Sex Difference in Chronic Obstructive Lung Disease. Does it Matter? A Concise Review

Chronic obstructive lung disease (COPD) primarily affects men; however, its epidemiology has been changing because more women have become smokers. Recently, investigators found that although women and men were exposed to the same amount of smoke fume, women tended to have more severe disease and higher mortality rate. They also complain of more dyspnoea and may experience more severe exacerbations than men. This led to the question of whether sex has an impact on COPD course and whether women have a higher susceptibility to smoke fumes than men. That may be explained by multiple complex factors highlighting the relationship between sex, epidemiology, method of diagnostics and the clinical course of the disease. In this review, sex differences in epidemiology, clinical presentation, exacerbation, co-morbidities and treatment are covered.

Peripheral blood eosinophils: a surrogate marker for airway eosinophilia in stable COPD

Introduction

Sputum eosinophilia occurs in approximately one-third of stable chronic obstructive pulmonary disease (COPD) patients and can predict exacerbation risk and response to corticosteroid treatments. Sputum induction, however, requires expertise, may not always be successful, and does not provide point-of-care results. Easily applicable diagnostic markers that can predict sputum eosinophilia in stable COPD patients have the potential to progress COPD management. This study investigated the correlation and predictive relationship between peripheral blood and sputum eosinophils. It also examined the repeatability of blood eosinophil counts.

Methods

Stable COPD patients (n=141) were classified as eosinophilic or noneosinophilic based on their sputum cell counts (≥3%), and a cross-sectional analysis was conducted comparing their demographics, clinical characteristics, and blood cell counts. Receiver operating characteristic curve analysis was used to assess the predictive ability of blood eosinophils for sputum eosinophilia. Intraclass correlation coefficient was used to examine the repeatability of blood eosinophil counts.

Results

Blood eosinophil counts were significantly higher in patients with sputum eosinophilia (n=45) compared to those without (0.3×10⁹/L vs 0.15×10⁹/L; P<0.0001). Blood eosinophils correlated with both the percentage (ρ=0.535; P<0.0001) and number of sputum eosinophils (ρ=0.473; P<0.0001). Absolute blood eosinophil count was predictive of sputum eosinophilia (area under the curve =0.76, 95% confidence interval [CI] =0.67–0.84; P<0.0001). At a threshold of ≥0.3×10⁹/L (specificity =76%, sensitivity =60%, and positive likelihood ratio =2.5), peripheral blood eosinophil counts enabled identification of the presence or absence of sputum eosinophilia in 71% of the cases. A threshold of ≥0.4×10⁹/L had similar classifying ability but better specificity (91.7%) and higher positive likelihood ratio (3.7). In contrast, ≥0.2×10⁹/L offered a better sensitivity (91.1%) for ruling out sputum eosinophilia. There was a good agreement between two measurements of blood eosinophil count over a median of 28 days (intraclass correlation coefficient =0.8; 95% CI =0.66–0.88; P<0.0001).

Conclusion

Peripheral blood eosinophil counts can help identify the presence or absence of sputum eosinophilia in stable COPD patients with a reasonable degree of accuracy.

The effect of aclidinium bromide on daily respiratory symptoms of COPD, measured using the Evaluating Respiratory Symptoms in COPD (E-RS: COPD) diary: pooled analysis of two 6-month Phase III studies

BACKGROUND

Reducing the severity of respiratory symptoms is a key goal in the treatment of chronic obstructive pulmonary disease (COPD). We evaluated the effect of aclidinium bromide 400 μg twice daily (BID) on respiratory symptoms, assessed using the Evaluating Respiratory Symptoms in COPD (E-RS(™): COPD) scale (formerly EXACT-RS).

METHODS

Data were pooled from the aclidinium 400 μg BID and placebo arms of two 24-week, double-blind, randomized Phase III studies evaluating aclidinium monotherapy (ATTAIN) or combination therapy (AUGMENT COPD I) in patients with moderate to severe airflow obstruction. Patients were stratified by Global initiative for chronic Obstructive Lung Disease (GOLD) Groups A-D. Change from baseline in E-RS scores, proportion of responders (patients achieving pre-defined improvements in E-RS scores), and net benefit (patients who improved minus patients who worsened) were analyzed.

RESULTS

Of 1210 patients, 1167 had data available for GOLD classification. Mean (standard deviation) age was 63.2 (8.6) years, 60.7 % were male, and mean post-bronchodilator forced expiratory volume in 1 s was 54.4 % predicted. Compared with placebo, aclidinium 400 μg BID significantly improved RS-Total (2.38 units vs 0.79 units, p < 0.001) and domain scores (all p < 0.001) at Week 24, and doubled the likelihood of being an RS-Total score responder (p < 0.05), irrespective of GOLD group. The net benefit for RS-Total (Overall: 56.9 % vs 19.4 %; A + C: 65.7 % vs 6.3 %; B + D: 56.0 % vs 20.8 %, for aclidinium 400 μg BID and placebo respectively; all p < 0.05) and domain scores (all p < 0.05) was significantly greater with aclidinium compared with placebo, in both GOLD Groups A + C and B + D.

CONCLUSIONS

Aclidinium 400 μg BID significantly improved respiratory symptoms regardless of the patients' level of symptoms at baseline. Net treatment benefit was similar in patients with low or high levels of symptoms.

TRIAL REGISTRATION

ATTAIN (ClinicalTrials.gov identifier: NCT01001494 ) and AUGMENT COPD I (ClinicalTrials.gov identifier: NCT01437397 ).

An official American Thoracic Society/European Respiratory Society statement: research questions in COPD

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity, mortality and resource use worldwide. The goal of this official American Thoracic Society (ATS)/European Respiratory Society (ERS) Research Statement is to describe evidence related to diagnosis, assessment, and management; identify gaps in knowledge; and make recommendations for future research. It is not intended to provide clinical practice recommendations on COPD diagnosis and management.

Clinicians, researchers and patient advocates with expertise in COPD were invited to participate. A literature search of Medline was performed, and studies deemed relevant were selected. The search was not a systematic review of the evidence. Existing evidence was appraised and summarised, and then salient knowledge gaps were identified.

Recommendations for research that addresses important gaps in the evidence in all areas of COPD were formulated via discussion and consensus.

Great strides have been made in the diagnosis, assessment and management of COPD, as well as understanding its pathogenesis. Despite this, many important questions remain unanswered. This ATS/ERS research statement highlights the types of research that leading clinicians, researchers and patient advocates believe will have the greatest impact on patient-centred outcomes.

ATS/ERS statement highlighting research areas that will have the greatest impact on patient-centred outcomes in COPDhttp://ow.ly/LXW2J

Serum testosterone, testosterone replacement therapy and all-cause mortality in men with type 2 diabetes: retrospective consideration of the impact of PDE5 inhibitors and statins

BACKGROUND

Low testosterone levels occur in over 40% of men with type 2 diabetes mellitus (T2DM) and have been associated with increased mortality. Testosterone replacement together with statins and phosphodiesterase 5 inhibitors (PDE5I) are widely used in men with T2DM.

PURPOSE

To determine the impact of testosterone and testosterone replacement therapy (TRT) on mortality and assess the independence of this effect by adjusting statistical models for statin and PDE5I use.

METHODS

We studied 857 men with T2DM screened from five primary care practices during April 2007-April 2009. Of the 857 men, 175/637 men with serum total testosterone ≤ 12 nmol/l or free testosterone (FT) ≤ 0.25 nmol/l received TU for a mean of 3.8 ± 1.2 (SD) years. PDE5I and statins were prescribed to 175/857 and 662/857 men respectively. All-cause mortality was the primary end-point. Cox regression models were used to compare survival in the three testosterone level/treatment groups, the analysis adjusted for age, statin and PDE5I use, BMI, blood pressure and lipids.

RESULTS

Compared with the Low T/untreated group, mortality in the Normal T/untreated (HR: 0.62, CI: 0.41-0.94) or Low T/treated (HR: 0.38, CI: 0.16-0.90) groups was significantly reduced. PDE5I use was significantly associated with reduced mortality (HR: 0.21, CI: 0.066-0.68). After repeating the Cox regression in the 682 men not given a PDE5I, mortality in the Normal T/untreated and Low T/treated groups was significantly lower than that in the reference Low T/untreated group. Mortality in the PDE5I/treated was significantly reduced compared with the PDE5I/untreated group (OR: 0.06, CI: 0.009-0.47).

CONCLUSIONS

Testosterone replacement therapy is independently associated with reduced mortality in men with T2DM. PDE5I use, included as a confounding factor, was associated with decreased mortality in all patients and, those not on TRT, suggesting independence of effect. The impact of PDE5I treatment on mortality (both HR and OR < 0.25) needs confirmation by independent studies.

Metformin in severe exacerbations of chronic obstructive pulmonary disease: a randomised controlled trial

Background

Severe exacerbations of COPD are commonly associated with hyperglycaemia, which predicts adverse outcomes. Metformin is a well-established anti-hyperglycaemic agent in diabetes mellitus, possibly augmented with anti-inflammatory effects, but its effects in COPD are unknown. We investigated accelerated metformin therapy in severe COPD exacerbations, primarily to confirm or refute an anti-hyperglycaemic effect, and secondarily to explore its effects on inflammation and clinical outcome.

Methods

This was a multicentre, randomised, double-blind, placebo-controlled trial testing accelerated metformin therapy in non-diabetic patients, aged ≥35 years, hospitalised for COPD exacerbations. Participants were assigned in a 2:1 ratio to 1 month of metformin therapy, escalated rapidly to 2 g/day, or matched placebo. The primary end point was mean in-hospital blood glucose concentration. Secondary end points included the concentrations of fructosamine and C reactive protein (CRP), and scores on the COPD Assessment Test and Exacerbations of Chronic Pulmonary Disease Tool.

Results

52 participants (mean (±SD) age 67±9 years) were randomised (34 to metformin, 18 to placebo). All were included in the primary end point analysis. The mean blood glucose concentrations in the metformin and placebo groups were 7.1±0.9 and 8.0±3.3 mmol/L, respectively (difference −0.9 mmol/L, 95% CI −2.1 to +0.3; p=0.273). No significant between-group differences were observed on any of the secondary end points. Adverse reactions, particularly gastrointestinal effects, were more common in metformin-treated participants.

Conclusion

Metformin did not ameliorate elevations in blood glucose concentration among non-diabetic patients admitted to hospital for COPD exacerbations, and had no detectable effect on CRP or clinical outcomes.

Trial registration number

ISRCTN66148745 and NCT01247870.

COPD: the patient perspective

Chronic obstructive pulmonary disease (COPD) is a highly prevalent disease characterized by nonreversible airway obstruction. Well-characterized symptoms such as exertional dyspnea and fatigue have a negative impact on patients' quality of life (QoL) and restrict physical activity in daily life. The impact of COPD symptoms on QoL is often underestimated; for example, 36% of patients who describe their symptoms as being mild-to-moderate also admit to being too breathless to leave the house. Additionally, early morning and nighttime symptoms are a particular problem. Methods are available to allow clinicians to accurately assess COPD symptoms, including patient questionnaires. Integrated approaches to COPD management, particularly pulmonary rehabilitation, are effective strategies for addressing symptoms, improving exercise capacity and, potentially, also increasing physical activity. Inhaled bronchodilators continue to be the mainstay of drug therapy in COPD, where options can be tailored to meet patients' needs with careful selection of the inhaled medication and the device used for its delivery. Overall, an integrated approach to disease management should be considered for improving QoL and subsequent patient outcomes in COPD.

Exacerbations of COPD

Exacerbations of chronic obstructive pulmonary disease (COPD) are defined as sustained worsening of a patient’s condition beyond normal day-to-day variations that is acute in onset, and that may also require a change in medication and/or hospitalization. Exacerbations have a significant and prolonged impact on health status and outcomes, and negative effects on pulmonary function. A significant proportion of exacerbations are unreported and therefore left untreated, leading to a poorer prognosis than those treated. COPD exacerbations are heterogeneous, and various phenotypes have been proposed which differ in biologic basis, prognosis, and response to therapy. Identification of biomarkers could enable phenotype-driven approaches for the management and prevention of exacerbations. For example, several biomarkers of inflammation can help to identify exacerbations most likely to respond to oral corticosteroids and antibiotics, and patients with a frequent exacerbator phenotype, for whom preventative treatment is appropriate. Reducing the frequency of exacerbations would have a beneficial impact on patient outcomes and prognosis. Preventative strategies include modification of risk factors, treatment of comorbid conditions, the use of bronchodilator therapy with long-acting β₂-agonists or long-acting muscarinic antagonists, and inhaled corticosteroids. A better understanding of the mechanisms underlying COPD exacerbations will help to optimize use of the currently available and new interventions for preventing and treating exacerbations.

The COPD Assessment Test: What Do We Know So Far?: A Systematic Review and Meta-Analysis About Clinical Outcomes Prediction and Classification of Patients Into GOLD Stages

BACKGROUND

The COPD Assessment Test (CAT) was developed as a simple instrument to assess health status in patients with COPD. This study aimed to systematically review the determinants of the CAT score, its ability to predict clinical outcomes, and the agreement between CAT (≥ 10) and the modified Medical Research Council scale (mMRC ≥ 2) to categorize patients into the new Global Initiative for Chronic Obstructive Lung Disease classification system.

METHODS

From January 1, 2009, to June 30, 2015, databases were searched for studies using CAT in adults with COPD and in general populations aiming to detect COPD. Two investigators independently screened, selected, and extracted data by using a standardized form. Where appropriate, the results were combined in a random effects meta-analysis.

RESULTS

Of 453 studies, 17 were included, and eight were used in the meta-analysis. The models to predict the CAT score were able to explain < 50% of its variance. CAT scores can indicate risk of exacerbation, depression, acute deterioration in health status, and mortality. All studies found a different proportion of patients in each Global Initiative for Chronic Obstructive Lung Disease category using CAT ≥ 10 or mMRC ≥ 2. On average, the distribution was 13% different according to the instrument used. The κ agreement between CAT and mMRC ranged from 0.13 to 0.77.

CONCLUSIONS

CAT may be used as a complementary tool in a patient's clinical assessment to predict COPD exacerbation, health status deterioration, depression, and mortality. The interpretation of this meta-analysis does not support the use of the recommended cutoff points of ≥10 for CAT and ≥2 for mMRC as equivalents for the purpose of assessing patient symptoms.

Determinants of chronic obstructive pulmonary disease severity in the late-elderly differ from those in younger patients

BACKGROUND

Although the age range of chronic obstructive pulmonary disease (COPD) patients is broad, few studies have focused on the effects of age on disease characteristics.

METHODS

Keio University and affiliated hospitals established an observational COPD cohort. Patients were assessed using high resolution computed tomography (CT) to quantify emphysema, health status using the COPD assessment test (CAT) and the St. George's Respiratory Questionnaire (SGRQ), spirometry, echocardiogram, dual X-ray absorption of bone, biomarkers and comorbid diagnoses. We examined the characteristics of COPD patients aged 75 and over compared with patients below 75.

RESULTS

A total of 443 patients comprising 252 patients aged <75 years and 191 patients aged ≥75 years, were enrolled. Emphysematous changes on CT and prevalence of possible pulmonary hypertension were greater in late-elderly patients. The slope of the relationship between CT emphysema densitometry score and forced expiratory volume in 1 s was significantly less steep in the late-elderly than the younger patients (p = 0.002). CAT and total SGRQ scores and the frequency of long-term oxygen therapy were significantly higher in the late-elderly with moderate airflow obstruction compared to those of the younger in the same grade, although the opposite was seen in late-elderly patients with very severe airflow obstruction. Hypertension, aortic aneurysm, prostatic hypertrophy, anemia, and cataract are more prevalent in late-elderly patients.

CONCLUSIONS

Elderly COPD patients show a varied age-related pattern of disease that warrants specific attention in clinical practice above and beyond assessment of airflow limitation. Trial registration Clinical trial registered with the University Hospital Medical Information Network (UMIN000003470, April 10, 2010).

Blood eosinophils and inhaled corticosteroid/long-acting β-2 agonist efficacy in COPD

Objective

We performed a review of studies of fluticasone propionate (FP)/salmeterol (SAL) (combination inhaled corticosteroid (ICS)/long-acting β2-agonist (LABA)) in patients with COPD, which measured baseline (pretreatment) blood eosinophil levels, to test whether blood eosinophil levels ≥2% were associated with a greater reduction in exacerbation rates with ICS therapy.

Methods

Three studies of ≥1-year duration met the inclusion criteria. Moderate and severe exacerbation rates were analysed according to baseline blood eosinophil levels (<2% vs ≥2%). At baseline, 57–75% of patients had ≥2% blood eosinophils. Changes in FEV₁ and St George's Respiratory Questionnaire (SGRQ) scores were compared by eosinophil level.

Results

For patients with ≥2% eosinophils, FP/SAL was associated with significant reductions in exacerbation rates versus tiotropium (INSPIRE: n=719, rate ratio (RR)=0.75, 95% CI 0.60 to 0.92, p=0.006) and versus placebo (TRISTAN: n=1049, RR=0.63, 95% CI 0.50 to 0.79, p<0.001). No significant difference was seen in the <2% eosinophil subgroup in either study (INSPIRE: n=550, RR=1.18, 95% CI 0.92 to 1.51, p=0.186; TRISTAN: n=354, RR=0.99, 95% CI 0.67 to 1.47, p=0.957, respectively). In SCO30002 (n=373), no significant effects were observed (FP or FP/SAL vs placebo). No relationship was observed in any study between eosinophil subgroup and treatment effect on FEV₁ and SGRQ.

Discussion

Baseline blood eosinophil levels may represent an informative marker for exacerbation reduction with ICS/LABA in patients with COPD and a history of moderate/severe exacerbations.

Predictors of Mortality in Patients with COPD and Chronic Respiratory Failure: The Quality-of-Life Evaluation and Survival Study (QuESS): A Three-Year Study

Previous studies sought to identify survival or outcome predictors in patients with COPD and chronic respiratory failure, but their findings are inconsistent. We identified mortality-associated factors in a prospective study in 21 centers in 7 countries. Follow-up data were available in 221 patients on home mechanical ventilation and/or long-term oxygen therapy.

MEASUREMENTS

diagnosis, co-morbidities, medication, oxygen therapy, mechanical ventilation, pulmonary function, arterial blood gases, exercise performance were recorded. Health status was assessed using the COPD-specific SGRQ and the respiratory-failure-specific MRF26 questionnaires. Date and cause of death were recorded in those who died. Overall mortality was 19.5%. The commonest causes of death were related to the underlying respiratory diseases. At baseline, patients who subsequently died were older than survivors (p = 0.03), had a lower forced vital capacity (p = 0.03), a higher use of oxygen at rest (p = 0.003) and a worse health status (SGRQ and MRF26, both p = 0.02). Longitudinal analyses over a follow-up period of 3 years showed higher median survival times in patients with use of oxygen at rest less than 1.75 l/min and with a better health status. In contrast, an increase from baseline levels of 1 liter in O2 flow at rest, 1 unit in SGRQ or MRF26, or 1 year increase in age resulted in an increase of mortality of 68%, 2.4%, 1.3%, and 6%, respectively. In conclusion, the need for oxygen at rest, and health status assessment seems to be the strongest predictors of mortality in COPD patients with chronic respiratory failure.

The EFFECT trial: evaluating exacerbations, biomarkers, and safety outcomes with two dose levels of fluticasone propionate/formoterol in COPD

Inhaled corticosteroid/long-acting β2-agonist combination therapy is recommended in chronic obstructive pulmonary disease (COPD) patients at high risk of exacerbations. The EFFECT (Efficacy of Fluticasone propionate/FormotErol in COPD Treatment) trial is a Phase III, 52-week, randomized, double-blind study to evaluate the efficacy and safety of two doses of fluticasone propionate/formoterol compared to formoterol monotherapy in COPD patients with FEV1 ≥50% predicted and a history of exacerbations. The primary endpoint is the annualized rate of moderate and severe exacerbations. Secondary endpoints include pre-dose FEV1, EXACT-PRO (EXAcerbations of Chronic pulmonary disease Tool - Patient-Reported Outcome)-defined exacerbations, St George's Respiratory Questionnaire for COPD, COPD Assessment Test, and EXACT-Respiratory Symptoms total score. Lung-specific biomarkers (surfactant protein D and CC chemokine ligand-18) will be measured in a subset of patients to explore their relationship to other clinical indices in COPD and their predictive utility. Pneumonia will be diagnosed per criteria defined by the British Thoracic Society community acquired pneumonia guideline, primarily by radiological confirmation and, additionally, using clinical criteria when a chest radiograph cannot be obtained. Serial measurements of serum potassium, vital signs and electrocardiograms, 24-hour Holter monitoring, and 24-hour urinary cortisol measurement will be performed in a subset of patients in addition to conventional safety assessments.

Atrioventricular and ventricular-to-ventricular programming in patients with cardiac resynchronization therapy: results from ALTITUDE

PURPOSE

Cardiac resynchronization therapy (CRT) improves outcomes in patients with heart failure, yet response rates are variable. We sought to determine whether physician-specified CRT programming was associated with improved outcomes.

METHODS

Using data from the ALTITUDE remote follow-up cohort, we examined sensed atrioventricular (AV) and ventricular-to-ventricular (VV) programming and their associated outcomes in patients with de novo CRT from 2009-2010. Outcomes included arrhythmia burden, left ventricular (LV) pacing, and all-cause mortality at 4 years.

RESULTS

We identified 5709 patients with de novo CRT devices; at the time of implant, 34% (n = 1959) had entirely nominal settings programmed, 40% (n = 2294) had only AV timing adjusted, 11% (n = 604) had only VV timing adjusted, and 15% (n = 852) had both AV and VV adjusted from nominal programming. Suboptimal LV pacing (<95%) during follow-up was similar across groups; however, the proportion with atrial fibrillation (AF) burden >5% was lowest in the AV-only adjusted group (17.9%) and highest in the nominal (27.7%) and VV-only adjusted (28.3%) groups. Adjusted all-cause mortality was significantly higher among patients with non-nominal AV delay >120 vs. <120 ms (adjusted heart rate (HR) 1.28, p = 0.008) but similar when using the 180-ms cutoff (adjusted HR 1.13 for >180 vs. ≤180 ms, p = 0.4).

CONCLUSIONS

Nominal settings for de novo CRT implants are frequently altered, most commonly the AV delay. There is wide variability in reprogramming. Patients with nominal or AV-only adjustments appear to have favorable pacing and arrhythmia outcomes. Sensed AV delays less than 120 ms are associated with improved survival.

The learning curve associated with the introduction of the subcutaneous implantable defibrillator

Aims

The subcutaneous implantable cardioverter defibrillator (S-ICD) was introduced to overcome complications related to transvenous leads. Adoption of the S-ICD requires implanters to learn a new implantation technique. The aim of this study was to assess the learning curve for S-ICD implanters with respect to implant-related complications, procedure time, and inappropriate shocks (IASs).

Methods and results

In a pooled cohort from two clinical S-ICD databases, the IDE Trial and the EFFORTLESS Registry, complications, IASs at 180 days follow-up and implant procedure duration were assessed. Patients were grouped in quartiles based on experience of the implanter and Kaplan–Meier estimates of complication and IAS rates were calculated. A total of 882 patients implanted in 61 centres by 107 implanters with a median of 4 implants (IQR 1,8) were analysed. There were a total of 59 patients with complications and 48 patients with IAS. The complication rate decreased significantly from 9.8% in Quartile 1 (least experience) to 5.4% in Quartile 4 (most experience) (P = 0.02) and non-significantly for IAS from 7.9 to 4.8% (P = 0.10). Multivariable analysis demonstrated a hazard ratio of 0.78 (P = 0.045) for complications and 1.01 (P = 0.958) for IAS. Dual-zone programming increased with experience of the individual implanter (P < 0.001), which reduced IAS significantly in the multivariable model (HR 0.44, P = 0.01). Procedure time decreased from 75 to 65 min (P < 0.001). The complication rate and procedure time stabilized after Quartile 2 (>13 implants).

Conclusion

There is a short and significant learning curve associated with physicians adopting the S-ICD. Performance stabilizes after 13 implants.

Impact of cardiovascular comorbidities on COPD Assessment Test (CAT) and its responsiveness to pulmonary rehabilitation in patients with moderate to very severe COPD: protocol of the Chance study

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality. Patients with COPD are characterised by a reduced health status, which can be easily assessed by the COPD Assessment Test (CAT). Previous studies show that health status can be worsened by the presence of comorbidities. However, the impact of cardiovascular comorbidities on health status as assessed with CAT is not sufficiently investigated. Therefore, the current study has the following objectives: (1) to study the clinical, (patho)physiological and psychosocial determinants of the CAT, and impact of previously established and/or newly diagnosed cardiovascular comorbidities on health status in tertiary care patients with COPD; (2) to assess the effects of pulmonary rehabilitation on CAT scores in patients with COPD; (3) to develop reference values for the CAT in Dutch elderly patients without COPD; and (4) to validate the CAT in a broad sample of Dutch patients with COPD.

METHODS AND ANALYSIS

The COPD, Health status and Comorbidities (Chance) study is a monocentre study consisting of an observational cross-sectional part and a longitudinal part. Demographic and clinical characteristics will be assessed in primary care, secondary care and tertiary care patients with COPD, and in patients without COPD. To assess health status, the CAT, Clinical COPD Questionnaire (CCQ) and St George's Respiratory Questionnaire (SGRQ) will be used. The longitudinal part consists of a comprehensive pulmonary rehabilitation programme in 500 tertiary care patients. For the cross-sectional part of the study, 150 patients without COPD, 100 primary care patients and 100 secondary care patients will be assessed during a single home visit.

ETHICS AND DISSEMINATION

The Medical Ethical Committee of the Maastricht University Medical Centre+ (MUMC+), Maastricht, the Netherlands (METC 11-3-070), has approved this study. The study has been registered at the Dutch Trial Register (NTR 3416).