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Background: The incremental shuttle walking test (ISWT) is used to assess exercise capacity in patients with chronic obstructive pulmonary disease (COPD) and is employed as an outcome measure for pulmonary rehabilitation. This study was designed to establish the minimum clinically important difference for the ISWT., Methods: 372 patients (205 men) performed an ISWT before and after a 7-week outpatient pulmonary rehabilitation programme. After completing the course, subjects were asked to identify, from a 5-point Likert scale, the perceived change in their exercise performance immediately upon completion of the ISWT. The scale ranged from "better" to "worse"., Results: The mean (SD) age was 69.4 (8.4) years, forced expiratory volume in 1 s (FEV(1)) 1.06 (0.53) l and FEV(1)/forced vital capacity (FVC) ratio 50.8 (18.1)%. The baseline shuttle walking test distance was 168.5 (114.6) m which increased to 234.7 (125.3) m after rehabilitation (mean difference 65.9 m (95% CI 58.9 to 72.9)). In subjects who felt their exercise tolerance was "slightly better" the mean improvement was 47.5 m (95% CI 38.6 to 56.5) compared with 78.7 m (95% CI 70.5 to 86.9) in those who reported that their exercise tolerance was "better" and 18.0 m (95% CI 4.5 to 31.5) in those who felt their exercise tolerance was "about the same"., Conclusion: Two levels of improvement were identified. The minimum clinically important improvement for the ISWT is 47.5 m. In addition, patients were able to distinguish an additional benefit at 78.7 m.

Background: The evidence of benefit for pulmonary rehabilitation (PR) programmes is established. However, the optimal duration of a PR programme is not known. A randomised controlled trial was undertaken in patients with chronic obstructive pulmonary disease (COPD) to assess whether a 4 week PR programme was equivalent to our conventional 7 week PR programme at equivalent time points of 7 weeks and 6 months., Methods: One hundred patients (56 men) with stable COPD of mean (SD) age 70 (8) years and forced expiratory volume in 1 second (FEV1) 1.13 (0.50) litres were randomised to either a 7 week (n = 50) or 4 week (n = 50) supervised PR programme. Patients were assessed at baseline, at completion of the supervised PR programme, and 6 months later. Patients randomised to the 4 week group were also assessed at the 7 week time point. Outcome measures were the Incremental Shuttle Walk Test, Endurance Shuttle Walk Test (ESWT), Chronic Respiratory Questionnaire-Self Reported, and the Breathing Problems Questionnaire., Results: Forty one patients in each group completed the PR programme. Patients made significant within group improvements after supervised rehabilitation. There were no statistically significant differences between the groups for any other measure at the 7 week or 6 month time points, except that patients in the 4 week group attained higher ESWT times (mean difference 124 seconds (95% CI 17.00 to 232.16), p = 0.024) at the 7 week time point., Conclusions: A shortened 4 week supervised PR programme is equivalent to a 7 week supervised PR programme at the comparable time points of 7 weeks and 6 months.

Background: Skeletal muscle adenine nucleotide loss has been associated with fatigue during high intensity exercise in healthy subjects but has not been studied in patients with chronic obstructive pulmonary disease (COPD). Changes in adenine nucleotides and other metabolites in the skeletal muscles were measured in patients with COPD and age matched healthy volunteers by obtaining biopsy samples from the quadriceps muscle at rest and following a standardised exercise challenge., Methods: Eighteen patients with COPD (mean (SD) forced expiratory volume in 1 second 38.1 (16.8)%) and eight age matched healthy controls were studied. Biopsy samples were taken from the vastus lateralis muscle at rest and immediately after a 5 minute constant workload cycle test performed at 80% peak work achieved during a maximal incremental cycle test performed previously., Results: The absolute workload at which exercise was performed was substantially lower in the COPD group than in the controls (56.7 (15.9) W v 143.2 (26.3) W, p<0.01). Despite this, there was a significant loss of adenosine triphosphate (mean change 4.3 (95% CI -7.0 to -1.6), p<0.01) and accumulation of inosine monophosphate (2.03 (95% CI 0.64 to 3.42), p<0.01) during exercise in the COPD group that was similar to the control group (-4.8 (95% CI -9.7 to 0.08), p = 0.053 and 1.6 (95% CI 0.42 to 2.79), p<0.01, respectively)., Conclusions: These findings indicate that the ATP demands of exercise were not met by resynthesis from oxidative and non-oxidative sources. This suggests that significant metabolic stress occurs in the skeletal muscles of COPD patients during whole body exercise at low absolute workloads similar to those required for activities of daily living.

Background: Pulmonary rehabilitation is effective in improving exercise performance and health status in chronic obstructive pulmonary disease (COPD). However, the role of nutritional support in the enhancement of the benefits of exercise training has not been explored. A double blind, randomised, controlled trial of carbohydrate supplementation was undertaken in patients attending outpatient pulmonary rehabilitation., Methods: 85 patients with COPD were randomised to receive a 570 kcal carbohydrate rich supplement or a non-nutritive placebo daily for the duration of a 7 week outpatient pulmonary rehabilitation programme. Primary outcome measures were peak and submaximal exercise performance using the shuttle walk tests. Changes in health status, body composition, muscle strength, and dietary macronutrient intake were also measured., Results: Patients in both the supplement and placebo groups increased shuttle walking performance and health status significantly. There was no statistically significant difference between treatment groups in these outcomes. Patients receiving placebo lost weight whereas supplemented patients gained weight. In well nourished patients (BMI >19 kg/m(2)) improvement in incremental shuttle performance was significantly greater in the supplemented group (mean difference between groups: 27 (95% CI 1 to 53) m, p<0.05). Increases in incremental shuttle performance correlated with increases in total carbohydrate intake., Conclusions: When universally prescribed, carbohydrate supplementation does not enhance the rehabilitation of patients with COPD. This study suggests that exercise training results in negative energy balance that can be overcome by supplementation and that, in selected patients, this may improve the outcome of training. The finding of benefit in well nourished patients may suggest a role for nutritional supplementation beyond the treatment of weight loss in COPD.

Background: A self-reported CRQ (CRQ-SR) has recently been developed and found to be a reproducible and reliable measure of health status. This study explores both the sensitivity of the CRQ-SR and relative sensitivity compared with the conventional interviewer led CRQ (CRQ-IL) in patients undergoing pulmonary rehabilitation., Methods: Eighty patients with stable chronic obstructive pulmonary disease who had been referred for pulmonary rehabilitation completed the CRQ-SR at initial assessment and at the end of the 7 week programme. A further 35 patients completed both the CRQ-SR and the CRQ-IL, administered 1 week apart, before starting rehabilitation and again at the end of the programme., Results: There were large statistically and clinically significant changes in mean score per dimension following rehabilitation in all dimensions of the CRQ-SR (dyspnoea mean difference 0.87 (95% CI 0.61 to 1.14); fatigue 0.76 (0.53 to 1.0); emotion 0.60 (0.35 to 0.86); mastery 0.76 (0.52 to 1.0); p<0.001). Similar results were found in the comparison of the sensitivity of the CRQ-SR and the CRQ-IL, with large changes in mean score per dimension following rehabilitation for both versions of the questionnaire (p<0.005). No significant differences were seen in the magnitude of change between the two formats of the questionnaire (p>0.05)., Conclusion: The self-reported CRQ is as sensitive to change as the interviewer led CRQ in patients undergoing pulmonary rehabilitation but has the advantage of being less time consuming to administer.

Background: Chronic cough is a common condition which has a significant impact on quality of life. Assessment and management are hampered by the absence of well validated outcome measures. The development and validation of the Leicester Cough Questionnaire (LCQ), a self-completed health related quality of life measure of chronic cough, is presented., Methods: Patients with chronic cough were recruited from outpatient clinics. The development of the LCQ consisted of three phases: phase 1 (item generation); phase 2 (item reduction, allocation of items to domains and validation of questionnaire); phase 3 (repeatability and responsiveness testing of final version of questionnaire)., Results: Phase 1: Literature review, multidisciplinary team meeting and 15 structured interviews with chronic cough patients generated 44 items (LCQ1) with a 7 point Likert response scale. Phase 2: 104 chronic cough outpatients completed the LCQ1 along with an importance rating for each item. The clinical impact factor method was used for item reduction to 19 items (LCQ2: final version). These items were divided into three domains (physical, psychological and social) following expert opinion. Internal reliability, as assessed using Cronbach's alpha coefficients, varied between 0.79 and 0.89. Concurrent validity was high when the LCQ2 (n=56) was compared with a cough visual analogue score (r=-0.72). There was a moderate relationship with response to the St George's Respiratory Questionnaire (r=-0.54) and SF36 total score (r=0.46). Phase 3: Two week repeatability (n=24) was high with intraclass correlation coefficients for domains varying between 0.88 and 0.96. Responsiveness in nine patients whose cough was successfully treated varied within domains from an effect size of 0.84 to 1.75., Conclusion: The LCQ is a valid, repeatable 19 item self-completed quality of life measure of chronic cough which is responsive to change. It should be a useful tool in clinical trials and longitudinal studies.

Background: There is a concern that comorbidity or frailty in older people could limit the usefulness of currently available exercise tests for chronic lung disease. This study evaluated the feasibility and reproducibility of the incremental shuttle walking test (SWT) in people aged 70 years or over, compared exercise tolerance with other disability markers, and assessed whether the SWT is responsive to change after bronchodilators., Methods: Fifty elderly patients with chronic airflow limitation (CAL) and 32 controls without airflow limitation attempted the SWT before and after combined nebulised salbutamol/ipratropium bromide. Subjects also completed the Nottingham Extended Activities of Daily Living index (NEADL) and the London Handicap score (LHS)., Results: Forty four subjects with CAL (88%) and 29 controls (84%) completed the SWT, including many with co-morbidities. Two week repeatability was good and the SWT was strongly associated with EADL (r=0.51, p<0.001) and LHS (r=0.43, p<0.004), but only weakly with forced expiratory volume in 1 second (FEV1) (r=0.31, p=0.05). Subjects with CAL walked a mean distance of 177.7 m compared with 243.3 m in controls (p<0.001); following bronchodilator therapy the distance walked increased in the CAL group by 13.2% (p=0.009)., Conclusion: The SWT is a feasible and reproducible measure of exercise tolerance in elderly people with and without airflow obstruction and correlates with other markers of disability. It is sensitive to change following bronchodilation in subjects with CAL, although the change correlates less well with improvements in FEV1. Overall, these results suggest that the SWT might be an appropriate measure to assess interventions in elderly people.

Background: The Chronic Respiratory Questionnaire (CRQ) is an established measure of health status for chronic obstructive pulmonary disease (COPD). It has been found to be reproducible and sensitive to change, but as an interviewer led questionnaire is very time consuming to administer. A study was undertaken to develop a self-reported version of the CRQ (CRQ-SR) and to compare the results of this questionnaire with the conventional interviewer led CRQ (CRQ-IL)., Methods: Fifty two patients with moderate to severe COPD participated in the study. Subjects completed the CRQ-SR 1 week after completing the CRQ-IL, and a further CRQ-SR was administered 1 week later. For patients in group A (n=27) the dyspnoea provoking activities that they had previously selected were transcribed onto the second CRQ-SR, while patients in group B (n=25) were not informed of their previous dyspnoea provoking activities when they completed the second CRQ-SR. To assess the short term reproducibility and reliability of the CRQ-SR it was then administered twice at an interval of 7-10 days to a further group of 21 patients. The CRQ-IL was not administered. Longer term reproducibility was examined in 39 stable patients who completed the CRQ-SR at initial assessment and then again 7 weeks later., Results: Mean scores per dimension, mean differences, and limits of agreement are given for each dimension in the comparison of the two questionnaires. There were no statistically significant differences between the CRQ-IL and CRQ-SR in the mastery and fatigue dimensions (p>0.05). A statistically significant difference between the two scores was found in the dyspnoea dimension (p=0.006) and the emotional function dimension (p=0.04), but these differences were well within the minimum clinically important threshold. No statistically significant difference in the mean dyspnoea score was seen between groups A and B. The CRQ-SR was found to be reproducible both in the short term and after the longer period of 7 weeks, with no statistically or clinically significant differences in any dimension. Test-retest reliability was found to be high in each dimension, both in the short and longer term., Conclusions: The CRQ-SR is a reproducible, reliable, and stable measure of health status. It compares well with the CRQ-IL but cannot be used interchangeably. The main advantage of the CRQ-SR over the CRQ-IL is that is quick to administer, reducing assessment time and hence cost.

Background: Pulmonary rehabilitation programmes have been shown to improve both exercise tolerance and health status in patients with chronic obstructive pulmonary disease (COPD). The optimal duration for a pulmonary rehabilitation programme is, however, unknown. To assess whether the current pulmonary rehabilitation programme could be shortened a randomised controlled trial was conducted in 44 patients with COPD who were allocated to either a seven week or a four week course., Methods: Patients were randomised to either our standard seven week twice weekly outpatient based programme or a comparable but shortened four week course. They were assessed at baseline and at completion by the Chronic Respiratory Questionnaire (CRQ), the Breathing Problems Questionnaire (BPQ), the incremental shuttle walking test (SWT), and the treadmill endurance test (TET)., Results: Twenty one patients (61% men) of mean (SD) age 68 (9.2) years and forced expiratory volume in one second ( FEV(1)) 1.08 (0.4) l completed a conventional seven week course and 23 (67% men) of mean (SD) age 69 (8.8) years and FEV(1) 1.03 (0.3) l completed a shortened four week course. Patients who completed the seven week rehabilitation programme had greater improvements in all outcome measures than those undertaking the four week course. These differences reached clinical and statistical significance for the total CRQ score, which was the primary outcome variable (mean difference (95% confidence intervals (CI) of difference) -0.61(-0.15 to -1.08), p<0.05), and the CRQ domains of dyspnoea (-0.80 (95% CI -0.13 to -1.48), p<0.05), emotion (-0.89 (95% CI -0.33 to -1.45), p<0.005), and mastery (-0.84 (95% CI -0.10 to -1.58), p<0.05). There were also trends towards greater improvements in exercise assessments in the seven week group but the differences did not reach statistical significance (SWT: mean difference -16.9 (95% CI 24.8 to -58.6), p=0.41; TET: geometric mean difference -1.21 (95% CI -0.60 to -2.47), p=0.56)., Conclusions: A seven week course of pulmonary rehabilitation provides greater benefits to patients than a four week course in terms of improvements in health status. Larger prospective studies are required to determine the optimal duration of a pulmonary rehabilitation programme.

Background: The purpose of this study was to develop an externally controlled, constant paced field walking test to assess endurance capacity in patients with chronic obstructive pulmonary disease (COPD). There were four objectives: (1) to develop a protocol; (2) to compare treadmill and shuttle walk tests of endurance capacity; (3) to examine the repeatability of the endurance shuttle walk test; and (4) to compare the sensitivity to pulmonary rehabilitation of endurance and incremental shuttle walk tests., Methods: The test was designed to complement the incremental shuttle walk test (ISWT) using the same 10 m shuttle course and an audio signal to control pace. The intensity of the field endurance test was related to a percentage of each patient's maximum field exercise performance assessed by the ISWT. A number of cassette tapes were pre-recorded with a range of audio signal frequencies to dictate walking speeds between 1.80 and 6.00 km/h. In the first limb of the study 10 patients with COPD (mean (SD) forced expiratory volume in one second (FEV1) 1.0 (0.36) 1, 35% predicted) performed three endurance shuttle walk tests (ESWTs) and three treadmill endurance tests. The walking speeds were calculated to elicit 75%, 85%, and 95% of each patient's maximum ISWT performance for the field tests and measured peak oxygen consumption for the treadmill tests. In a separate group of patients the repeatability of the ESWT at an intensity of 85% of the ISWT performance was evaluated. Finally, the ESWT (at the 85% intensity) and the ISWT were performed at the start of a five week control period and at the start and end of a seven week pulmonary rehabilitation programme in 21 patients with COPD (mean FEV1 0.80 (0.18) 1)., Results: The mean (SE) times achieved during the ESWT were 13.1 (2.3), 10.2 (2.5), and 5.3 (1.7) min for the walks at 75%, 85%, and 95% intensities, respectively. Patients tended to walk for longer on the treadmill than during the field tests at all intensities, but there were no significant differences between the end of test heart rates or Borg ratings of breathlessness or perceived exertion. Following one practice ESWT at the 85% intensity, the mean difference and limits of agreement (2SD) between tests 2 and 3 was +15 (42) s (p > 0.05). There was no significant change in performance on either test following the five week control period prior to rehabilitation. Following rehabilitation the ESWT duration increased by 160 (24)% and the ISWT distance increased by 32 (11)% (effect sizes 2.90 and 0.41, respectively)., Conclusions: The ESWT was simple to perform, acceptable to all patients, and exhibited good repeatability after one practice walk. The test showed major improvement following rehabilitation and was more sensitive to change than the field test of maximal capacity.

Background: Incremental threshold loading (ITL) is a test of inspiratory muscle performance which is usually performed by breathing through a weighted inspiratory plunger, the load on the inspiratory muscles being increased by externally adding weights to the intake valve. This is not a true threshold device and may be inaccurate. This method was compared with a true threshold device consisting of a solenoid valve which only opens to supply air at a predetermined negative mouth pressure., Methods: Six naive, normal subjects (three men and three women) aged 22-24 years underwent three tests using each system. The inspiratory loads were increased every minute by equivalent amounts, -10 cm H2O with the solenoid valve and by 50 g with the weighted plunger, until the subjects could not inspire or sustain inspiration for a full minute. Six experienced subjects (four men and two women) aged 23-41 years were subsequently randomised to perform ITL with the solenoid valve, twice with the breathing pattern fixed and twice free., Results: The solenoid valve generated a more accurate mouth pressure response and was less variable at higher loads than the weighted plunger. The work performed (expressed as the pressure-time product) was less with the solenoid valve but was more reproducible. ITL with the solenoid valve was not influenced by controlling the breathing pattern of the subjects., Conclusions: The solenoid valve has several features that make it superior to the weighted plunger as a device for ITL. It generates a more accurate mouth pressure response which is less variable at higher loads. Increases in load are smoother and quicker to introduce. ITL with the solenoid valve is not influenced by varying breathing patterns and does not require any external regulation.

Background: The aim was to develop a standardised and externally paced field walking test, incorporating an incremental and progressive structure, to assess functional capacity in patients with chronic airways obstruction., Methods: The usefulness of two different shuttle walking test protocols was examined in two separate groups of patients. The initial 10 level protocol (group A, n = 10) and a subsequent, modified, 12 level protocol (group B, n = 10) differed in the number of increments and in the speeds of walking. Patients performed three shuttle walking tests one week apart. Then the performance of patients (group C, n = 15) in the six minute walking test was compared with that in the second (modified) shuttle walking test protocol. Heart rate was recorded during all the exercise tests with a short range telemetry device., Results: The 12 level modified protocol provided a measure of functional capacity in patients with a wide range of disability and was reproducible after just one practice walk; the mean difference between trial 2 v 3 was -2.0 (95% CI -21.9 to 17.9) m. There was a significant relation between the distance walked in the six minute walking test and the shuttle walking test (rho = 0.68) but the six minute walking test appeared to overestimate the extent of disability in some patients. The shuttle test provoked a graded cardiovascular response not evident in the six minute test. Moreover, the maximal heart rates attained were significantly higher for the shuttle walking test than for the six minute test., Conclusions: The shuttle walking test constitutes a standardised incremental field walking test that provokes a symptom limited maximal performance. It provides an objective measurement of disability and allows direct comparison of patients' performance.