Walking exercise response to bronchodilation in mild COPD: A randomized trial

Treatment Trials in Young Patients with Chronic Obstructive Pulmonary Disease and Pre-Chronic Obstructive Pulmonary Disease Patients: Time to Move Forward

Chronic obstructive pulmonary disease (COPD) is the end result of a series of dynamic and cumulative gene-environment interactions over a lifetime. The evolving understanding of COPD biology provides novel opportunities for prevention, early diagnosis, and intervention. To advance these concepts, we propose therapeutic trials in two major groups of subjects: "young" individuals with COPD and those with pre-COPD. Given that lungs grow to about 20 years of age and begin to age at approximately 50 years, we consider "young" patients with COPD those patients in the age range of 20-50 years. Pre-COPD relates to individuals of any age who have respiratory symptoms with or without structural and/or functional abnormalities, in the absence of airflow limitation, and who may develop persistent airflow limitation over time. We exclude from the current discussion infants and adolescents because of their unique physiological context and COPD in older adults given their representation in prior randomized controlled trials (RCTs). We highlight the need of RCTs focused on COPD in young patients or pre-COPD to reduce disease progression, providing innovative approaches to identifying and engaging potential study subjects. We detail approaches to RCT design, including potential outcomes such as lung function, patient-reported outcomes, exacerbations, lung imaging, mortality, and composite endpoints. We critically review study design components such as statistical powering and analysis, duration of study treatment, and formats to trial structure, including platform, basket, and umbrella trials. We provide a call to action for treatment RCTs in 1) young adults with COPD and 2) those with pre-COPD at any age.

Diagnosis and Treatment of Early Chronic Obstructive Lung Disease (COPD)

Chronic obstructive lung disease (COPD) is responsible for substantial rates of mortality and economic burden, and is one of the most important public-health concerns. As the disease characteristics include irreversible airway obstruction and progressive lung function decline, there has been a great deal of interest in detection at the early stages of COPD during the “at risk” or undiagnosed preclinical stage to prevent the disease from progressing to the overt stage. Previous studies have used various definitions of early COPD, and the term mild COPD has also often been used. There has been a great deal of recent effort to establish a definition of early COPD, but comprehensive evaluation is still required, including identification of risk factors, various physiological and radiological tests, and clinical manifestations for diagnosis of early COPD, considering the heterogeneity of the disease. The treatment of early COPD should be considered from the perspective of prevention of disease progression and management of clinical deterioration. There has been a lack of studies on this topic as the definition of early COPD has been proposed only recently, and therefore further clinical studies are needed.

Weighing the evidence for pharmacological treatment interventions in mild COPD; a narrative perspective

There is increasing focus on understanding the nature of chronic obstructive pulmonary disease (COPD) during the earlier stages. Mild COPD (Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage 1 or the now-withdrawn GOLD stage 0) represents an early stage of COPD that may progress to more severe disease. This review summarises the disease burden of patients with mild COPD and discusses the evidence for treatment intervention in this subgroup.

Overall, patients with mild COPD suffer a substantial disease burden that includes persistent or potentially debilitating symptoms, increased risk of exacerbations, increased healthcare utilisation, reduced exercise tolerance and physical activity, and a higher rate of lung function decline versus controls. However, the evidence for treatment efficacy in these patients is limited due to their frequent exclusion from clinical trials. Careful assessment of disease burden and the rate of disease progression in individual patients, rather than a reliance on spirometry data, may identify patients who could benefit from earlier treatment intervention.

The Link between Reduced Inspiratory Capacity and Exercise Intolerance in Chronic Obstructive Pulmonary Disease

Low inspiratory capacity (IC), chronic dyspnea, and reduced exercise capacity are inextricably linked and are independent predictors of increased mortality in chronic obstructive pulmonary disease. It is no surprise, therefore, that a major goal of management is to improve IC by reducing lung hyperinflation to improve respiratory symptoms and health-related quality of life. The negative effects of lung hyperinflation on respiratory muscle and cardiocirculatory function during exercise are now well established. Moreover, there is growing appreciation that a key mechanism of exertional dyspnea in chronic obstructive pulmonary disease is critical mechanical constraints on tidal volume expansion during exercise when resting IC is reduced. Further evidence for the importance of lung hyperinflation comes from multiple studies, which have reported the clinical benefits of therapeutic interventions that reduce lung hyperinflation and increase IC. A reduced IC in obstructive pulmonary disease is further eroded by exercise and contributes to ventilatory limitation and dyspnea. It is an important outcome for both clinical and research studies.

Exertional dyspnoea in COPD: the clinical utility of cardiopulmonary exercise testing

Activity-related dyspnoea is often the most distressing symptom experienced by patients with chronic obstructive pulmonary disease (COPD) and can persist despite comprehensive medical management. It is now clear that dyspnoea during physical activity occurs across the spectrum of disease severity, even in those with mild airway obstruction. Our understanding of the nature and source of dyspnoea is incomplete, but current aetiological concepts emphasise the importance of increased central neural drive to breathe in the setting of a reduced ability of the respiratory system to appropriately respond. Since dyspnoea is provoked or aggravated by physical activity, its concurrent measurement during standardised laboratory exercise testing is clearly important. Combining measurement of perceptual and physiological responses during exercise can provide valuable insights into symptom severity and its pathophysiological underpinnings. This review summarises the abnormal physiological responses to exercise in COPD, as these form the basis for modern constructs of the neurobiology of exertional dyspnoea. The main objectives are: 1) to examine the role of cardiopulmonary exercise testing (CPET) in uncovering the physiological mechanisms of exertional dyspnoea in patients with mild-to-moderate COPD; 2) to examine the escalating negative sensory consequences of progressive respiratory impairment with disease advancement; and 3) to build a physiological rationale for individualised treatment optimisation based on CPET.

Use of exercise testing in the evaluation of interventional efficacy: an official ERS statement

This document reviews 1) the measurement properties of commonly used exercise tests in patients with chronic respiratory diseases and 2) published studies on their utilty and/or evaluation obtained from MEDLINE and Cochrane Library searches between 1990 and March 2015.

Exercise tests are reliable and consistently responsive to rehabilitative and pharmacological interventions. Thresholds for clinically important changes in performance are available for several tests. In pulmonary arterial hypertension, the 6-min walk test (6MWT), peak oxygen uptake and ventilation/carbon dioxide output indices appear to be the variables most responsive to vasodilators. While bronchodilators do not always show clinically relevant effects in chronic obstructive pulmonary disease, high-intensity constant work-rate (endurance) tests (CWRET) are considerably more responsive than incremental exercise tests and 6MWTs. High-intensity CWRETs need to be standardised to reduce interindividual variability. Additional physiological information and responsiveness can be obtained from isotime measurements, particularly of inspiratory capacity and dyspnoea. Less evidence is available for the endurance shuttle walk test. Although the incremental shuttle walk test and 6MWT are reliable and less expensive than cardiopulmonary exercise testing, two repetitions are needed at baseline. All exercise tests are safe when recommended precautions are followed, with evidence suggesting that no test is safer than others.

Recent updates in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), characterized by chronic airways inflammation and progressive airflow limitation, is a common, preventable and treatable disease. Worldwide, COPD is a major cause of morbidity and mortality; smoking tobacco is the most important risk factor. This translational review of recent updates in COPD care for the primary care audience, includes recommendations from the 2015 Global Initiative for chronic obstructive lung disease (GOLD) report on diagnosis, pharmacological and non-pharmacological treatment, prevalence of comorbidities, management of exacerbations and the asthma and COPD overlap syndrome, with a focus on the importance and benefit of physical activity and exercise in COPD patients. Exacerbations and comorbidities contribute to the overall severity of COPD in individual patients. Management of exacerbations includes reducing the impact of the current exacerbation and preventing development of subsequent episodes. Healthcare professionals need to be alert to comorbidities, such as cardiovascular disease, anxiety/depression, lung cancer, infections and diabetes, which are common in COPD patients and can have a significant impact on HRQoL and prognosis. Pulmonary rehabilitation is recommended by a number of guidelines for all symptomatic COPD patients, regardless of severity, and involves exercise training, patient education, nutritional advice and psychosocial support. At all stages of COPD, regular physical activity and exercise can aid symptom control, improve HRQoL, reduce rates of hospitalization, and improve morbidity and respiratory mortality. Healthcare professionals play a pivotal role in improving HRQoL and health-related outcomes in COPD patients to meet their specific needs and in providing appropriate diagnosis, management and advice on smoking cessation.

Cluster Analysis in Patients with GOLD 1 Chronic Obstructive Pulmonary Disease

Background

We hypothesized that heterogeneity exists within the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1 spirometric category and that different subgroups could be identified within this GOLD category.

Methods

Pre-randomization study participants from two clinical trials were symptomatic/asymptomatic GOLD 1 chronic obstructive pulmonary disease (COPD) patients and healthy controls. A hierarchical cluster analysis used pre-randomization demographics, symptom scores, lung function, peak exercise response and daily physical activity levels to derive population subgroups.

Results

Considerable heterogeneity existed for clinical variables among patients with GOLD 1 COPD. All parameters, except forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC), had considerable overlap between GOLD 1 COPD and controls. Three-clusters were identified: cluster I (18 [15%] COPD patients; 105 [85%] controls); cluster II (45 [80%] COPD patients; 11 [20%] controls); and cluster III (22 [92%] COPD patients; 2 [8%] controls). Apart from reduced diffusion capacity and lower baseline dyspnea index versus controls, cluster I COPD patients had otherwise preserved lung volumes, exercise capacity and physical activity levels. Cluster II COPD patients had a higher smoking history and greater hyperinflation versus cluster I COPD patients. Cluster III COPD patients had reduced physical activity versus controls and clusters I and II COPD patients, and lower FEV₁/FVC versus clusters I and II COPD patients.

Conclusions

The results emphasize heterogeneity within GOLD 1 COPD, supporting an individualized therapeutic approach to patients.

Trial registration

www.clinicaltrials.gov. NCT01360788 and NCT01072396.

New insights into the pathophysiology of mild chronic obstructive pulmonary disease

The classification of mild chronic obstructive pulmonary disease (COPD) requires a postbronchodilator forced expiratory volume in 1 s (FEV1) to forced vital capacity ratio <0.7 and an FEV1 ≥80% predicted. Given their relatively well-preserved spirometry, some have argued that respiratory symptoms in patients with mild COPD are unlikely to be related to pulmonary function abnormalities and that early detection of COPD is a 'waste of resources'. Despite this viewpoint, there is emerging clinical and physiological evidence of peripheral airway dysfunction, diminished quality of life and reduced physical activity levels, and increased mortality, hospitalizations, dyspnea and exercise intolerance in patients with mild COPD compared with healthy controls. The purpose of the present focused review was to summarize recent research regarding the pathophysiology and treatment of mild COPD.

Should mild COPD be treated? Evidence for early pharmacological intervention

Chronic obstructive pulmonary disease (COPD) is a common and often progressive inflammatory disease of the airways that is both preventable and treatable. It is well established that those with mild-to-moderate disease severity represent the majority of patients with COPD, yet this subpopulation is relatively under-studied. Because of an insidious pre-clinical phase, COPD is both under-diagnosed and under-treated. Recent studies have confirmed that even patients with mild, grade 1 COPD [i.e. those with a reduced forced expiratory volume in one second (FEV1)/forced vital capacity ratio but normal FEV1], have measurable physiological impairment with increased morbidity and a higher risk of mortality compared with non-smoking healthy controls. Beyond the imperative of smoking cessation-the pivotal intervention in all COPD stages-the role of pharmacotherapy for prevention of disease progression has yet to be established. The main objective of this review is to provide a concise overview of the heterogeneous pathophysiology of COPD with only mild airway obstruction on spirometry and obstacles for early diagnosis. We emphasize that the absence of sufficiently powered trials involving a large number of patients precludes definitive recommendations in support of (or against) long-term pharmacological treatment in mild COPD. Despite these limitations, we present a rationale for earlier pharmacological intervention derived from recent physiological studies performed in symptomatic patients with mild COPD.

Activity restriction in mild COPD: a challenging clinical problem

Dyspnea, exercise intolerance, and activity restriction are already apparent in mild chronic obstructive pulmonary disease (COPD). However, patients may not seek medical help until their symptoms become troublesome and persistent and significant respiratory impairment is already present; as a consequence, further sustained physical inactivity may contribute to disease progression. Ventilatory and gas exchange impairment, cardiac dysfunction, and skeletal muscle dysfunction are present to a variable degree in patients with mild COPD, and collectively may contribute to exercise intolerance. As such, there is increasing interest in evaluating exercise tolerance and physical activity in symptomatic patients with COPD who have mild airway obstruction, as defined by spirometry. Simple questionnaires, eg, the modified British Medical Research Council dyspnea scale and the COPD Assessment Test, or exercise tests, eg, the 6-minute or incremental and endurance exercise tests can be used to assess exercise performance and functional status. Pedometers and accelerometers are used to evaluate physical activity, and endurance tests (cycle or treadmill) using constant work rate protocols are used to assess the effects of interventions such as pulmonary rehabilitation. In addition, alternative outcome measurements, such as tests of small airway dysfunction and laboratory-based exercise tests, are used to measure the extent of physiological impairment in individuals with persistent dyspnea. This review describes the mechanisms of exercise limitation in patients with mild COPD and the interventions that can potentially improve exercise tolerance. Also discussed are the benefits of pulmonary rehabilitation and the potential role of pharmacologic treatment in symptomatic patients with mild COPD.

Pathogenesis of hyperinflation in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a preventable and treatable lung disease characterized by airflow limitation that is not fully reversible. In a significant proportion of patients with COPD, reduced lung elastic recoil combined with expiratory flow limitation leads to lung hyperinflation during the course of the disease. Development of hyperinflation during the course of COPD is insidious. Dynamic hyperinflation is highly prevalent in the advanced stages of COPD, and new evidence suggests that it also occurs in many patients with mild disease, independently of the presence of resting hyperinflation. Hyperinflation is clinically relevant for patients with COPD mainly because it contributes to dyspnea, exercise intolerance, skeletal muscle limitations, morbidity, and reduced physical activity levels associated with the disease. Various pharmacological and nonpharmacological interventions have been shown to reduce hyperinflation and delay the onset of ventilatory limitation in patients with COPD. The aim of this review is to address the more recent literature regarding the pathogenesis, assessment, and management of both static and dynamic lung hyperinflation in patients with COPD. We also address the influence of biological sex and obesity and new developments in our understanding of hyperinflation in patients with mild COPD and its evolution during progression of the disease.

Validation of the i-BODE index as a predictor of hospitalization and mortality in patients with COPD participating in pulmonary rehabilitation

Abstract The aim of this study was to examine the value of the i-BODE index to predict hospital admission and to confirm its usefulness to predict mortality in a Danish population. The incremental shuttle walking test (ISWT) is widely used in the UK and Europe and previous work has examined the replacement of the 6MWT with the ISWT within the BODE index for predicting the prognosis of COPD (i-BODE). The 674 patients included in the analysis participated in a 7-week pulmonary rehabilitation program from 2002 to 2011. The National Health Services Central Register ascertained vital status and provided information on all hospital admissions. The mean follow-up period was 66 months (range 11-118 months). Cox proportional hazards model was used to identify factors that significantly predicted mortality and time to first hospital admission. The i-BODE index as well as body mass index, MRC dyspnea grade, and exercise capacity (ISWT) were significantly associated with all-cause mortality. The adjusted hazard ratio for death per one point increase in the i-BODE score was 1.28 (95% confidence interval 1.20 to 1.37). The i-BODE index was also a significant predictor of hospitalization, both for all causes and COPD exacerbation. Patients in the highest i-BODE quartile had a median time to first hospitalization of 17 months compared to 51 months for patients in the lowest quartile. The i-BODE index is a significant predictor of hospital admission and thus health care utilization, and also mortality.