COPD) are chronic conditions with an increasing prevalence in developing countries. The evaluation of endobronchial biopsies has emerged as a tool to differentiate between both conditions via the measurement of the reticular basement membrane (RBM) thickness with various conclusions drawn from different studies.

OBJECTIVES

Compare the thickness of the RBM between asthma and COPD and evaluate other histomorphological features in both groups.

DESIGN

Prospective, descriptive and analytical.

SETTING

University teaching hospital.

PATIENTS AND METHODS

The study included patients with COPD and irreversible and reversible asthma with diagnosis based on clinical assessment, pulmonary function tests and high-resolution computed tomography scans. Endobronchial biopsies were obtained from all patients and, using a light microscope and a computerized image analyzer, the thickness of the reticular basement membrane was calculated in all patients. We also made a qualitative assessment of other histo-morphological features.

MAIN OUTCOME MEASURES

Mean RBM thickness.

SAMPLE SIZE

Thirty male patients.

RESULTS

The mean RBM thickness in asthmatic patients was 8.9 (2.4) micro m. The mean RBM thickness in COPD patients was 5.3 (1.1) micro m. However, there was no thickening of the RBM in patients with reversible asthma. The RBM was significantly thicker in patients with irreversible asthma than in patients with COPD or reversible asthma. There were no significant differences in epithelial desquamation or metaplasia, mucosal or submucosal inflammation, the presence of eosinophils, submucosal glandular hyperplasia or submucosal smooth muscle hyperplasia between groups.

CONCLUSIONS

The thickness of the RBM is the only reproducible histopathological feature to differentiate COPD from irreversible asthma.

LIMITATIONS

The study included a limited number of patients. A qualitative approach was used to compare epithelial cell injury, inflammation, submucosal glandular and muscular hyperplasia.

CONFLICT OF INTEREST

None.

Using Big Data to Assess Prescribing Patterns in Greece: The Case of Chronic Obstructive Pulmonary Disease

INTRODUCTION

Chronic Obstructive Pulmonary Disease (COPD) is one of the top leading causes of death and disability, and its management is focused on reducing risk factors, relieving symptoms, and preventing exacerbations. The study aim was to describe COPD prescribing patterns in Greece by using existing health administrative data for outpatients.

METHODS

This is a retrospective cross-sectional study based on prescriptions collected by the largest social insurance fund, during the first and last trimester of 2012. Selection criteria were the prescription of specific active substances and a COPD diagnosis. Extracted information included active substance, strength, pharmaceutical form and number of packages prescribed, diagnosis, time of dispensing, as well as insurees' age, gender, percentage of co-payment and social security unique number. Statistical analysis included descriptive statistics and logistic regression.

RESULTS

174,357 patients received medicines for COPD during the study period. Patients were almost equally distributed between male and female, and age above 55 years was strongly correlated with COPD. Most patients received a long-acting beta agonist plus inhaled corticosteroid combination (LABA +ICS), followed by long-acting muscarinic agonist (LAMA). 63% patients belonging in the 35-54 age received LABA+ICS. LAMA was prescribed more frequently among males and was strongly correlated with COPD.

CONCLUSION

The study provides big data analysis of Greek COPD prescribing patterns. It highlights the need for appropriate COPD classification in primary care illustrating the role of electronic prescribing in ensuring appropriate prescribing. Moreover, it indicates possible gender differences in treatment response or disease severity, and the impact of statutory co-payments on prescribing.

Epigenetic mechanisms in respiratory muscle dysfunction of patients with chronic obstructive pulmonary disease

Epigenetic events are differentially expressed in the lungs and airways of patients with chronic obstructive pulmonary disease (COPD). Moreover, epigenetic mechanisms are involved in the skeletal (peripheral) muscle dysfunction of COPD patients. Whether epigenetic events may also regulate respiratory muscle dysfunction in COPD remains unknown. We hypothesized that epigenetic mechanisms would be differentially expressed in the main inspiratory muscle (diaphragm) of patients with COPD of a wide range of disease severity compared to healthy controls. In diaphragm muscle specimens (thoracotomy due to lung localized neoplasms) of sedentary patients with mild-to-moderate and severe COPD, with preserved body composition, and sedentary healthy controls, expression of muscle-enriched microRNAs, histone acetyltransferases (HATs) and deacetylases (HDACs), total DNA methylation and protein acetylation, small ubiquitin-related modifier (SUMO) ligases, muscle-specific transcription factors, and muscle structure were explored. All subjects were also clinically evaluated: lung and muscle functions and exercise capacity. Compared to healthy controls, patients exhibited moderate airflow limitation and diffusion capacity, and reduced exercise tolerance and transdiaphragmatic strength. Moreover, in the diaphragm of the COPD patients, muscle-specific microRNA expression was downregulated, while HDAC4 and myocyte enhancer factor (MEF)2C protein levels were higher, and DNA methylation levels, muscle fiber types and sizes did not differ between patients and controls. In the main respiratory muscle of COPD patients with a wide range of disease severity and normal body composition, muscle-specific microRNAs were downregulated, while HDAC4 and MEF2C levels were upregulated. It is likely that these epigenetic events act as biological adaptive mechanisms to better overcome the continuous inspiratory loads of the respiratory system in COPD. These findings may offer novel therapeutic strategies to specifically target respiratory muscle dysfunction in patients with COPD.

Do epigenetic events take place in the vastus lateralis of patients with mild chronic obstructive pulmonary disease?

Muscle dysfunction is a major comorbidity in Chronic Obstructive Pulmonary Disease (COPD). Several biological mechanisms including epigenetic events regulate muscle mass and function in models of muscle atrophy. Investigations conducted so far have focused on the elucidation of biological mechanisms involved in muscle dysfunction in advanced COPD. We assessed whether the epigenetic profile may be altered in the vastus lateralis of patients with mild COPD, normal body composition, and mildly impaired muscle function and exercise capacity. In vastus lateralis (VL) of mild COPD patients with well-preserved body composition and in healthy age-matched controls, expression of DNA methylation, muscle-enriched microRNAs, histone acetyltransferases (HTAs) and deacetylases (HDACs), protein acetylation, small ubiquitin-related modifier (SUMO) ligases, and muscle structure were explored. All subjects were clinically evaluated. Compared to healthy controls, in the VL of mild COPD patients, muscle function and exercise capacity were moderately reduced, DNA methylation levels did not differ, miR-1 expression levels were increased and positively correlated with both forced expiratory volume in one second (FEV₁) and quadriceps force, HDAC4 protein levels were increased, and muscle fiber types and sizes were not different. Moderate skeletal muscle dysfunction is a relevant feature in patients with mild COPD and preserved body composition. Several epigenetic events are differentially expressed in the limb muscles of these patients, probably as an attempt to counterbalance the underlying mechanisms that alter muscle function and mass. The study of patients at early stages of their disease is of interest as they are a target for timely therapeutic interventions that may slow down the course of the disease and prevent the deleterious effects of major comorbidities.

Chronic Obstructive Pulmonary Disease: official diagnosis and treatment guidelines of the Czech Pneumological and Phthisiological Society; a novel phenotypic approach to COPD with patient-oriented care

BACKGROUND

COPD is a global concern. Currently, several sets of guidelines, statements and strategies to managing COPD exist around the world.

METHODS

The Czech Pneumological and Phthisiological Society (CPPS) has commissioned an Expert group to draft recommended guidelines for the management of stable COPD. Subsequent revisions were further discussed at the National Consensus Conference (NCC). Reviewers' comments contributed to the establishment of the document's final version.

DIAGNOSIS

The hallmark of the novel approach to COPD is the integrated evaluation of the patient's lung functions, symptoms, exacerbations and identifications of clinical phenotype(s). The CPPS defines 6 clinically relevant phenotypes: frequent exacerbator, COPD-asthma overlap, COPD-bronchiectasis overlap, emphysematic phenotype, bronchitic phenotype and pulmonary cachexia phenotype.

TREATMENT

Treatment recommendations can be divided into four steps. 1(st) step = Risk exposure elimination: reduction of smoking and environmental tobacco smoke (ETS), decrease of home and occupational exposure risks. 2(nd) step = Standard treatment: inhaled bronchodilators, regular physical activity, pulmonary rehabilitation, education, inhalation training, comorbidity treatment, vaccination. 3(rd) step = Phenotype-specific therapy: PDE4i, ICS+LABA, LVRS, BVR, AAT augmentation, physiotherapy, mucolytic, ABT. 4(th) step = Care for respiratory insufficiency and terminal COPD: LTOT, lung transplantation, high intensity-NIV and palliative care.

CONCLUSION

Optimal treatment of COPD patients requires an individualised, multidisciplinary approach to the patient's symptoms, clinical phenotypes, needs and wishes. The new Czech COPD guideline reflects and covers these requirements.

Medical emergencies: pulmonary embolism and acute severe asthma

In this, the second of two articles covering specific medical emergencies, we discuss the definitions, epidemiology, pathophysiology, acute and chronic management of pulmonary embolus and acute severe asthma.