Endurance shuttle walking test: responsiveness to salmeterol in COPD

Comparative measurement properties of constant work rate cycling and the endurance shuttle walking test in COPD: the TORRACTO® clinical trial

Background:

Exercise tolerance is an important endpoint in chronic obstructive pulmonary disease (COPD) clinical trials. Little is known about the comparative measurement properties of constant work rate cycle ergometry (CWRCE) and the endurance shuttle walking test (ESWT). The objective of this sub-analysis of the TORRACTO^® study was to directly compare the endurance measurement properties of CWRCE and ESWT in patients with COPD in a multicentre, multinational setting. We predicted that both tests would be similarly reliable, but that the ESWT would be more responsive to bronchodilation than CWRCE.

Methods:

This analysis included 151 patients who performed CWRCE and ESWT at baseline and week 6 after receiving once-daily placebo, tiotropium/olodaterol (T/O) 2.5/5 μg or T/O 5/5 μg. Reproducibility was assessed by comparing their respective performance at baseline and week 6 in the placebo group. Responsiveness to bronchodilation was assessed by comparing endurance time at week 6 with T/O with baseline values and placebo. The locus of symptom limitation and end-exercise Borg scales for breathing and leg discomfort for both tests were also analysed.

Results:

The intraclass correlation coefficients for CWRCE and ESWT were 0.56 [95% confidence interval (CI) 0.37–0.71] and 0.75 (95% CI 0.63–0.84). More patients were limited by breathing discomfort during the ESWT than during CWRCE, whereas more patients were limited by leg discomfort or breathing/leg discomfort during CWRCE than the ESWT (p <0.0001). Both tests were responsive to bronchodilator treatment: there was a 19% increase in endurance time from baseline at week 6 (p = 0.0006) assessed with CWRCE, and a 20% increase in endurance time assessed with ESWT (p = 0.0013).

Conclusions:

Both exercise tests performed well in a multicentre clinical trial. Although the locus of symptom limitation differed between the two tests, both were reliable and responsive to bronchodilation. For future clinical trials, the choice of test should depend on the study requirements.

ClinicalTrials.gov identifier:

NCT01525615.

The reviews of this paper are available via the supplemental material section.

The added value of ultrasound muscle measurements in patients with COPD: An exploratory study

BACKGROUND AND AIMS

Malnutrition and sarcopenia are common nutrition (-related) disorders in patients with COPD and are associated with negative health outcomes and mortality. This study aims to correlate ultrasound measured rectus femoris size with fat-free mass and muscle function in patients with COPD.

METHODS

Patients with COPD, at the start of a pulmonary rehabilitation program, were asked to participate in this study. Rectus femoris (RF) size (thickness in cm, cross-sectional area [CSA] in cm²) was determined by ultrasound. Fat-free mass index (FFMI in kg/m²) was estimated with bioelectrical impedance analyses, using a disease-specific equation. Handgrip strength (HGS) was measured in kilograms and the five times sit to stand test (in seconds, higher scores indicating decreased strength) was performed to assess leg muscle power. The Incremental Shuttle Walk Test (ISWT, in m) was used to assess maximal exercise capacity.

RESULTS

In total, 44 patients with COPD (mean age 59.8 ± 8.6 years, 43% male, median FEV1%pred 37 [IQR = 23-52]) were included. Greater RF-CSA and thickness were associated with higher FFMI (r = 0.57, p < 0.001; r = 0.53, p = 0.003, respectively) and HGS (CSA r = 0.58, p < 0.001, thickness r = 0.48, p = 0.009). No significant correlations between RF-thickness, CSA, and leg muscle power were found (r = -0.33, p = 0.091; r = -0.35, p = 0.073, respectively). Furthermore, no correlation between RF size and maximal exercise capacity was observed (thickness r = 0.21, p = 0.297, CSA r = 0.22, p = 0.274).

CONCLUSIONS

This exploratory study shows that in patients with COPD, rectus femoris size is moderately correlated with FFMI and HGS. Future studies should focus on the role of ultrasound in evaluating nutritional status.

Effect of 12 weeks of once-daily tiotropium/olodaterol on exercise endurance during constant work-rate cycling and endurance shuttle walking in chronic obstructive pulmonary disease

Background:

The TORRACTO^® study evaluated the effects of tiotropium/olodaterol versus placebo on endurance time during constant work-rate cycling and constant speed shuttle walking in patients with chronic obstructive pulmonary disease (COPD) after 12 weeks of treatment.

Methods:

The effects of once-daily tiotropium/olodaterol (2.5/5 and 5/5 μg) on endurance time during constant work-rate cycle ergometry (CWRCE) after 6 and 12 weeks of treatment were compared with placebo in patients with COPD in a randomized, double-blind, placebo-controlled, parallel-group clinical trial. Endurance time during the endurance shuttle walk test (ESWT) after 6 and 12 weeks of treatment was also evaluated in a subset of patients.

Results:

A total of 404 patients received treatment, with 165 participating in the ESWT substudy. A statistically significant improvement in endurance time during CWRCE was observed after 12 weeks (primary endpoint) with tiotropium/olodaterol 5/5 µg [14% (p = 0.02)] but not with tiotropium/olodaterol 2.5/5 µg [9% (p = 0.14)] versus placebo. In the ESWT substudy, a trend to improvement in endurance time during ESWT after 12 weeks (key secondary endpoint) was observed with tiotropium/olodaterol 5/5 µg [21% (p = 0.055)] and tiotropium/olodaterol 2.5/5 µg [21% (p = 0.056)] versus placebo.

Conclusion:

Tiotropium/olodaterol 5/5 µg improved endurance time during cycle ergometry versus placebo, with a strong tendency to also improve walking endurance time.

[ClinicalTrials.gov identifier: NCT01525615.]

Effects of umeclidinium/vilanterol on exercise endurance in COPD: a randomised study

This multicentre, randomised, double-blind, placebo-controlled, two-period crossover study assessed the effect of umeclidinium/vilanterol (UMEC/VI) on exercise capacity in patients with chronic obstructive pulmonary disease (COPD) using the endurance shuttle walk test (ESWT). Patients were randomised 1:1 to one of two treatment sequences: 1) UMEC/VI 62.5/25 µg followed by placebo or 2) placebo followed by UMEC/VI 62.5/25 µg. Each treatment was taken once daily for 12 weeks. The primary end-point was 3-h post-dose exercise endurance time (EET) at week 12. Secondary end-points included trough forced expiratory volume in 1 s (FEV₁) and 3-h post-dose functional residual capacity (FRC), both at week 12. COPD Assessment Test (CAT) score at week 12 was also assessed. UMEC/VI treatment did not result in a statistically significant improvement in EET change from baseline at week 12 versus placebo (p=0.790). However, improvements were observed in trough FEV₁ (206 mL, 95% CI 167-246), 3-h post-dose FRC (-346 mL, 95% CI -487 to -204) and CAT score (-1.07 units, 95% CI -2.09 to -0.05) versus placebo at week 12. UMEC/VI did not result in improvements in EET at week 12 versus placebo, despite improvements in measures of lung function, hyperinflation and health status.

Predicting treatable traits for long-acting bronchodilators in patients with stable COPD

Purpose

There is currently no measure to predict a treatability of long-acting β-2 agonist (LABA) or long-acting muscarinic antagonist (LAMA) in patients with chronic obstructive pulmonary disease (COPD). We aimed to build prediction models for the treatment response to these bronchodilators, in order to determine the most responsive medication for patients with COPD.

Methods

We performed a prospective open-label crossover study, in which each long-acting bronchodilator was given in a random order to 65 patients with stable COPD for 4 weeks, with a 4-week washout period in between. We analyzed 14 baseline clinical traits, expression profiles of 31,426 gene transcripts, and damaged-gene scores of 6,464 genes acquired from leukocytes. The gene expression profiles were measured by RNA microarray and the damaged-gene scores were obtained after DNA exome sequencing. Linear regression analyses were performed to build prediction models after using factor and correlation analyses.

Results

Using a prediction model for a LABA, traits found associated with the treatment response were post-bronchodilator forced expiratory volume in 1 second, bronchodilator reversibility (BDR) to salbutamol, expression of three genes (CLN8, PCSK5, and SKP2), and damage scores of four genes (EPG5, FNBP4, SCN10A, and SPTBN5) (R²=0.512, p<0.001). Traits associated with the treatment response to a LAMA were COPD assessment test score, BDR, expression of four genes (C1orf115, KIAA1618, PRKX, and RHOQ) and damage scores of three genes (FBN3, FDFT1, and ZBED6) (R²=0.575, p<0.001). The prediction models consisting only of clinical traits appeared too weak to predict the treatment response, with R²=0.231 for the LABA model and R²=0.121 for the LAMA model.

Conclusion

Adding the expressions of genes and damaged-gene scores to the clinical traits may improve the predictability of treatment response to long-acting bronchodilators.

Three-minute constant rate step test for detecting exertional dyspnea relief after bronchodilation in COPD

Background

The aim of this study was to evaluate the responsiveness of the 3-minute constant rate step test (3-MST) to detect the relief of exertional dyspnea (respiratory discomfort) after acute bronchodilation in COPD patients.

Patients and methods

A total of 40 patients with moderate-to-severe COPD (mean forced expiratory volume in 1 second: 45.7 (±14.7), % predicted) performed four 3-MSTs at randomly assigned stepping rates of 14, 16, 20 and 24 steps/min after inhalation of nebulized ipratropium bromide (500 µg)/salbutamol (2.5 mg) and saline placebo, which were randomized to order. Patients rated their intensity of perceived dyspnea at the end of each 3-MST using Borg 0–10 category ratio scale.

Results

A total of 37 (92.5%), 36 (90%), 34 (85%) and 27 (67.5%) patients completed all 3 minutes of exercise at 14, 16, 20 and 24 steps/min under both treatment conditions, respectively. Compared with placebo, ipratropium bromide/salbutamol significantly decreased dyspnea at the end of the third minute of exercise at 14 steps/min (by 0.6±1.0 Borg 0–10 scale units, P<0.01) and 16 steps/min (by 0.7±1.3 Borg 0–10 scale units, P<0.01); however, no statically significant differences were observed between treatments at 20 and 24 steps/min (both P>0.05).

Conclusion

The 3-MST, when performed at 14 and 16 steps/min, was responsive to detect the relief of exertional dyspnea after acute bronchodilation in patients with moderate-to-severe COPD.

Functional Status Assessment of Patients With COPD: A Systematic Review of Performance-Based Measures and Patient-Reported Measures

Presently, there is no recommendation on how to assess functional status of chronic obstructive pulmonary disease (COPD) patients. This study aimed to summarize and systematically evaluate these measures.Studies on measures of COPD patients' functional status published before the end of January 2015 were included using a search filters in PubMed and Web of Science, screening reference lists of all included studies, and cross-checking against some relevant reviews. After title, abstract, and main text screening, the remaining was appraised using the Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) 4-point checklist. All measures from these studies were rated according to best-evidence synthesis and the best-rated measures were selected.A total of 6447 records were found and 102 studies were reviewed, suggesting 44 performance-based measures and 14 patient-reported measures. The majority of the studies focused on internal consistency, reliability, and hypothesis testing, but only 21% of them employed good or excellent methodology. Their common weaknesses include lack of checks for unidimensionality, inadequate sample sizes, no prior hypotheses, and improper methods. On average, patient-reported measures perform better than performance-based measures. The best-rated patient-reported measures are functional performance inventory (FPI), functional performance inventory short form (FPI-SF), living with COPD questionnaire (LCOPD), COPD activity rating scale (CARS), University of Cincinnati dyspnea questionnaire (UCDQ), shortness of breath with daily activities (SOBDA), and short-form pulmonary functional status scale (PFSS-11), and the best-rated performance-based measures are exercise testing: 6-minute walk test (6MWT), endurance treadmill test, and usual 4-meter gait speed (usual 4MGS).Further research is needed to evaluate the reliability and validity of performance-based measures since present studies failed to provide convincing evidence. FPI, FPI-SF, LCOPD, CARS, UCDQ, SOBDA, PFSS-11, 6MWT, endurance treadmill test, and usual 4MGS performed well and are preferable to assess functional status of COPD patients.

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.

Repeatability of the endurance shuttle walk test in people with chronic obstructive pulmonary disease

INTRODUCTION

Walking tests, including the endurance shuttle walk test (ESWT), have been used to assess functional capacity in people with chronic obstructive pulmonary disease (COPD). Learning effects through repeated practice have been reported for some field walking tests. However, the repeatability of ESWT at various time points, i.e. within the same day, within the week and one week apart, has not been examined.

OBJECTIVES

This study aimed to evaluate the repeatability of ESWT overtime to determine whether or not a learning effect existed.

METHODS

Twenty-two participants diagnosed with COPD [age 71 ± 6 years; FEV₁ % predicted 54 ± 24%] were recruited. Participants performed two incremental shuttle walk tests to determine the walking speed for the ESWT and a practice ESWT (E_p ) to determine whether the ESWT level was appropriate. ESWT 1(E₁ ) and ESWT 2(E₂ ) were performed on the same day, 30 min apart; ESWT 3(E₃ ) was performed within a week from E₂ ; ESWT 4(E₄ ) was performed one week after E₃ . Duration walked in each ESWT was recorded. The repeatability of the four ESWTs was analyzed using repeated measures analysis of variance.

RESULTS

The mean durations of E₁ to E₄ were 368 ± 203 s, 371 ± 182 s, 386 ± 213 s and 367 ± 223 s, respectively, with no time effect (F=0.18, P=0.79).

CONCLUSION

There was no evidence of learning effect when ESWT was repeated within one day, within one week and one week apart, once the appropriate baseline level was established, showing that ESWT is repeatable in people with moderate COPD.

Effects of a combination of umeclidinium/vilanterol on exercise endurance in patients with chronic obstructive pulmonary disease: two randomized, double-blind clinical trials

OBJECTIVE

Exercise intolerance is a hallmark of chronic obstructive pulmonary disease (COPD).

METHODS

Patients with COPD were randomized in two multicentre, double-blind, incomplete block crossover studies. Patients received two of six treatments in sequence (12 weeks each): placebo, umeclidinium (UMEC)/vilanterol (VI) (125/25 mcg or 62.5/25 mcg), VI (25 mcg) or UMEC (62.5 mcg or 125 mcg). Exercise endurance time (EET) and trough forced expiratory volume in 1 second (FEV1) (Week 12) were co-primary endpoints. Safety was monitored throughout.

RESULTS

Both studies showed similar 3-hour post-dose EET improvements from baseline for UMEC/VI (Week 12). Significant EET improvements were observed with both UMEC/VI doses versus placebo at Week 12 in Study 418 (UMEC/VI 125/25 mcg: 65.8 s; p = 0.005; UMEC/VI 62.5/25 mcg: 69.4 s; p = 0.003), but not in Study 417, where a placebo effect was evident. Post hoc integrated data analysis showed significant but smaller EET improvements for both UMEC/VI doses versus placebo at Week 12 (UMEC/VI 125/25 mcg: 47.5 s; p = 0.002; UMEC/VI 62.5/25 mcg: 43.7 s; p = 0.001). Both studies showed trough FEV1 improvements at Week 12 for both UMEC/VI doses. The incidence of adverse events was similar between treatment groups within each study.

CONCLUSIONS

UMEC/VI improved lung function and EET.

Does Improving Exercise Capacity and Daily Activity Represent the Holistic Perspective of a New COPD Approach?

In COPD patients a reduced daily activity has been well documented, resulting from both respiratory and non-respiratory manifestations of the disease. An evaluation by multisensory armband has confirmed that daily physical activity is mainly associated with dynamic hyperinflation, regardless of COPD severity. This aspect is crucial, since exercise capacity is closely correlated to life expectancy. Notwithstanding the causal key role of lung impairment in the patient's symptoms, some authors have suggested that other factors, such as systemic inflammation and co-morbidities, have an important role, particularly as mortality risk factors. Many studies suggest the efficacy of bronchodilators and rehabilitation in improving exercise capacity, and, speaking in terms of daily life, in increasing the number of days in which patients are able to perform their usual activities. On this evidence, the first aim in the management of COPD should be to improve exercise capacity and daily activity since these outcomes have direct effects on patients' quality of life, co-morbidities (heart and metabolic diseases), and prognosis. Thus, improving physical activity represents a modern approach aimed at dealing with both pulmonary and systemic manifestations of the disease. It is however worth of notice to remember that in patients affected by COPD the relationship between the improvement of "potential" exercise capacity and daily physical activity has been found to be only moderate to weak. Obtaining a significant behavior modification with regard to daily physical activity, together with the optimization of therapy thus represents currently the true challenge.

Changes in the endurance shuttle walk test in COPD patients with chronic respiratory failure after pulmonary rehabilitation: the minimal important difference obtained with anchor- and distribution-based method

Background

Although the endurance shuttle walk test (ESWT) has proven to be responsive to change in exercise capacity after pulmonary rehabilitation (PR) for COPD, the minimally important difference (MID) has not yet been established. We aimed to establish the MID of the ESWT in patients with severe COPD and chronic hypercapnic respiratory failure following PR.

Methods

Data were derived from a randomized controlled trial, investigating the value of noninvasive positive pressure ventilation added to PR. Fifty-five patients with stable COPD, GOLD stage IV, with chronic respiratory failure were included (mean (SD) FEV₁ 31.1 (12.0) % pred, age 62 (9) y). MID estimates of the ESWT in seconds, percentage and meters change were calculated with anchor based and distribution based methods. Six minute walking distance (6MWD), peak work rate on bicycle ergometry (Wpeak) and Chronic Respiratory Questionnaire (CRQ) were used as anchors and Cohen’s effect size was used as distribution based method.

Results

The estimated MID of the ESWT with the different anchors ranged from 186–199 s, 76–82% and 154–164 m. Using the distribution based method the MID was 144 s, 61% and 137 m.

Conclusions

Estimates of the MID for the ESWT after PR showed only small differences using different anchors in patients with COPD and chronic respiratory failure. Therefore we recommend using a range of 186–199 s, 76–82% or 154–164 m as MID of the ESWT in COPD patients with chronic respiratory failure. Further research in larger populations should elucidate whether this cut-off value is also valid in other COPD populations and with other interventions.

Trial registration

ClinicalTrials.Gov (ID NCT00135538).

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-015-0182-x) contains supplementary material, which is available to authorized users.

An official European Respiratory Society/American Thoracic Society technical standard: field walking tests in chronic respiratory disease

Field walking tests are commonly employed to evaluate exercise capacity, assess prognosis and evaluate treatment response in chronic respiratory diseases. In recent years, there has been a wealth of new literature pertinent to the conduct of the 6-min walk test (6MWT), and a growing evidence base describing the incremental and endurance shuttle walk tests (ISWT and ESWT, respectively). The aim of this document is to describe the standard operating procedures for the 6MWT, ISWT and ESWT, which can be consistently employed by clinicians and researchers. The Technical Standard was developed by a multidisciplinary and international group of clinicians and researchers with expertise in the application of field walking tests. The procedures are underpinned by a concurrent systematic review of literature relevant to measurement properties and test conduct in adults with chronic respiratory disease. Current data confirm that the 6MWT, ISWT and ESWT are valid, reliable and responsive to change with some interventions. However, results are sensitive to small changes in methodology. It is important that two tests are conducted for the 6MWT and ISWT. This Technical Standard for field walking tests reflects current evidence regarding procedures that should be used to achieve robust results.

An official systematic review of the European Respiratory Society/American Thoracic Society: measurement properties of field walking tests in chronic respiratory disease

This systematic review examined the measurement properties of the 6-min walk test (6MWT), incremental shuttle walk test (ISWT) and endurance shuttle walk test (ESWT) in adults with chronic respiratory disease.

Studies that report the evaluation or use of the 6MWT, ISWT or ESWT were included. We searched electronic databases for studies published between January 2000 and September 2013.

The 6-min walking distance (6MWD) is a reliable measure (intra-class correlation coefficients ranged from 0.82 to 0.99 in seven studies). There is a learning effect, with greater distance walked on the second test (pooled mean improvement of 26 m in 13 studies). Reliability was similar for ISWT and ESWT, with a learning effect also evident for ISWT (pooled mean improvement of 20 m in six studies). The 6MWD correlates more strongly with peak work capacity (r=0.59–0.93) and physical activity (r=0.40–0.85) than with respiratory function (r=0.10–0.59). Methodological factors affecting 6MWD include track length, encouragement, supplemental oxygen and walking aids. Supplemental oxygen also affects ISWT and ESWT performance. Responsiveness was moderate to high for all tests, with greater responsiveness to interventions that included exercise training.

The findings of this review demonstrate that the 6MWT, ISWT and ESWT are robust tests of functional exercise capacity in adults with chronic respiratory disease.

Saving Time for Patients with Moderate to Severe COPD: Endurance Test Speed Set Using Usual and Fast Walk Speeds

Background: For assessing the effects of interventions on exercise tolerance, the tolerable duration (t_limit) of a high-intensity constant-speed endurance test is recommended. The test intensity is determined by the test speed (s_test) which should be individualized to target a t_limit of 3 to 15 minutes. We determined the accuracy of setting the s_test to achieve a targeted t_limit of 3 to 15 minutes using the participant's easily measured and non-fatiguing usual (s_usual) and fast (s_fast) walk speeds. Methods: Participants with COPD were asked to walk at their usual and fast walk speeds to establish their s_usual and s_fast. This required that they walk for less than 1 minute. The individualized s_test was calculated from a previously developed equation (0.57 x [s_fast - s_usual]) + s_usual. Participants then completed a constant-speed endurance test, walking at this calculated s_test to intolerance, to determine if the resultant t_limit occurred within 3 to 15 minutes. Results: Twenty-nine participants (forced expiratory volume in 1 second [FEV₁] standard deviation [SD ]=43 [25] %predicted; FEV₁ to forced vital capacity [FVC]ratio= 41 [13]%; s_usual = 57.3 [10.4] meters per minute (m·min^-1 ); s_fast = 71.7 [10.7] m·min^-1) completed the study. During testing, 24 (83%) participants used supplemental oxygen and 16 (55%) used a walking aid. The derived s_test was 65.6 [10.3] m·min^-1 with the observed t_limit of 6.0 [5.0] minute. Twenty-four of 29 (83 %) endurance tests were within 3 to 15 minutes. Conclusion: Using the usual and fast walk speeds provides a simple, quick, inexpensive method for clinicians to set an acceptable endurance walk speed.

Prospective validation of the endurance shuttle walking test in the context of bronchodilation in COPD

This study focused on repeatability data and minimal important difference (MID) estimates of the endurance shuttle walking test (ESWT). 255 chronic obstructive pulmonary disease patients (forced expiratory volume in 1 s 54.7±13.2% predicted) completed four ESWTs at different times during the 8-week study: two under baseline conditions with tiotropium (1 week apart), one after a single dose and one after 4 weeks of either fluticasone propionate/salmeterol combination or placebo in addition to tiotropium. 97 patients performed all the tests with a portable metabolic system. Reproducibility of test performance and cardiorespiratory response was investigated with the data obtained on the first two ESWTs. The mean differences between the first two ESWT performances (-6.7±72.2 s and -7.3±113.1 m for endurance time and walking distance, respectively) were not statistically significant. The between-test end-exercise and isotime values for each cardiorespiratory parameter were not significantly different from each other. With the exception of arterial oxygen saturation by pulse oximetry, the repeatability of cardiorespiratory adaptations to ESWT was also confirmed with strong Pearson and intraclass correlation coefficients. Finally, changes of 56-61 s and 70-82 m in endurance time and distance walked, respectively, were perceived by patients. This study provides methodological information supporting the reliability of the ESWT and suggests MID estimates for this test.

Once-daily indacaterol 75 μg in moderate- to-severe COPD: results of a Phase IV study assessing time until patients' perceived onset of effect

Background

Indacaterol 75 μg once daily is a long-acting β₂ agonist approved for maintenance bronchodilator treatment in patients with chronic obstructive pulmonary disease (COPD). The purpose of this study was to evaluate patients’ perception of onset of effect with a single dose.

Methods

In this double-blind, crossover, Phase IV study, 40 patients were randomized to receive a single dose of indacaterol 75 μg or placebo via a dry powder inhaler device. The primary variable was time until patient’s perception of onset of effect, using a simple self-administered (nonvalidated) questionnaire that patients answered at nine protocol-specified time points. Exploratory variables included change in forced expiratory volume in 1 second (FEV₁) and change in percent predicted FEV₁ from predose to postdose (determined 60–75 minutes postdose).

Results

The least-squares mean time to patient’s perception of onset of effect was 25.4 minutes and 23.9 minutes for indacaterol and placebo, respectively. There was no significant effect for treatment, period, or sequence on the time to patient’s perception. In addition, no statistically significant differences between treatments were observed for patient’s global satisfaction with onset of effect and global expectation of treatment adherence. For the exploratory variable change in FEV₁ from predose to postdose, indacaterol showed superiority over placebo with a clinically relevant least-squares mean treatment difference of 0.12 L (P<0.0001). There was little or no association between patient’s perception of time to onset of effect and change in FEV₁, or change in percent predicted FEV₁. Both treatments were well tolerated.

Conclusion

A single dose of indacaterol 75 μg did not separate from placebo in terms of patient perception of onset, although there was an improvement in FEV₁ for indacaterol compared with placebo. Development and use of a validated questionnaire may be needed to address the inconsistency in evaluating this patient-related outcome.

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.

An official American Thoracic Society/European Respiratory Society statement: key concepts and advances in pulmonary rehabilitation

BACKGROUND

Pulmonary rehabilitation is recognized as a core component of the management of individuals with chronic respiratory disease. Since the 2006 American Thoracic Society (ATS)/European Respiratory Society (ERS) Statement on Pulmonary Rehabilitation, there has been considerable growth in our knowledge of its efficacy and scope.

PURPOSE

The purpose of this Statement is to update the 2006 document, including a new definition of pulmonary rehabilitation and highlighting key concepts and major advances in the field.

METHODS

A multidisciplinary committee of experts representing the ATS Pulmonary Rehabilitation Assembly and the ERS Scientific Group 01.02, "Rehabilitation and Chronic Care," determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant clinical and scientific expertise. The final content of this Statement was agreed on by all members.

RESULTS

An updated definition of pulmonary rehabilitation is proposed. New data are presented on the science and application of pulmonary rehabilitation, including its effectiveness in acutely ill individuals with chronic obstructive pulmonary disease, and in individuals with other chronic respiratory diseases. The important role of pulmonary rehabilitation in chronic disease management is highlighted. In addition, the role of health behavior change in optimizing and maintaining benefits is discussed.

CONCLUSIONS

The considerable growth in the science and application of pulmonary rehabilitation since 2006 adds further support for its efficacy in a wide range of individuals with chronic respiratory disease.

The use of a home exercise program based on a computer system in patients with chronic obstructive pulmonary disease

PURPOSE

To test the effectiveness of a home exercise program based on a user-friendly, computer system, the Nintendo Wii Fit.

METHODS

In this longitudinal study, 25 clinically stable patients with chronic obstructive pulmonary disease began a 6-week nonintervention (baseline) period followed by 12 weeks of Wii exercise training at home. Patients were instructed to exercise 5 or more days per week. Exercise capacity, health status, and dyspnea were evaluated after home exercise training.

RESULTS

Evaluable data were available in 20 patients after home exercise training; their force expiratory volume in 1 second was 45 ± 16%. Following 12 weeks of Wii exercise training, the Endurance Shuttle Walk Test increased by 131 ± 183 seconds over the baseline determination (P = .005). Significant improvements were also noted in arm-lift and sit-to-stand repetitions, the total score, and the emotion dimension of the Chronic Respiratory Questionnaire. Men had significantly greater increases in the Endurance Shuttle Walk Test than women, although their self-reported exercise durations were similar. There were no significant adverse outcomes.

CONCLUSION

This study suggests that 12 weeks of regular, home exercise based on an interactive entertainment computer system can lead to positive short-term outcomes.

Excitation-induced exchange of Na+, K+, and Cl- in rat EDL muscle in vitro and in vivo: physiology and pathophysiology

In skeletal muscle, excitation leads to increased [Na(+)](i), loss of K(+), increased [K(+)](o), depolarization, and Cl(-) influx. This study quantifies these changes in rat extensor digitorum longus (EDL) muscles in vitro and in vivo using flame photometric determination of Na(+) and K(+) and (36)Cl as a tracer for Cl(-). In vitro, 5-Hz stimulation for 300 s increased intracellular Na(+) content by 4.6 ± 1.2 µmol/g wet wt (P < 0.002) and decreased intracellular K(+) content by 5.5 ± 2.3 µmol/g wet wt (P < 0.03). This would increase [K(+)](o) by 28 ± 12 mM, sufficient to cause severe loss of excitability as the result of inactivation of Na(+) channels. In rat EDL, in vivo stimulation at 5 Hz for 300 s or 60 Hz for 60 s induced significant loss of K(+) (P < 0.01), sufficient to increase [K(+)](o) by 71 ± 22 mM and 73 ± 15 mM, respectively. In spite of this, excitability may be maintained by the rapid and marked stimulation of the electrogenic Na(+),K(+) pumps already documented. This may require full utilization of the transport capacity of Na(+),K(+) pumps, which then becomes a limiting factor for physical performance. In buffer containing (36)Cl, depolarization induced by increasing [K(+)](o) to 40-80 mM augmented intracellular (36)Cl by 120-399% (P < 0.001). Stimulation for 120-300 s at 5-20 Hz increased intracellular (36)Cl by 100-188% (P < 0.001). In rats, Cl(-) transport in vivo was examined by injecting (36)Cl, where electrical stimulation at 5 Hz for 300 s or 60 Hz for 60 s increased (36)Cl uptake by 81% (P < 0.001) and 84% (P < 0.001), respectively, indicating excitation-induced depolarization. Cl(-) influx favors repolarization, improving K(+) clearance and maintenance of excitability. In conclusion, excitation-induced fluxes of Na(+), K(+), and Cl(-) can be quantified in vivo, providing new evidence that in working muscles, extracellular accumulation of K(+) is considerably higher than previously observed and the resulting depression of membrane excitability may be a major cause of muscle fatigue.

Exercise and COPD: therapeutic responses, disease-related outcomes, and activity-promotion strategies

Chronic obstructive pulmonary disease (COPD) reduces patients' exercise capacities and their abilities to perform daily physical activities, thereby increasing morbidity and mortality rates. The cycle of dyspnea, deconditioning, and declining physical activity not only accelerates the progression of COPD but also increases the risk for developing or aggravating metabolic and cardiovascular diseases. Cardiovascular and metabolic comorbidities also limit physical function, and their disabling effects in combination with COPD may be greater than the effects of each disease alone. The impact of COPD and its treatment on the ability to exercise, and the degree of physical activity in daily life, can be measured by field-based tests (eg, the 6-minute walk test or incremental and endurance shuttle-walk test), laboratory-based tests (eg, incremental or constant work-rate treadmill and cycle-ergometer tests), and physical activity assessments (eg, questionnaires and accelerometers). Walking tests increase oxygen consumption and desaturation in patients with COPD more than cycling tests with similar work-rate profiles and may more closely resemble patients' normal activities. Despite the questionable relevance of exercise testing to patients' daily functionality, exercise parameters remain important predictors of survival in patients with COPD. Treatment of COPD (pharmacotherapy, pulmonary rehabilitation, or both) can increase exercise capacity and physical activity in daily life, which potentially slows the decline of lung function, reduces the frequencies of exacerbations and hospitalizations, decreases mortality, slows the progression of comorbidities, improves health-related quality of life, and increases the activity reserve for routine function. This article examines the interactions of reduced physical activity and decreased exercise capacity with the progression of COPD, comorbidities, and mortality. The article also describes the available exercise tests for patients with COPD and reviews the evidence indicating that treating COPD improves exercise capacity. Notably, it appears that even mild COPD reduces exercise capacity and daily physical activity, indicating the need for early intervention.

Responsiveness of Various Exercise-Testing Protocols to Therapeutic Interventions in COPD

Exercise intolerance is a key element in the pathophysiology and course of Chronic Obstructive Pulmonary Disease (COPD). As such, evaluating exercise tolerance has become an important part of the management of COPD. A wide variety of exercise-testing protocols is currently available, each protocol having its own strengths and weaknesses relative to their discriminative, methodological, and evaluative characteristics. This paper aims to review the responsiveness of several exercise-testing protocols used to evaluate the efficacy of pharmacological and nonpharmacological interventions to improve exercise tolerance in COPD. This will be done taking into account the minimally important difference, an important concept in the interpretation of the findings about responsiveness of exercise testing protocols. Among the currently available exercise-testing protocols (incremental, constant work rate, or self-paced), constant work rate exercise tests (cycle endurance test and endurance shuttle walking test) emerge as the most responsive ones for detecting and quantifying changes in exercise capacity after an intervention in COPD.

Modifying the course of chronic obstructive pulmonary disease: looking beyond the FEV1

COPD is defined by airflow limitation that is not fully reversible and is usually progressive. Thus, airflow obstruction (measured as FEV(1)) has traditionally been used as the benchmark defining disease modification with therapy. However, COPD exacerbations and extrapulmonary effects are common and burdensome and generally become more prominent as the disease progresses. Therefore, disease progression should be broader than FEV(1) alone. Interventions that reduce the frequency or severity of exacerbations or ameliorate extrapulmonary effects should also be considered disease modifiers. A narrow focus on FEV(1) will fail to capture all the beneficial effects of therapy on disease modification. Although smoking cessation has been unequivocally demonstrated to slow the rate of FEV(1) decline, inhaled corticosteroid-long-acting bronchodilator therapy may also have modest effects according to post hoc analysis. Maintenance pharmacotherapy with inhaled long-acting anti-muscarinic or β-adrenergic agents or combined β-adrenergic--inhaled corticosteroid reduces symptoms, improves lung function, reduces the frequency of exacerbations, and improves exercise capacity and HRQL. Pulmonary rehabilitation reduces symptom burden, increases exercise capacity, improves HRQL, and reduces health care utilization, probably through reducing the severity of exacerbations. Smoking cessation, lung volume reduction surgery, inhaled maintenance pharmacotherapy, and pulmonary rehabilitation administered in the post-exacerbation period may reduce mortality in COPD. These improvements over multiple outcome areas and over relatively long durations suggest that disease modification is indeed possible with existing therapies for COPD. Therefore, therapeutic nihilism in COPD is no longer warranted.

Once-daily NVA237 improves exercise tolerance from the first dose in patients with COPD: the GLOW3 trial

Introduction

Exercise limitation, dynamic hyperinflation, and exertional dyspnea are key features of symptomatic chronic obstructive pulmonary disease (COPD). We assessed the effects of glycopyrronium bromide (NVA237), a once-daily, long-acting muscarinic antagonist, on exercise tolerance in patients with moderate to severe COPD.

Methods

Patients were randomized to a cross-over design of once-daily NVA237 50 μg or placebo for 3 weeks, with a 14-day washout. Exercise endurance, inspiratory capacity (IC) during exercise, IC and expiratory volumes from spirometry, plethysmographic lung volumes, leg discomfort and dyspnea under exercise (Borg scales), and transition dyspnea index were measured on Days 1 and 21 of treatment. The primary endpoint was endurance time during a submaximal constant-load cycle ergometry test on Day 21.

Results

A total of 108 patients were randomized to different treatment groups (mean age, 60.5 years; mean post-bronchodilator, forced expiratory volume in 1 second [FEV₁] 57.1% predicted). Ninety-five patients completed the study. On Day 21, a 21% difference in endurance time was observed between patients treated with NVA237 and those treated with placebo (P < 0.001); the effect was also significant from Day 1, with an increase of 10%. Dynamic IC at exercise isotime and trough FEV₁ showed significant and clinically relevant improvements from Day 1 of treatment that were maintained throughout the study. This was accompanied by inverse decreases in residual volume and functional residual capacity. NVA237 was superior to placebo (P < 0.05) in decreasing leg discomfort (Borg CR10 scale) on Day 21 and exertional dyspnea on Days 1 and 21 (transition dyspnea index and Borg CR10 scale at isotime). The safety profile of NVA237 was similar to that of the placebo.

Conclusion

NVA237 50 μg once daily produced immediate and significant improvement in exercise tolerance from Day 1. This was accompanied by sustained reductions in lung hyperinflation (indicated by sustained and significant improvements in IC at isotime), and meaningful improvements in trough FEV₁ and dyspnea. Improvements in exercise endurance increased over time, suggesting that mechanisms beyond improved lung function may be involved in enhanced exercise tolerance. (ClinicalTrials.gov Identifier: NCT01154127).

Role of exercise in testing and in therapy of COPD

The stair-climbing test, 6MWT, and shuttle test are exercise tests that requires less technical support than the CPET and are more available to any physician. The 6MWT is the simplest and most likely to be cost effective, as it provides useful information regarding prognosis, ADLs, and health care use at a very low cost. In addition, the 6MWT can be used to evaluate response to several interventions, including physical rehabilitation, medications, lung volume reduction interventions, and transplantation. The 6MWT has also been useful in and has become an integral part of the evaluation and response to treatment in other medical conditions, including congestive heart failure, pulmonary hypertension, and pulmonary fibrosis. The stair-climbing test seems to be most useful for preoperative evaluations when a CPET is not available. We have also used it on patients unable to perform a good CPET because of lack of familiarity with bicycle pedaling. The shuttle walk test may be used to better determine a maximal exercise capacity when a CPET is not available and to measure the effects of pulmonary rehabilitation in patients unfamiliar with a CPET. The role of exercise as a therapeutic tool is central to the concept of pulmonary rehabilitation. Exercise training improves not only functional dyspnea and health-related quality of life, but also has been shown to decrease health care resource use. As part of a comprehensive pulmonary rehabilitation initiated after a hospitalization for exacerbation, it has been shown to decrease readmission rates.

Detecting improvements in dyspnea in COPD using a three-minute constant rate shuttle walking protocol

RATIONALE

We examined the responsiveness of a 3-minute constant rate shuttle walking protocol to detect improvements in exertional dyspnea following acute bronchodilation in COPD. Our hypothesis was that the 3-minute constant rate shuttle walking protocol would be able to adequately put forth improvements in exertional dyspnea following acute bronchodilation in this population.

METHODS

Using a placebo controlled, double-blind cross-over design, 39 patients with moderate to severe COPD performed a 3-min constant rate shuttle walking test during which they were asked to walk on a flat corridor at a speed that was externally imposed by an audio signal. During the test, dyspnea was graded using the 10-point modified Borg scale. The test was performed twice, following the administration of saline placebo or of 500 μg nebulized ipratropium bromide.

RESULTS

Improvements of respiratory pattern (respiratory rate and tidal volume) and statistically and clinically significant reductions in Borg dyspnea scores (∆ dyspnea score = 1.0 ± 0.2, p < 0.01) were seen during the 3-min shuttle walking protocol with ipratropium bromide compared to placebo.

CONCLUSION

This 3-minute shuttle walking protocol adequately detected dyspnea and breathing pattern improvements following acute bronchodilation in COPD.

Effects of β₂-agonists on force during and following anoxia in rat extensor digitorum longus muscle

Electrical stimulation of isolated muscles may lead to membrane depolarization, gain of Na(+), loss of K(+) and fatigue. These effects can be counteracted with β(2)-agonists possibly via activation of the Na(+)-K(+) pumps. Anoxia induces loss of force; however, it is not known whether β(2)-agonists affect force and ion homeostasis in anoxic muscles. In the present study isolated rat extensor digitorum longus (EDL) muscles exposed to anoxia showed a considerable loss of force, which was markedly reduced by the β(2)-agonists salbutamol (10(-6) M) and terbutaline (10(-6) M). Intermittent stimulation (15-30 min) clearly increased loss of force during anoxia and reduced force recovery during reoxygenation. The β(2)-agonists salbutamol (10(-7)-10(-5) M) and salmeterol (10(-6) M) improved force development during anoxia (25%) and force recovery during reoxygenation (55-262%). The effects of salbutamol on force recovery were prevented by blocking the Na(+)-K(+) pumps with ouabain or by blocking glycolysis with 2-deoxyglucose. Dibutyryl cAMP (1 mM) or theophylline (1 mM) also improved force recovery remarkably. In anoxic muscles, salbutamol decreased intracellular Na(+) and increased (86)Rb uptake and K(+) content, indicating stimulation of the Na(+)-K(+) pumps. In fatigued muscles salbutamol induced recovery of excitability. Thus β(2)-agonists reduce the anoxia-induced loss of force, leading to partial force recovery. These data strongly suggest that this effect is mediated by cAMP stimulation of the Na(+)-K(+) pumps and that it is not related to recovery of energy status (PCr, ATP, lactate).

Neuromodulatory effect of endogenous opioids on the intensity and unpleasantness of breathlessness during resistive load breathing in COPD

BACKGROUND

Endogenous opioids are naturally occurring peptides released by the brain in response to noxious stimuli. Although these naturally occurring peptides modulate pain, it is unknown whether endogenous opioids affect the perception of breathlessness associated with a specific respiratory challenge. The hypothesis is that intravenous administration of naloxone, used to block opioid signaling and inhibit neural pathways, will increase ratings of breathlessness during resistive load breathing (RLB) in patients with chronic obstructive pulmonary disease (COPD).

METHODS

Fourteen patients with COPD (age, 64 ± 9 years) inspired through resistances during practice sessions to identify an individualized target load that caused ratings of intensity and/or unpleasantness of breathlessness ≥ 50 mm on a 100 mm visual analog scale. At two intervention visits, serum beta-endorphins were measured, naloxone (10 mg/25 ml) or normal saline (25 ml) was administered intravenously, and patients rated the two dimensions of breathlessness each minute during RLB.

RESULTS

Patient ratings of intensity (p = 0.0004) and unpleasantness (p = 0.024) of breathlessness were higher with naloxone compared with normal saline. Eleven patients (79%) reported that it was easier to breathe during RLB with normal saline (p = 0.025). RLB led to significant increases in serum beta-endorphin immunoreactivity and decreases in inspiratory capacity. There were no significant differences in physiological responses between interventions.

CONCLUSIONS

Endogenous opioids modulate the intensity and the unpleasantness of breathlessness in patients with COPD. Differences in breathlessness ratings between interventions were clinically relevant based on the patients' global assessment.

Physiological correlates of endurance time variability during constant-workrate cycling exercise in patients with COPD

Rationale

The endurance time (T_end) during constant-workrate cycling exercise (CET) is highly variable in COPD. We investigated pulmonary and physiological variables that may contribute to these variations in T_end.

Methods

Ninety-two patients with COPD completed a CET performed at 80% of peak workrate capacity (W_peak). Patients were divided into tertiles of T_end [Group 1: <4 min; Group 2: 4–6 min; Group 3: >6 min]. Disease severity (FEV₁), aerobic fitness (W_peak, peak oxygen consumption [_peak], ventilatory threshold [_VT]), quadriceps strength (MVC), symptom scores at the end of CET and exercise intensity during CET (heart rate at the end of CET to heart rate at peak incremental exercise ratio [HR_CET/HR_peak]) were analyzed as potential variables influencing T_end.

Results

W_peak, _peak, _VT, MVC, leg fatigue at end of CET, and HR_CET/HR_peak were lower in group 1 than in group 2 or 3 (p≤0.05). _VT and leg fatigue at end of CET independently predicted T_end in multiple regression analysis (r = 0.50, p = 0.001).

Conclusion

T_end was independently related to the aerobic fitness and to tolerance to leg fatigue at the end of exercise. A large fraction of the variability in T_end was not explained by the physiological parameters assessed in the present study. Individualization of exercise intensity during CET should help in reducing variations in T_end among patients with COPD.

The endurance shuttle walk test: An alternative to the six-minute walk test for the assessment of ambulatory oxygen

UK guidelines for domiciliary oxygen have suggested the six-minute walk test or shuttle walk tests as suitable functional measures for the clinical assessment of ambulatory oxygen (AO). To date, there is limited evidence that would support the use of shuttle walk tests as assessment tools for AO. The endurance shuttle walk test (ESWT) is used increasingly as an assessment tool within pulmonary rehabilitation (PR) but its potential as an investigative test for AO has not been explored. Using the same test for both PR and AO assessment is appealing since it would improve efficiency and act to standardise outcome measures in this patient population. The aim of this study was to examine the responsiveness and repeatability of the ESWT to AO and to compare the response with that of the six-minute walk test (6MWT). Twenty-three patients with chronic obstructive pulmonary disease (COPD) performed, in random order, the ESWT and the 6MWT on air and whilst breathing AO. Oxygen saturation and Borg ratings of breathlessness and perceived exertion were recorded. On a third day, eleven patients repeated the ESWT with AO in order to measure repeatability. There was a significantly greater change in the ESWT with oxygen than the change recorded from the 6MWT (66 [91] vs 6 [28] m respectively; P < .05). When repeated on a separate day, the mean difference (95% CI) between distances walked on the ESWT with AO was 0.91 (-47, 49) m. The ESWT was more responsive than the 6MWT for detecting improvements in walking endurance whilst breathing AO.

Acute administration of bronchodilators on exercise tolerance in treated COPD patients

Exercise intolerance is a major feature in patients with Chronic Obstructive Pulmonary Disease (COPD). Bronchodilators increase endurance time (ET) and reduce dynamic hyperinflation (DH). We evaluated whether a single-dose of salbutamol/ipratropium + flunisolide (BD+ICS), added on top of the regular treatment, may improve ET in COPD patients. In a single-blind randomized crossover pilot trial, nebulised BD+ICS or placebo (PL) was administered 30 min before a constant load cardiopulmonary test, in 22 moderate-to-severe COPD patients (FEV₁: 53.9% pred). ET was the primary outcome measured. BD+ICS did not improve ET or VO₂ peak with respect to PL. BD+ICS increased pre-test FEV₁ and pre-test Inspiratory Capacity but did not modify DH. In a retrospective analysis, patients were divided in Improvers (N=11) and Non-Improvers (N=11) according to the difference in ET between BD+ICS and PL (> 25 s). Improvers had a worst BODE index, a higher static hyperinflation and poorer Vd/Vt ratio at peak of exercise with respect to Non-Improvers. Improvers only had a significant increase from BD+ICS on pre-test FEV₁ and IC. In conclusion, although a single-dose BD+ICS did not improve ET in COPD patients under regular treatment, a subgroup of more severe patients may have some benefit from that.

Impact of bronchodilator therapy on exercise tolerance in COPD

Exercise tolerance is an important parameter in patients with COPD and a primary goal of treatment is to reduce dyspnea to facilitate physical activities and improve health-related quality of life. This review examines the link between expiratory flow limitation and dyspnea to explain the rationale for the use of bronchodilators and review the characteristics of different types of exercise tests, with specific focus on which tests are likely to show a response to bronchodilators. An earlier literature search of studies published up to 1999 assessed the effects of bronchodilatort therapy on dypsnea and exercise tolerance among patients with COPD. This current review examines the clinical evidence published since 1999. Thirty-one randomized studies of exercise tolerance associated with short- and long-acting beta(2)-agonists and anticholinergics were identified. Evidence for the efficacy of bronchodilators in enhancing exercise capacity is often contradictory and possibly depends on the exercise test and study methodology. However, further studies should confirm the benefit of long-acting bronchodilators in improving spontaneous everyday physical activities.

Advantages of endurance treadmill walking compared with cycling to assess bronchodilator therapy

BACKGROUND

Walking is a familiar daily activity that is generally limited by breathlessness, whereas cycling is an uncommon physical effort typically limited by leg discomfort. The hypothesis was that patients with COPD would exhibit greater improvements in exercise endurance and relief of breathlessness with bronchodilator therapy during treadmill walking compared with cycling.

METHODS

In this randomized, 2 x 2, double-blind, placebo-controlled, crossover trial, 20 patients with COPD (age, 64 +/- 7 years; FEV(1), 56 +/- 14% predicted) performed constant-load endurance exercise on the treadmill and cycle ergometer at 85% of capacity after inhaling normal saline (NS) or arformoterol (ARF) (15 microg).

RESULTS

Increases in endurance times and consistency of responses were greater with treadmill walking (Delta: 157 +/- 286 s; P = .024; 80% improved) than with cycle exercise (Delta: 110 +/- 219 s; P = .038; 65% improved) with ARF compared with NS. However, these changes were not significantly different. The slope of breathlessness-time (mean Delta = -29%; P = .007) and the magnitude of oxygen desaturation were significantly lower with ARF compared with NS during treadmill, but not cycle, exercise. Inspiratory capacity values were similar between modes of exercise when comparing the same study medication.

CONCLUSIONS

Improved endurance times support both constant-load treadmill and cycle exercise to assess the efficacy of bronchodilator therapy in patients with COPD. Unique differences in physiologic and perceptual responses with bronchodilation demonstrate advantages of treadmill walking as an exercise stimulus.

TRIAL REGISTRATION

clinicaltrials.gov; Identifier: NCT00754546.

Perceptual and physiologic responses during treadmill and cycle exercise in patients with COPD

BACKGROUND

Although the cycle ergometer is the traditional mode for exercise testing in patients with respiratory disease, this preference over the treadmill does not consider perceptual responses. Our hypotheses were as follows: (1) the regression slope between breathlessness and oxygen consumption (Vo(2)) is greater on the treadmill than on the cycle ergometer; and (2) the regression slope between leg discomfort and Vo(2) is greater on the cycle ergometer than on the treadmill.

METHODS

Twenty patients (10 men/10 women) with COPD (mean +/- SD postbronchodilator FEV(1), 50 +/- 15% of predicted) used a continuous method to report changes in breathlessness and in leg discomfort during cycle and treadmill exercise.

RESULTS

Patients reported an earlier onset of breathlessness and leg discomfort during cycling. Peak ratings of breathlessness were higher on the treadmill, whereas peak ratings of leg discomfort were higher on the cycle ergometer. The regression slopes for breathlessness as a function of Vo(2) and of minute ventilation (Ve) were higher on the treadmill. The regression slopes between leg discomfort and Vo(2) were similar for treadmill and cycle exercise. Peak Vo(2) was significantly higher with treadmill exercise (mean Delta = 8%; p = 0.002).

CONCLUSIONS

Patients with COPD exhibit different perceptual and physiologic responses during treadmill walking and cycling. Although ratings of breathlessness are initially higher with cycling at equivalent levels of Vo(2), the changes in breathlessness as a function of physiologic stimuli (Vo(2) and Ve) are greater during treadmill exercise. Leg discomfort is the predominant symptom throughout cycling.