Chronic obstructive pulmonary disease phenotypes: the future of COPD

Outcome of pulmonary rehabilitation in COPD patients with severely impaired health status

INTRODUCTION

Effects of pulmonary rehabilitation (PR) in chronic obstructive pulmonary disease (COPD) patients with severely impaired health status are poorly documented since these patients are usually excluded from clinical trials. This retrospective, observational study aims to study the impact of disease on health status and the effects of PR on COPD patients referred to a tertiary center for PR in The Netherlands.

METHODS

Between June 2006 and June 2010, 437 patients with COPD were allocated to our intensive, comprehensive PR program. Patients participated in this interdisciplinary program for 12 weeks for a weekly average of 20-25 hours. Before and directly after, several measures of physical performance and health-related quality of life were determined.

RESULTS

At baseline, most patients (75%) had a Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage of III-IV. Peak exercise performance on a cycle ergometer was on average reduced to 43 ± 29 Watt, and health-related quality of life was significantly impaired, with a total score on the St George's Respiratory Questionnaire (SGRQ) of 66. Health-care utilization in the year preceding PR was very high. After rehabilitation, all outcome measures improved statistically significantly (P < 0.001). Exercise performance measured with the 6 minute walking distance test improved clinically significantly in 68% of the patients, whereas 75% of the patients showed a clinically meaningful improvement in quality of life as measured with the SGRQ. Multiple regression analysis revealed that 19% of the variation in responses on the 6 minute walking distance test and the SGRQ could be explained on the basis of baseline characteristics.

CONCLUSION

The present study provides data to indicate that COPD patients may substantially benefit from rehabilitation in a tertiary pulmonary rehabilitation center, despite a severely impaired health status and high level of health-care utilization, in which prior treatment in primary and secondary care have failed to improve health status. Individual rehabilitation responses can only partially be predicted on the basis of baseline characteristics. Consequently, no firm conclusions can be drawn from this study with respect to the selection of candidates that could be deemed eligible for this rehabilitation program when entering the program.

Hoover's sign is a predictor of airflow obstruction severity and is not related to hyperinflation in chronic obstructive pulmonary disease

BACKGROUND

Several phenotypes are described in COPD.

OBJECTIVES

To assess if COPD patients with Hoover's sign (HS) belong to a particular phenotype.

METHODS

All consecutive COPD patients with varying degree of airflow obstruction that came for lung function testing in one university hospital were prospectively assessed, using clinical and magnetometer detection of HS, body mass index (BMI), St. George's Respiratory Questionnaire for health-related quality of life, six-minute-walk test (6MWT) with inspiratory capacity (IC) measurements and expiratory flow limitation (EFL) detection. Previous exacerbations were also reported.

RESULTS

82 patients were studied. Magnetometers confirmed HS in 56 of them, of which 79% (44/56) were detected by clinical assessment. HS (+) patients were older (64 ± 10 vs 59 ± 10 years, p=0.03), had a higher BMI (26 ± 5 vs 23 ± 4, p=0.04), a lower FEV1 (53% ± 18% vs 63% ± 18% pred, p=0.02) and a higher IC decrease at the end of 6MWT, (-19 ± 2 vs -7 ± 4% pred, p=0.003). A larger proportion of HS (+) patients also reported severe exacerbations during the past 2 years (39% vs 12% p=0.01). There was no statistical evidence that HS was related to hyperinflation and/or EFL.

CONCLUSION

The very simple clinical HS allows identifying a particular population of COPD patients of older age and higher BMI with a more severe airflow obstruction, increased dynamic hyperinflation during exercise and higher exacerbation frequency. These characteristics were not linked to hyperinflation or EFL.

Multidimensional prognostic indices for use in COPD patient care. A systematic review

Background

A growing number of prognostic indices for chronic obstructive pulmonary disease (COPD) is developed for clinical use. Our aim is to identify, summarize and compare all published prognostic COPD indices, and to discuss their performance, usefulness and implementation in daily practice.

Methods

We performed a systematic literature search in both Pubmed and Embase up to September 2010. Selection criteria included primary publications of indices developed for stable COPD patients, that predict future outcome by a multidimensional scoring system, developed for and validated with COPD patients only. Two reviewers independently assessed the index quality using a structured screening form for systematically scoring prognostic studies.

Results

Of 7,028 articles screened, 13 studies comprising 15 indices were included. Only 1 index had been explored for its application in daily practice. We observed 21 different predictors and 7 prognostic outcomes, the latter reflecting mortality, hospitalization and exacerbation. Consistent strong predictors were FEV₁ percentage predicted, age and dyspnoea. The quality of the studies underlying the indices varied between fairly poor and good. Statistical methods to assess the predictive abilities of the indices were heterogenic. They generally revealed moderate to good discrimination, when measured. Limitations: We focused on prognostic indices for stable disease only and, inevitably, quality judgment was prone to subjectivity.

Conclusions

We identified 15 prognostic COPD indices. Although the prognostic performance of some of the indices has been validated, they all lack sufficient evidence for implementation. Whether or not the use of prognostic indices improves COPD disease management or patients' health is currently unknown; impact studies are required to establish this.

Use of cluster analysis to describe desaturator phenotypes in COPD: correlations between pulmonary function tests and nocturnal oxygen desaturation

BACKGROUND

Significant heterogeneity of clinical presentation and disease progression exists within chronic obstructive pulmonary disease (COPD). Although forced expiratory volume in 1 second (FEV(1)) inadequately describes this heterogeneity, a clear alternative has not emerged. This article discusses and refines the concept of phenotyping desaturators in COPD and shows a possible pattern which could be used as a framework for future research.

RECENT FINDINGS

COPD is a complex condition with pulmonary and extrapulmonary manifestations. We suggest that COPD phenotypes should be associated with clinically meaningful outcomes. The innovation of COPD phenotyping is defined as COPD desaturators. Sleep-related hypoxemia and hypercapnia are well recognized in COPD and the development of systemic inflammation during sleep. These sleep-related changes predispose to nocturnal cardiac arrhythmias, pulmonary hypertension, and possibly death, particularly during acute exacerbations.

CONCLUSION

A more focused definition makes possible a classification of patients into two distinct subgroups for both clinical and research purposes. Establishing a common language for future research will facilitate our understanding and management of such diseases. Even if different treatment strategies have different outcomes for these groups, we will have confirmation, or otherwise, of the clinical value of cluster analysis. This knowledge could lead to pharmacological treatment and other interventions directed to specific phenotypic groups.

Current controversies and future perspectives in chronic obstructive pulmonary disease

Over the past decade there has been much research and interest in COPD. As a result, the understanding and management of the disease has improved significantly. Yet, there are many uncertainties and controversies that require further work. This review discusses these controversies and anticipates some of the changes that may occur in the near future in the field of COPD.

The Asthma-COPD Overlap Syndrome: A Common Clinical Problem in the Elderly

Many patients with breathlessness and chronic obstructive lung disease are diagnosed with either asthma, COPD, or—frequently—mixed disease. More commonly, patients with uncharacterized breathlessness are treated with therapies that target asthma and COPD rather than one of these diseases. This common practice represents the difficulty in distinguishing these disorders clinically, particularly in patients with a history that does not easily differentiate asthma from COPD. A common clinical scenario is an older former smoker with partially reversible or fixed airflow obstruction and evidence of atopy, demonstrating “overlap” features of asthma and COPD. We stress that asthma-COPD overlap syndrome becomes more prevalent with advancing age as patients respond less favorably to guideline-recommended drug therapy. We review the similarities and differences in clinical characteristics between these disorders, and their physiologic and inflammatory profiles within the context of the aging patient. We underscore the difficulties in differentiating asthma from COPD in current or former smokers, share our institutional experience with overlap syndrome, and highlight the need for new research to better characterize and investigate this important clinical phenotype.

[Treating COPD in chronic patients in a primary-care setting]

The aging of the populations in Western countries entails an increase in chronic diseases, which becomes evident with the triad of age, comorbidities and polymedication. chronic obstructive pulmonary disease represents one of the most important causes of morbidity and mortality, with a prevalence in Spain of 10.2% in the population aged 40 to 80. In recent years, it has come to be defined not only as an obstructive pulmonary disease, but also as a systemic disease. Some aspects stand out in its management: smoking, the main risk factor, even though avoidable, is an important health problem; very important levels of underdiagnosis and little diagnostic accuracy, with inadequate use of spirometry; chronic patient profile; exacerbations that affect survival and cause repeated hospitalizations; mobilization of numerous health-care resources; need to propose integral care (health-care education, rehabilitation, promotion of self-care and patient involvement in decision-making).

Proteomics in asthma and COPD phenotypes and endotypes for biomarker discovery and improved understanding of disease entities

The application of proteomics to respiratory diseases, such as asthma and COPD, has been limited compared to other fields, like cancer. Both asthma and COPD are recognised to be multi-factorial and complex diseases, both consisting of clusters of multiple disease phenotypes. The complexity of these diseases combined with the inaccessibility and invasiveness of disease relevant samples have provided a hurdle to the progress of respiratory proteomics. Advances in proteomic instrumentation and methodology have led to the possibility to identify proteomes in much smaller quantities of biological material. This review focuses on the efforts in respiratory proteomics in relation to asthma and COPD, and the importance of identifying subgroups of disease entities to establish appropriate biomarkers, and to enhance the understanding of underlying mechanisms in each subgroup. Careful phenotype characterisation of patient subpopulations is required to make improvement in the field of heterogeneous diseases such as asthma and COPD, and the clusters of phenotypes are likely to encompass subgroups of disease with distinct molecular mechanisms; endotypes. The utilisation of modern advanced proteomics in endotypes of asthma and COPD will likely contribute to the increased understanding of disease mechanisms, establishment of biomarkers for these endotypes and improved patient care.

Characteristics of Dutch and Swiss primary care COPD patients - baseline data of the ICE COLD ERIC study

Introduction

International Collaborative Effort on Chronic Obstructive Lung Disease: Exacerbation Risk Index Cohorts (ICE COLD ERIC) is a prospective cohort study with chronic obstructive pulmonary disease (COPD) patients from Switzerland and The Netherlands designed to develop and validate practical COPD risk indices that predict the clinical course of COPD patients in primary care. This paper describes the characteristics of the cohorts at baseline.

Material and methods

Standardized assessments included lung function, patient history, self-administered questionnaires, exercise capacity, and a venous blood sample for analysis of biomarkers and genetics.

Results

A total of 260 Dutch and 151 Swiss patients were included. Median age was 66 years, 57% were male, 38% were current smokers, 55% were former smokers, and 76% had at least one and 40% had two or more comorbidities with cardiovascular disease being the most prevalent one. The use of any pulmonary and cardiovascular drugs was 84% and 66%, respectively. Although lung function results (median forced expiratory volume in 1 second [FEV₁] was 59% of predicted) were similar across the two cohorts, Swiss patients reported better COPD-specific health-related quality of life (Chronic Respiratory Questionnaire) and had higher exercise capacity.

Discussion

COPD patients in the ICE COLD ERIC study represent a wide range of disease severities and the prevalence of multimorbidity is high. The rich variation in these primary care cohorts offers good opportunities to learn more about the clinical course of COPD.

Pre- and post-bronchodilator lung function as predictors of mortality in the Lung Health Study

Background

Chronic obstructive pulmonary disease (COPD) is supposed to be classified on the basis of post-bronchodilator lung function. Most longitudinal studies of COPD, though, do not have post-bronchodilator lung function available. We used pre-and post bronchodilator lung function data from the Lung Health Study to determine whether these measures differ in their ability to predict mortality.

Methods

We limited our analysis to subjects who were of black or white race, on whom we had complete data, and who participated at either the 1 year or the 5 year follow-up visit. We classified subjects based on their baseline lung function, according to COPD Classification criteria using both pre- and post-bronchodilator lung function. We conducted a survival analysis and logistic regression predicting death and controlling for age, sex, race, treatment group, smoking status, and measures of lung function (either pre- or post-bronchodilator. We calculated hazard ratios (HR) with 95% confidence intervals (CI) and also calculated area under the curve for the logistic regression models.

Results

By year 15 of the study, 721 of the original 5,887 study subjects had died. In the year 1 sample survival models, a higher FEV₁ % predicted lower mortality in both the pre-bronchodilator (HR 0.87, 95% CI 0.81, 0.94 per 10% increase) and post-bronchodilator (HR 0.84, 95% CI 0.77, 0.90) models. The area under the curve for the respective models was 69.2% and 69.4%. Similarly, using categories, when compared to people with "normal" lung function, subjects with Stage 3 or 4 disease had similar mortality in both the pre- (HR 1.51, 95% CI 0.75, 3.03) and post-bronchodilator (HR 1.45, 95% CI 0.41, 5.15) models. In the year 5 sample, when a larger proportion of subjects had Stage 3 or 4 disease (6.4% in the pre-bronchodilator group), mortality was significantly increased in both the pre- (HR 2.68, 95% CI 1.51, 4.75) and post-bronchodilator (HR 2.46, 95% CI 1.63, 3.73) models.

Conclusions

Both pre- and post-bronchodilator lung function predicted mortality in this analysis with a similar degree of accuracy. Post-bronchodilator lung function may not be needed in population studies that predict long-term outcomes.

The future of chronic obstructive pulmonary disease treatment--difficulties of and barriers to drug development

Although chronic obstructive pulmonary disease (COPD) is a major global health problem with a rising incidence and morbidity, few pharmacotherapeutic advances have been made over the past several decades. The challenges of development of such agents are multifactorial and include rudimentary understanding of the biological genesis of human disease, inadequate in-vitro and in-vivo models, unvalidated biomarkers, inefficient physiological and clinical endpoints, and variable regulatory review worldwide. Blockade of various inflammatory pathways and mediators is a reasonable therapeutic strategy to alter the natural history of COPD. Substantial heterogeneity is evident with respect to clinical presentation, physiology, imaging, response to therapy, decline in lung function, and survival. Numerous endpoints have been proposed for clinical studies in COPD, with new approaches under study. The novel strategy that seems most promising is the use of biomarkers. We hope that with these approaches novel pharmacotherapies will be developed in the near future.

Controversies in treatment of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a chronic disorder with substantial comorbidity and major effects attributable to the high morbidity and mortality rates. Despite an increasing evidence base, some important controversies in COPD management still exist. The classic way to define COPD has been based on spirometric criteria, but more relevant diagnostic methods are needed that can be used to describe COPD severity and comorbidity. Initiation of interventions earlier in the natural history of the disease to slow disease progression is debatable, there are many controversies about the role of inhaled corticosteroids in the management of COPD, and long-term antibiotics for prevention of exacerbation have had a resurgence in interest. Novel therapeutic drugs are urgently needed for optimum management of the acute COPD exacerbation. COPD is a complex disease and consists of several clinically relevant phenotypes that in future will guide its management.

Profiling of sputum inflammatory mediators in asthma and chronic obstructive pulmonary disease

Background

Asthma and chronic obstructive pulmonary disease (COPD) display features of overlap in airway physiology and airway inflammation. Whether inflammatory phenotypes in airway disease describe similar mediator expression is unknown.

Objectives

To explore the relationship of airway inflammation and cytokine and chemokine expression in asthma and COPD.

Methods

Subjects with asthma and COPD (n = 54 and n = 49) were studied. Clinical characteristics and sputum were collected at entry into the study. A 2-step sputum processing method was performed for supernatant and cytospin preparation. Meso Scale Discovery and Luminex platforms were used to measure cytokines, chemokines and matrix metalloproteinase levels.

Results

Analytes sensitive to dithiothreitol (DTT) that had increased recovery in the 2-step sputum process were IL-1β, 4, 5, 10, 13, IFN-γ, TNFRI, GM-CSF, CCL2, 3, 4, 5, 13 and 17. There was a differential expression in IL-8, TNFRI and TNFRII between asthma and COPD [mean fold difference (95% CI): IL-8, 2.6 (1.3–5.4), p = 0.01; TNFRI, 2.1 (1.3–5.4), p = 0.03; TNFRII, 2.6 (1.2–5.6), p = 0.02]. In neutrophilic and eosinophilic airway inflammation, TNFα, TNFRI, TNFRII, IL-6, IL-8 and IL-5 could differentiate between these phenotypes. However, these phenotypes were unrelated to the diagnosis of asthma or COPD.

Conclusion

Recovery of sputum mediators sensitive to DTT can be improved using the described sputum processing technique. Within airway inflammatory sub-phenotypes there is a differential pattern of mediator expression that is independent of disease. Whether these inflammatory phenotypes in asthma and COPD confer distinct pathogeneses, therapeutic responses and clinical phenotypes needs to be further evaluated.

The role of CT scanning in multidimensional phenotyping of COPD

BACKGROUND

COPD is a heterogeneous disease characterized by airflow obstruction and diagnosed by lung function. CT imaging is emerging as an important, noninvasive tool in phenotyping COPD. However, the use of CT imaging in defining the disease heterogeneity above lung function is not fully known.

METHODS

Seventy-five patients with COPD (58 men, 17 women) were studied with CT imaging and with measures of airway inflammation. Airway physiology and health status were also determined.

RESULTS

The presence of emphysema (EM), bronchiectasis (BE), and bronchial wall thickening (BWT) was found in 67%, 27%, and 27% of subjects, respectively. The presence of EM was associated with lower lung function (mean difference % FEV(1), -20%; 95% CI, -28 to -11; P < .001). There was no difference in airway inflammation, exacerbation frequency, or bacterial load in patients with EM alone or with BE and/or BWT ± EM. The diffusing capacity of the lung for carbon monoxide/alveolar volume ratio was the most sensitive and specific parameter in identifying EM (area under the receiver operator characteristic curve, 0.87; 95% CI, 0.79-0.96). Physiologic cluster analysis identified three clusters, two of which were EM predominant and the third characterized by a heterogeneous combination of EM and BE.

CONCLUSIONS

The application of CT imaging can be useful as a tool in the multidimensional approach to phenotyping patients with COPD.

Chronic obstructive pulmonary disease exacerbations in the COPDGene study: associated radiologic phenotypes

PURPOSE

To test the hypothesis-given the increasing emphasis on quantitative computed tomographic (CT) phenotypes of chronic obstructive pulmonary disease (COPD)-that a relationship exists between COPD exacerbation frequency and quantitative CT measures of emphysema and airway disease.

MATERIALS AND METHODS

This research protocol was approved by the institutional review board of each participating institution, and all participants provided written informed consent. One thousand two subjects who were enrolled in the COPDGene Study and met the GOLD (Global Initiative for Chronic Obstructive Lung Disease) criteria for COPD with quantitative CT analysis were included. Total lung emphysema percentage was measured by using the attenuation mask technique with a -950-HU threshold. An automated program measured the mean wall thickness and mean wall area percentage in six segmental bronchi. The frequency of COPD exacerbation in the prior year was determined by using a questionnaire. Statistical analysis was performed to examine the relationship of exacerbation frequency with lung function and quantitative CT measurements.

RESULTS

In a multivariate analysis adjusted for lung function, bronchial wall thickness and total lung emphysema percentage were associated with COPD exacerbation frequency. Each 1-mm increase in bronchial wall thickness was associated with a 1.84-fold increase in annual exacerbation rate (P = .004). For patients with 35% or greater total emphysema, each 5% increase in emphysema was associated with a 1.18-fold increase in this rate (P = .047).

CONCLUSION

Greater lung emphysema and airway wall thickness were associated with COPD exacerbations, independent of the severity of airflow obstruction. Quantitative CT can help identify subgroups of patients with COPD who experience exacerbations for targeted research and therapy development for individual phenotypes.

Exhaled nitric oxide and clinical phenotypes of childhood asthma

Whether exhaled NO helps to identify a specific phenotype of asthmatic patients remains debated. Our aims were to evaluate whether exhaled NO (FENO(0.05)) is independently associated (1) with underlying pathophysiological characteristics of asthma such as airway tone (bronchodilator response) and airway inflammation (inhaled corticosteroid [ICS]-dependant inflammation), and (2) with clinical phenotypes of asthma.We performed multivariate (exhaled NO as dependent variable) and k-means cluster analyses in a population of 169 asthmatic children (age ± SD: 10.5 ± 2.6 years) recruited in a monocenter cohort that was characterized in a cross-sectional design using 28 parameters describing potentially different asthma domains: atopy, environment (tobacco), control, exacerbations, treatment (inhaled corticosteroid and long-acting bronchodilator agonist), and lung function (airway architecture and tone). Two subject-related characteristics (height and atopy) and two disease-related characteristics (bronchodilator response and ICS dose > 200 μg/d) explained 36% of exhaled NO variance. Nine domains were isolated using principal component analysis. Four clusters were further identified: cluster 1 (47%): boys, unexposed to tobacco, with well-controlled asthma; cluster 2 (26%): girls, unexposed to tobacco, with well-controlled asthma; cluster 3 (6%): girls or boys, unexposed to tobacco, with uncontrolled asthma associated with increased airway tone, and cluster 4 (21%): girls or boys, exposed to parental smoking, with small airway to lung size ratio and uncontrolled asthma. FENO(0.05) was not different in these four clusters.In conclusion, FENO(0.05) is independently linked to two pathophysiological characteristics of asthma (ICS-dependant inflammation and bronchomotor tone) but does not help to identify a clinically relevant phenotype of asthmatic children.

A hypothesis to phenotype COPD exacerbations by aetiology

COPD exacerbations have traditionally been defined on the basis of symptoms or health-care utilization without specific reference to the suspected aetiology. Consequently, the term 'exacerbation' has been used to include all patients experiencing an acute deterioration of symptoms associated with COPD. However, exacerbations are known to result from a variety of causes and do not necessarily constitute an equivalent event in the same patient, between different patients or between individual research studies. We therefore hypothesize that phenotyping exacerbations by aetiology may identify exacerbation subgroups, clarify benefits of therapeutic intervention in the subgroups and overall improve clinical care. An acronym is proposed to facilitate phenotyping COPD exacerbations.

The multiple dimensions of airways disease: targeting treatment to clinical phenotypes

PURPOSE OF REVIEW

The recognition that asthma and chronic obstructive pulmonary disease (COPD) are not single diseases, but syndromes made up of multiple separate disorders that overlap, has led to attempts to develop a new taxonomy for the disorders of airflow obstruction. A better understanding of the distinct disorders of airways disease has the potential to inform on underlying mechanisms, risk factors, natural history, monitoring and treatment.

RECENT FINDINGS

Recent attempts to describe the different phenotypes have largely been based on cluster analysis. Preliminary evidence suggests that there may be five distinct phenotypes of airways disease. To date, however, no simple allocation criteria have been validated that enable clinicians to allocate individual patients to specific phenotypic groups. The concept of differential treatment responses in different phenotypes of airways disease has been established with the demonstration that eosinophilic asthma preferentially responds to inhaled corticosteroid therapy or monoclonal antibody against interleukin-5, and severe refractory noneosinophilic asthma to macrolide antibiotics.

SUMMARY

The priority is to further define the distinct phenotypes that make up the syndromes of asthma and COPD. This knowledge could lead to treatments specifically targeted for defined phenotypic groups, rather than for asthma and COPD in general, which represents the current management approach.

Disability in COPD and its relationship to clinical and patient-reported outcomes

OBJECTIVE

To assess the presence of disability in chronic obstructive pulmonary disease (COPD) patients and its relationships with disease severity, comorbidities, and patient-reported outcomes.

RESEARCH DESIGN AND METHOD

COPD outpatients completed validated questionnaires designed to investigate illness perception, well-being, quality of life, and stress, while physicians collected data concerning disability, dyspnea, and comorbidities (Charlson Index).

RESULTS

Of 164 patients, 37.3% exhibited a degree of disability and 67.7 % of them reported the loss of at least one relevant function in daily life (mean 2.34 ± 2.41). Although disability was associated with disease severity (χ(2) = 8.292; p < 0.016), disability was present to some degree in all disease stages and in 44.9% of patients with moderate COPD. Barthel Index scores were related to MRC scores (r = 0.529; p < 0.001), GOLD stage (r = 0.223; p < 0.006), and Charlson Index (r = 0.163; p < 0.032). Disabled patients had a lower mean FEV(1) value (50.96 ± 20.99 vs. 65.00 ± 23.63; p < 0.001) than self-sufficient patients (p < 0.001). The stepwise regression analysis showed that the MRC score was the most relevant factor in inducing COPD patient disability (F = 56.5; p = 0.001). Compared to self-sufficient patients, disabled patients reported lower levels of well-being and health status, increased levels of distress, and a different illness perception.

CONCLUSIONS

Disability can be identified in each disease stage, with dyspnea serving as the most relevant inducing factor. Since disability substantially impacts patient perception of and experience with COPD, its presence must be taken into account during disease management. The cross-sectional nature of the study and the characteristics of the sample size represent a limitation in the possibility to generalize the results.

Cross-sectional analysis of the utility of pulmonary function tests in predicting emphysema in ever-smokers

Emphysema is largely an under-diagnosed medical condition that can exist in smokers in the absence of airway obstruction. We aimed to determine the sensitivity and specificity of pulmonary function tests (PFTs) in assessing emphysema using quantitative CT scans as the reference standard. We enrolled 224 ever-smokers (current or former) over the age of 40. CT of thorax was used to quantify the low attenuation area (% emphysema), and to measure the standardized airway wall thickness. PFTs were used individually and in combination to predict their ability to discriminate radiographic emphysema. Significant emphysema (>7%) was detected in 122 (54%) subjects. Twenty six (21%) emphysema subjects had no evidence of airflow obstruction (FEV(1)/FVC ratio <70%), while all subjects with >23% emphysema showed airflow obstruction. The sensitivity and specificity of spirometry for detecting radiographic emphysema were 79% and 75%, respectively. Standardized airway wall thickness was increased in subjects with airflow obstruction, but did not correlate with emphysema severity. In this cohort of lifetime ever-smokers, PFTs alone were inadequate for diagnosing emphysema. Airway wall thickness quantified by CT morphometry was associated with airflow limitation, but not with emphysema indicating that the heterogeneous nature of lung disease in smokers may represent distinct phenotypes.

Systemic manifestations of COPD

COPD is characterized by a poorly reversible airflow limitation resulting from chronic inflammation, mainly due to tobacco exposure. Over the past few years, the understanding of COPD has evolved from it being a disease affecting the lungs to it being a complex, heterogeneous, and generalized disorder in an aging population. Extrapulmonary comorbidities significantly complicate the management and influence the prognosis of patients with COPD. Although certain comorbidities like cardiovascular diseases share some risk factors with COPD, such as cigarette smoking, other frequently observed comorbidities, including musculoskeletal wasting, metabolic syndrome, and depression, cannot be easily attributed to smoking. There is increasing evidence that chronic inflammation is a key factor in COPD and that inflammation might be the common pathway linking these comorbidities and explaining why they typically develop together. Physicians treating patients with COPD need to become aware of these extrapulmonary aspects. Any patient with COPD should be carefully evaluated for comorbidities and the systemic consequences of COPD since they not only influence the prognosis but also have an impact on disease management. The treatment of COPD is no longer focused exclusively on inhaled therapy but is taking on a multidimensional approach, especially because the treatment of the comorbidities might positively affect the course of COPD itself.

Reduction of exacerbations by the PDE4 inhibitor roflumilast--the importance of defining different subsets of patients with COPD

BACKGROUND

As chronic obstructive pulmonary disease (COPD) is a heterogeneous disease it is unlikely that all patients will benefit equally from a given therapy. Roflumilast, an oral, once-daily phosphodiesterase 4 inhibitor, has been shown to improve lung function in moderate and severe COPD but its effect on exacerbations in unselected populations was inconclusive. This led to the question of whether a responsive subset existed that could be investigated further.

METHODS

The datasets of two previous replicate, randomized, double-blind, placebo-controlled, parallel-group studies (oral roflumilast 500 μg or placebo once daily for 52 weeks) that were inconclusive regarding exacerbations were combined in a post-hoc, pooled analysis to determine whether roflumilast reduced exacerbations in a more precisely defined patient subset.

RESULTS

The pooled analysis included 2686 randomized patients. Roflumilast significantly decreased exacerbations by 14.3% compared with placebo (p = 0.026). Features associated with this reduction were: presence of chronic bronchitis with or without emphysema (26.2% decrease, p = 0.001), presence of cough (20.9% decrease, p = 0.006), presence of sputum (17.8% decrease, p = 0.03), and concurrent use of inhaled corticosteroids (ICS; 18.8% decrease, p = 0.014). The incidence of adverse events was similar with roflumilast and placebo (81.5% vs 80.1%), but more patients in the roflumilast group had events assessed as likely or definitely related to the study drug (21.5% vs 8.3%).

CONCLUSIONS

This post-hoc, pooled analysis showed that roflumilast reduced exacerbation frequency in a subset of COPD patients whose characteristics included chronic bronchitis with/without concurrent ICS. These observations aided the design of subsequent phase 3 studies that prospectively confirmed the reduction in exacerbations with roflumilast treatment.

TRIALS REGISTRATION

ClinicalTrials.gov identifiers: NCT00076089 and NCT00430729.

P4 medicine: the future around the corner

Traditional medical practice has been "reactive" (doctor takes part when disease appears). The theoretical (scale free networks and complex systems), technological (high efficiency "omic" technologies) and conceptual (biology systems) advances throughout the last decade, allow us to anticipate the transition to an "anticipatory" medicine, based on health (not on disease). This review establishes the conceptual bases and discusses the principal aspects of this new medicine, known as "P4 Medicine" standing for personalized, predictive, preventive and participatory.

Addressing the complexity of chronic obstructive pulmonary disease: from phenotypes and biomarkers to scale-free networks, systems biology, and P4 medicine

Chronic obstructive pulmonary disease (COPD) is a complex disease at the clinical, cellular, and molecular levels. However, its diagnosis, assessment, and therapeutic management are based almost exclusively on the severity of airflow limitation. A better understanding of the multiple dimensions of COPD and its relationship to other diseases is very relevant and of high current interest. Recent theoretical (scale-free networks), technological (high-throughput technology, biocomputing), and analytical improvements (systems biology) provide tools capable of addressing the complexity of COPD. The information obtained from the integrated use of those techniques will be eventually incorporated into routine clinical practice. This review summarizes our current knowledge in this area and offers an insight into the elements needed to progress toward an integrated, multilevel view of COPD based on the novel scientific strategy of systems biology and its potential clinical derivative, P4 medicine (Personalized, Predictive, Preventive, and Participatory).

Characterisation of COPD heterogeneity in the ECLIPSE cohort

Background

Chronic obstructive pulmonary disease (COPD) is a complex condition with pulmonary and extra-pulmonary manifestations. This study describes the heterogeneity of COPD in a large and well characterised and controlled COPD cohort (ECLIPSE).

Methods

We studied 2164 clinically stable COPD patients, 337 smokers with normal lung function and 245 never smokers. In these individuals, we measured clinical parameters, nutritional status, spirometry, exercise tolerance, and amount of emphysema by computed tomography.

Results

COPD patients were slightly older than controls and had more pack years of smoking than smokers with normal lung function. Co-morbidities were more prevalent in COPD patients than in controls, and occurred to the same extent irrespective of the GOLD stage. The severity of airflow limitation in COPD patients was poorly related to the degree of breathlessness, health status, presence of co-morbidity, exercise capacity and number of exacerbations reported in the year before the study. The distribution of these variables within each GOLD stage was wide. Even in subjects with severe airflow obstruction, a substantial proportion did not report symptoms, exacerbations or exercise limitation. The amount of emphysema increased with GOLD severity. The prevalence of bronchiectasis was low (4%) but also increased with GOLD stage. Some gender differences were also identified.

Conclusions

The clinical manifestations of COPD are highly variable and the degree of airflow limitation does not capture the heterogeneity of the disease.