Catherine J. Hill

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. Technical Standard document: standard operating procedures for the 6MWT, ISWT and ESWT in chronic respiratory disease http://ow.ly/Bq2B9

Updating the minimal important difference for six-minute walk distance in patients with chronic obstructive pulmonary disease.

OBJECTIVE To establish the minimal important difference (MID) for the six-minute walk distance (6MWD) in persons with chronic obstructive pulmonary disease (COPD). DESIGN Analysis of data from an observational study using distribution- and anchor-based methods to determine the MID in 6MWD. SETTING Outpatient pulmonary rehabilitation program at 2 teaching hospitals. PARTICIPANTS Seventy-five patients with COPD (44 men) in a stable clinical state with mean age 70 years (SD 9 y), forced expiratory volume in one second 52% (SD 21%) predicted and baseline walking distance 359 meters (SD 104 m). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Participants completed the six-minute walk test before and after a 7-week pulmonary rehabilitation program. Participants and clinicians completed a global rating of change score while blinded to the change in 6MWD. RESULTS The mean change in 6MWD in participants who reported themselves to be unchanged was 17.7 meters, compared with 60.2 meters in those who reported small change and 78.4 meters in those who reported substantial change (P=.004). Anchor-based methods identified an MID of 25 meters (95% confidence interval 20-61 m). There was excellent agreement with distribution-based methods (25.5-26.5m, kappa=.95). A change in 6MWD of 14% compared with baseline also represented a clinically important effect; this threshold was less sensitive than for absolute change (sensitivity .70 vs .85). CONCLUSIONS The MID for 6MWD in COPD is 25 meters. Absolute change in 6MWD is a more sensitive indicator than percentage change from baseline. These data support the use of 6MWD as a patient-important outcome in research and clinical practice.

Short term improvement in exercise capacity and symptoms following exercise training in interstitial lung disease

Background: Interstitial lung disease (ILD) is characterised by exertional dyspnoea, exercise limitation and reduced quality of life. The role of exercise training in this diverse patient group is unclear. The aims of this study were to establish the safety of exercise training in ILD; its effects on exercise capacity, dyspnoea and quality of life; and whether patients with idiopathic pulmonary fibrosis (IPF) had similar responses to those with other types of ILD. Methods: 57 subjects with ILD (34 IPF) were randomised to receive 8 weeks of supervised exercise training or weekly telephone support. The 6 min walk distance (6MWD), incremental exercise test, modified Medical Research Council (MRC) dyspnoea score and Chronic Respiratory Disease Questionnaire (CRDQ) were performed at baseline, following intervention and at 6 months. Results: 80% of subjects completed the exercise programme and no adverse events were recorded. The 6MWD increased following training (mean difference to control 35 m, 95% CI 6 to 64 m). A significant reduction in MRC score was observed (0.7 points, 95% CI 0.1 to 1.3) along with improvements in dyspnoea (p = 0.04) and fatigue (p<0.01) on the CRDQ. There was no change in peak oxygen uptake; however, exercise training reduced heart rate at maximum isoworkload (p = 0.01). There were no significant differences in response between those with and without IPF. After 6 months there were no differences between the training and control group for any outcome variable. Conclusions: Exercise training improves exercise capacity and symptoms in patients with ILD, but these benefits are not sustained 6 months following intervention. Trial registration number: NCT00168285

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. Systematic review: support for use of the 6MWT, ISWT and ESWT in adults with chronic respiratory disease http://ow.ly/Bq2Mz

Pulmonary hypertension in COPD: results from the ASPIRE registry

The phenotype and outcome of severe pulmonary hypertension in chronic obstructive pulmonary disease (COPD) is described in small numbers, and predictors of survival are unknown. Data was retrieved for 101 consecutive, treatment-naïve cases of pulmonary hypertension in COPD. Mean±sd follow-up was 2.3±1.9 years. 59 patients with COPD and severe pulmonary hypertension, defined by catheter mean pulmonary artery pressure ≥40 mmHg, had significantly lower carbon monoxide diffusion, less severe airflow obstruction but not significantly different emphysema scores on computed tomography compared to 42 patients with mild–moderate pulmonary hypertension. 1- and 3-year survival for severe pulmonary hypertension, at 70% and 33%, respectively, was inferior to 83% and 55%, respectively, for mild–moderate pulmonary hypertension. Mixed venous oxygen saturation, carbon monoxide diffusion, World Health Organization functional class and age, but not severity of airflow obstruction, were independent predictors of outcome. Compassionate treatment with targeted therapies in 43 patients with severe pulmonary hypertension was not associated with a survival benefit, although improvement in functional class and/or fall in pulmonary vascular resistance >20% following treatment identified patients with improved survival. Standard prognostic markers in COPD have limited value in patients with pulmonary hypertension. This study identifies variables that predict outcome in this phenotype. Despite poor prognosis, our data suggest that further evaluation of targeted therapies is warranted.

Small changes in six-minute walk distance are important in diffuse parenchymal lung disease

UNLABELLED The aim of this study was to determine the minimal important difference for the six-minute walk distance in people with diffuse parenchymal lung disease. METHODS Forty-eight subjects (24 idiopathic pulmonary fibrosis) undertook the six-minute walk test before and after an 8-week exercise program. The minimal important difference was calculated using a distribution-based and an anchor-based method. A global rating of change scale was used as the external criterion to judge patients as clinically unchanged or changed. RESULTS The mean change in six-minute walk distance in improved subjects was 50.0 m, compared to 4.0 m in unchanged subjects and a reduction of 64.3 m in those classified as worse (p<0.001). The receiver operating characteristic curve indicated a cut-off value for meaningful change of 30.5 m (area under the curve 0.89, 95% confidence interval 0.81-0.98) whilst the standard error of the mean method indicated a value of 33 m. Similar values were obtained when only subjects with idiopathic pulmonary fibrosis were included (29 and 34 m, respectively). CONCLUSIONS Small differences in six-minute walk distance, in the range 29-34 m, may be clinically significant for people with diffuse parenchymal lung disease.

Quantitative analysis of regional airways obstruction using dynamic hyperpolarized 3He MRI—Preliminary results in children with cystic fibrosis

To investigate regional airways obstruction in patients with cystic fibrosis (CF) with quantitative analysis of dynamic hyperpolarized (HP) 3He MRI.

Ventricular mass index correlates with pulmonary artery pressure and predicts survival in suspected systemic sclerosis-associated pulmonary arterial hypertension

OBJECTIVE The ventricular mass index (VMI) has been proposed as a diagnostic tool for the assessment of patients with suspected pulmonary hypertension (PH). We hypothesized that in patients with SSc it may predict the presence or absence of PH. METHODS Details of all consecutive SSc patients undergoing MRI and right heart catheterization were collected prospectively. Subsequently, the VMI for all patients was calculated, and further baseline data were collected. RESULTS Data for 40 patients, 28 of whom were diagnosed with PH at rest (PH(REST)), were analysed. VMI correlated strongly with mean pulmonary artery pressure (mPAP; r = 0.79). Using a VMI threshold of 0.56, positive predictive value (PPV) for PH(REST) was 88% and negative predictive value (NPV) was 100%. Using a threshold of 0.7, PPV was found to be 100% and NPV 53%. Echocardiographically obtained tricuspid gradient (TG) also demonstrated a strong correlation with mPAP. Two-year survival in patients with VMI <0.7 and > or =0.7 was 91 and 43%, respectively (P < 0.001). CONCLUSION VMI correlates well with mPAP in patients with SSc and may have a role in non-invasively excluding clinically significant PH in breathless SSc patients in whom echocardiographic screening has failed. Further study in larger groups of patients is justified.

Does unsupported upper limb exercise training improve symptoms and quality of life for patients with chronic obstructive pulmonary disease

PURPOSE Many patients with chronic obstructive pulmonary disease (COPD) report dyspnea and fatigue when performing upper limb activities. Unsupported upper limb training has been shown to improve upper limb endurance, but its effects on symptoms and quality of life have not been examined. The aim of this study was to compare the effects of upper limb and lower limb training with lower limb training alone on exercise capacity, symptoms, and quality of life with COPD. METHODS For this study, 38 patients with moderate to severe COPD were randomly allocated to unsupported upper limb endurance training or to a control group that completed a sham training task. All the patients underwent lower limb endurance training. The 6-minute walk test, the Incremental Unsupported Upper Limb Exercise Test, and the Chronic Respiratory Disease Questionnaire (CRQ) were completed before training and then 6 weeks afterward. Both patients and assessors were blinded to group allocation. RESULTS All the patients reported symptoms associated with upper limb activities on the initial CRQ. Both groups showed significant improvements in all domains of the CRQ and in the 6-minute walk test after training. Only the upper limb training group showed improvement in upper limb endurance time (57 +/- 75 vs 2 +/- 58 seconds; P = .02). There were no significant differences between the groups for 6-minute walk test or any domain of the CRQ. CONCLUSIONS Unsupported upper limb training for patients COPD improves upper limb exercise capacity, but has no additional effect on symptoms or quality of life, as compared with leg training alone. This type of upper limb training may not adequately address the complex interaction between respiratory mechanics and upper limb function.

Home-based rehabilitation for COPD using minimal resources: a randomised, controlled equivalence trial

Background Pulmonary rehabilitation is a cornerstone of care for COPD but uptake of traditional centre-based programmes is poor. We assessed whether home-based pulmonary rehabilitation, delivered using minimal resources, had equivalent outcomes to centre-based pulmonary rehabilitation. Methods A randomised controlled equivalence trial with 12 months follow-up. Participants with stable COPD were randomly assigned to receive 8 weeks of pulmonary rehabilitation by either the standard outpatient centre-based model, or a new home-based model including one home visit and seven once-weekly telephone calls from a physiotherapist. The primary outcome was change in 6 min walk distance (6MWD). Results We enrolled 166 participants to receive centre-based rehabilitation (n=86) or home-based rehabilitation (n=80). Intention-to-treat analysis confirmed non-inferiority of home-based rehabilitation for 6MWD at end-rehabilitation and the confidence interval (CI) did not rule out superiority (mean difference favouring home group 18.6 m, 95% CI −3.3 to 40.7). At 12 months the CI did not exclude inferiority (−5.1 m, −29.2 to 18.9). Between-group differences for dyspnoea-related quality of life did not rule out superiority of home-based rehabilitation at programme completion (1.6 points, −0.3 to 3.5) and groups were equivalent at 12 months (0.05 points, −2.0 to 2.1). The per-protocol analysis showed the same pattern of findings. Neither group maintained postrehabilitation gains at 12 months. Conclusions This home-based pulmonary rehabilitation model, delivered with minimal resources, produced short-term clinical outcomes that were equivalent to centre-based pulmonary rehabilitation. Neither model was effective in maintaining gains at 12 months. Home-based pulmonary rehabilitation could be considered for people with COPD who cannot access centre-based pulmonary rehabilitation. Trial registration number NCT01423227, clinicaltrials.gov.