Phenotypic characteristics associated with slow gait speed in idiopathic pulmonary fibrosis.

BACKGROUND AND OBJECTIVE: Usual gait speed over 4 m (4MGS) is an established functional performance measure in older adults that consistently predicts adverse health outcomes, but few data exist in idiopathic pulmonary fibrosis (IPF). We assessed the reliability of 4MGS, its relationship with established outcome measures and its responsiveness to pulmonary rehabilitation. METHODS: In four prospective IPF cohorts, 4MGS inter-observer (n = 46) and test-retest (n = 46) reliability, concurrent validity (n = 65 and n = 62) and responsiveness (n = 60) were determined. The phenotypic characteristics of all patients stratified according to slow 4MGS (<0.8 m/s) were compared, including lung function parameters, HRCT of the chest, 6-min walking distance (6MWD), Medical Respiratory Council (MRC) dyspnoea score, King's Brief Interstitial Lung Disease (KBILD) questionnaire and Gender, Age and lung Physiology (GAP) prognostic index. RESULTS: Intra-class correlation coefficients for inter-observer and test-retest reliability were 0.996 and 0.983, respectively. There was a strong association between 4MGS and 6MWD (r = 0.76; P < 0.0001) and moderate correlations with MRC (r = -0.56), KBILD (r = 0.44) and GAP index (r = -0.41); all P < 0.005. 4MGS improved significantly with pulmonary rehabilitation (mean (95% CI) change: 0.16 (0.12-0.20) m/s), effect size 0.65. Patients with slow 4MGS had significantly worse exercise performance (6MWD: -167 (-220 to -133) m), dyspnoea, health status and prognosis index than those with preserved 4MGS, despite similar lung function and HRCT parameters. CONCLUSION: 4MGS is a simple, reliable, valid and responsive tool that may detect a patient phenotype with worse exercise performance, dyspnoea, health status and prognosis index in stable IPF.

Pedometer Step Count Targets during Pulmonary Rehabilitation in Chronic Obstructive Pulmonary Disease. A Randomized Controlled Trial.

RATIONALE: Increasing physical activity is a key therapeutic aim in chronic obstructive pulmonary disease (COPD). Pulmonary rehabilitation (PR) improves exercise capacity, but there is conflicting evidence regarding its ability to improve physical activity levels. OBJECTIVES: To determine whether using pedometers as an adjunct to PR can enhance time spent in at least moderate-intensity physical activity (time expending ≥3 metabolic equivalents [METs]) by people with COPD. METHODS: In this single-blind randomized controlled trial, participants were assigned 1:1 to receive a control intervention (PR comprising 8 wk, two supervised sessions per week) or the trial intervention (PR plus pedometer-directed step targets, reviewed weekly for 8 wk). In the randomization process, we used minimization to balance groups for age, sex, FEV1 percent predicted, and baseline exercise capacity and physical activity levels. Outcome assessors and PR therapists were blinded to group allocation. The primary analysis was based on the intention-to-treat principle. MEASUREMENTS AND MAIN RESULTS: The primary outcome was change from baseline to 8 weeks in accelerometer-measured daily time expending at least 3 METs. A total of 152 participants (72% male; mean [SD] FEV1 percent predicted, 50.5% [21.2]; median [first quartile, third quartile] time expending ≥3 METs, 46 [21, 92] min) were enrolled and assigned to the intervention (n = 76) or control (n = 76) arm. There was no significant difference in change in time expending at least 3 METs between the intervention and control groups at 8 weeks (median [first quartile, third quartile] difference, 0.5 [-1.0, 31.0] min; P = 0.87) or at the 6-month follow-up (7.0 [-9, 27] min; P = 0.16). CONCLUSIONS: Pedometer-directed step-count targets during an outpatient PR program did not enhance moderate-intensity physical activity levels in people with COPD. Clinical trial registered with www.clinicaltrials.gov (NCT01719822).

Physical frailty and pulmonary rehabilitation in COPD: a prospective cohort study.

BACKGROUND: Frailty is an important clinical syndrome that is consistently associated with adverse outcomes in older people. The relevance of frailty to chronic respiratory disease and its management is unknown. OBJECTIVES: To determine the prevalence of frailty among patients with stable COPD and examine whether frailty affects completion and outcomes of pulmonary rehabilitation. METHODS: 816 outpatients with COPD (mean (SD) age 70 (10) years, FEV1% predicted 48.9 (21.0)) were recruited between November 2011 and January 2015. Frailty was assessed using the Fried criteria (weight loss, exhaustion, low physical activity, slowness and weakness) before and after pulmonary rehabilitation. Predictors of programme non-completion were identified using multivariate logistic regression, and outcomes were compared using analysis of covariance, adjusting for age and sex. RESULTS: 209/816 patients (25.6%, 95% CI 22.7 to 28.7) were frail. Prevalence of frailty increased with age, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage, Medical Research Council (MRC) score and age-adjusted comorbidity burden (all p≤0.01). Patients who were frail had double the odds of programme non-completion (adjusted OR 2.20, 95% CI 1.39 to 3.46, p=0.001), often due to exacerbation and/or hospital admission. However, rehabilitation outcomes favoured frail completers, with consistently better responses in MRC score, exercise performance, physical activity level and health status (all p<0.001). After rehabilitation, 71/115 (61.3%) previously frail patients no longer met case criteria for frailty. CONCLUSIONS: Frailty affects one in four patients with COPD referred for pulmonary rehabilitation and is an independent predictor of programme non-completion. However, patients who are frail respond favourably to rehabilitation and their frailty can be reversed in the short term.

The EQ-5D-5L health status questionnaire in COPD: validity, responsiveness and minimum important difference.

BACKGROUND: The EQ-5D, a generic health status questionnaire that is widely used in health economic evaluation, was recently expanded to the EQ-5D-5L to address criticisms of unresponsiveness and ceiling effect. AIMS: To describe the validity, responsiveness and minimum important difference of the EQ-5D-5L in COPD. METHODS: Study 1: The validity of the EQ-5D-5L utility index and visual analogue scale (EQ-VAS) was compared with four established disease-specific health status questionnaires and other measures of disease severity in 616 stable outpatients with COPD. Study 2: The EQ-5D-5L utility index and EQ-VAS were measured in 324 patients with COPD before and after 8 weeks of pulmonary rehabilitation. Distribution and anchor-based approaches were used to estimate the minimum important difference. RESULTS: There were moderate-to-strong correlations between utility index and EQ-VAS with disease-specific questionnaires (Pearson's r=0.47-0.72). A ceiling effect was seen in 7% and 2.6% of utility index and EQ-VAS. Utility index decreased (worsening health status) with indices of worsening disease severity. With rehabilitation, mean (95% CI) changes in utility index and EQ-VAS were 0.065 (0.047 to 0.083) and 8.6 (6.5 to 10.7), respectively, with standardised response means of 0.39 and 0.44. The mean (range) anchor estimates of the minimum important difference for utility index and EQ-VAS were 0.051 (0.037 to 0.063) and 6.9 (6.5 to 8.0), respectively. CONCLUSIONS: The EQ-5D-5L is a valid and responsive measure of health status in COPD and may provide useful additional cost-effectiveness data in clinical trials.

Sarcopenia in COPD: prevalence, clinical correlates and response to pulmonary rehabilitation.

BACKGROUND: Age-related loss of muscle, sarcopenia, is recognised as a clinical syndrome with multiple contributing factors. International European Working Group on Sarcopenia in Older People (EWGSOP) criteria require generalised loss of muscle mass and reduced function to diagnose sarcopenia. Both are common in COPD but are usually studied in isolation and in the lower limbs. OBJECTIVES: To determine the prevalence of sarcopenia in COPD, its impact on function and health status, its relationship with quadriceps strength and its response to pulmonary rehabilitation (PR). METHODS: EWGSOP criteria were applied to 622 outpatients with stable COPD. Body composition, exercise capacity, functional performance, physical activity and health status were assessed. Using a case-control design, response to PR was determined in 43 patients with sarcopenia and a propensity score-matched non-sarcopenic group. RESULTS: Prevalence of sarcopenia was 14.5% (95% CI 11.8% to 17.4%), which increased with age and Global Initiative for Chronic Obstructive Pulmonary Disease (GOLD) stage, but did not differ by gender or the presence of quadriceps weakness (14.9 vs 13.8%, p=0.40). Patients with sarcopenia had reduced exercise capacity, functional performance, physical activity and health status compared with patients without sarcopenia (p<0.001), but responded similarly following PR; 12/43 patients were no longer classified as sarcopenic following PR. CONCLUSIONS: Sarcopenia affects 15% of patients with stable COPD and impairs function and health status. Sarcopenia does not impact on response to PR, which can lead to a reversal of the syndrome in select patients.

Gait speed and readmission following hospitalisation for acute exacerbations of COPD: a prospective study.

BACKGROUND: Hospitalisation for acute exacerbations of COPD is associated with high risk of readmission. However, no tool has been validated to stratify patients at discharge for risk of readmission. AIM: To evaluate the ability of the 4 m gait speed (4MGS), a surrogate marker of frailty, to predict risk of future readmission in hospitalised patients with an acute exacerbation of COPD (AECOPD). METHODS: 213 patients hospitalised with an AECOPD were recruited prospectively. 4MGS was measured on day of discharge. Logistic regression models were used to assess the association between 4MGS and readmission at 90 days after discharge. RESULTS: Baseline characteristics of the cohort: 52% men; mean age 72 years; median FEV1 35%predicted. Mean (SD) 4MGS at hospital discharge was 0.61 (0.26) ms(-1). Significant increased rates of all-cause readmission at 90 days were seen across quartiles of decreasing 4MGS (Q4 fastest: 11.5%; Q3: 20.4%; Q2: 30.2%; Q1 slowest: 48.2%; p trend<0.001). Compared with Q4, those in the slowest 4MGS quartile had unadjusted ORs (95% CIs) for 90-day readmission of 7.12 (2.61 to 19.44) for the whole cohort and 11.56 (3.08 to 43.35) in those aged 65 or over. A multivariate model incorporating 4MGS, Charlson Index, hospital admission in past year, FEV1%predicted and number of exacerbations in past year in those aged 65 or over predicted 90-day readmission with a C-statistic of 0.86. CONCLUSIONS: The 4MGS, a surrogate marker of physical frailty, independently predicts the risk of readmission in older patients hospitalised for acute exacerbation of COPD. TRIAL REGISTRATION NUMBER: NCT01507415.

Does pulmonary rehabilitation reduce peripheral blood pressure in patients with chronic obstructive pulmonary disease?

Pulmonary rehabilitation (PR) can improve aerobic exercise capacity, health-related quality of life and dyspnoea in patients with chronic obstructive pulmonary disease (COPD). Recent studies have suggested that exercise training may improve blood pressure and arterial stiffness, albeit in small highly selected cohorts. The aim of the study was to establish whether supervised outpatient or unsupervised home PR can reduce peripheral blood pressure. Resting blood pressure was measured in 418 patients with COPD before and after outpatient PR, supervised by a hospital-based team (HOSP). Seventy-four patients with COPD undergoing an unsupervised home-based programme acted as a comparator group (HOME). Despite significant improvements in mean (95% confidence interval) exercise capacity in the HOSP group (56 (50-60) m, p < 0.001) and HOME group (30 (17-42) m, p < 0.001) systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial blood pressure (MAP) did not change in either the HOSP (SBP: p = 0.47; DBP: p = 0.06; MAP: p = 0.38) or HOME group (SBP: p = 0.67; DBP: p = 0.38; MAP: p = 0.76). Planned subgroup analysis of HOSP patients with known hypertension and/or cardiovascular disease showed no impact of PR upon blood pressure. PR is unlikely to reduce blood pressure, and by implication, makes a mechanism of action in which arterial stiffness is reduced, less likely.

The Clinical COPD Questionnaire: response to pulmonary rehabilitation and minimal clinically important difference.

BACKGROUND: The Clinical COPD Questionnaire (CCQ) is a simple 10-item, health-related quality of life questionnaire (HRQoL) with good psychometric properties. However, little data exists regarding the responsiveness of the CCQ to pulmonary rehabilitation (PR) or the minimal clinically important difference (MCID). The study aims were to assess the responsiveness of the CCQ to PR, to compare the responsiveness of the CCQ to other HRQoL questionnaires and to provide estimates for the MCID. METHODS: The CCQ, St George's Respiratory Questionnaire (SGRQ), Chronic Respiratory Questionnaire (CRQ) and COPD Assessment Test (CAT) were measured in 261 patients with COPD before and after outpatient PR. Pre to post PR changes and Cohen's effect size were calculated. Changes in CCQ were compared with changes in other HRQoL questionnaires. Using an anchor-based approach and receiver operating characteristic (ROC) curves, the CCQ change cutoffs that identified patients achieving the known MCID for other health status questionnaires with PR were identified. RESULTS: The CCQ, SGRQ, CRQ and CAT all significantly improved with PR with an effect size of -0.39, -0.33, 0.62 and -0.25, respectively. CCQ change correlated significantly with change in SGRQ, CRQ and CAT (r=0.48, -0.56, 0.54, respectively; all p<0.001). ROC curves consistently identified a CCQ change cutoff of -0.4 as the best discriminating value to identify the MCID for the SGRQ, CRQ and CAT (area under curve: 0.71, 0.75 and 0.77, respectively; all p<0.001). CONCLUSIONS: The CCQ is responsive to PR with an estimated clinically important improvement of -0.4 points. The CCQ is a practical alternative to more time-consuming measures of HRQoL.

The 4-metre gait speed in COPD: responsiveness and minimal clinically important difference.

Usual gait speed is a consistent predictor of adverse outcomes in community-dwelling elderly people. The reliability and validity of the 4-m gait speed (4MGS) has recently been demonstrated in patients with chronic obstructive pulmonary disease (COPD). The aims of this study were to assess the responsiveness of the 4MGS and to estimate the minimal clinically important difference (MCID). In 301 COPD patients, 4MGS and incremental shuttle walk (ISW) were measured before and after pulmonary rehabilitation. 4MGS and ISW were also measured at baseline and 1 year later in a separate cohort of 162 COPD patients. The MCID of 4MGS was estimated using distribution and anchor-based methods. 4MGS improved significantly with pulmonary rehabilitation (mean change 0.08 m·s(-1), p<0.001). The minimal detectable change at 95% confidence was 0.11 m·s(-1). The MCID was estimated at 0.11 m·s(-1) (anchored against ISW) and 0.08 m·s(-1) (anchored against self-reported improvement). The effect size for 4MGS was greatest in frail individuals. After 12 months, mean 4MGS declined by 0.04 m·s(-1). When anchored against a decline of more than the MCID for ISW, change in 4MGS was -0.11 m·s(-1). The 4MGS is responsive to pulmonary rehabilitation and longitudinal change in COPD, and has potential as a simple functional assessment tool in COPD. The 4MGS may be particularly useful in frail individuals with COPD.

Clinical COPD Questionnaire in patients with chronic respiratory disease.

BACKGROUND AND OBJECTIVE: The Clinical Chronic Obstructive Pulmonary Disease (COPD) Questionnaire (CCQ) is an easy to complete, health-related quality of life questionnaire which has been well-validated in COPD. The responsiveness of the CCQ in chronic respiratory disease patients other than COPD has not been previously described. The study aims were to determine if the CCQ in chronic respiratory disease correlates with other health related quality of life questionnaires, to assess the responsiveness of the CCQ to pulmonary rehabilitation and to determine the minimum important difference. METHODS: The CCQ, COPD Assessment Test (CAT), the Chronic Respiratory Questionnaire (CRQ) and St George's Respiratory Questionnaire (SGRQ) were measured in 138 chronic respiratory disease patients completing pulmonary rehabilitation. Change in CCQ with pulmonary rehabilitation was correlated with change in the other questionnaires. The minimum important difference of the CCQ was calculated using distribution and anchor-based approaches. RESULTS: The CCQ, CAT, CRQ and SGRQ improved significantly with rehabilitation with effect sizes of -0.43, -0.26, 0.62, -0.37. Change in CCQ correlated significantly with CAT, CRQ and SGRQ (r = 0.53, -0.64, 0.30, all P < 0.0001). The minimum important difference was -0.42 at the population level and -0.4 at the individual level. CONCLUSIONS: The CCQ is responsive to pulmonary rehabilitation in chronic respiratory disease patients, with an MID estimated at -0.4 at the individual level.

The five-repetition sit-to-stand test as a functional outcome measure in COPD.

BACKGROUND: Moving from sitting to standing is a common activity of daily living. The five-repetition sit-to-stand test (5STS) is a test of lower limb function that measures the fastest time taken to stand five times from a chair with arms folded. The 5STS has been validated in healthy community-dwelling adults, but data in chronic obstructive pulmonary disease (COPD) populations are lacking. AIMS: To determine the reliability, validity and responsiveness of the 5STS in patients with COPD. METHODS: Test-retest and interobserver reliability of the 5STS was measured in 50 patients with COPD. To address construct validity we collected data on the 5STS, exercise capacity (incremental shuttle walk (ISW)), lower limb strength (quadriceps maximum voluntary contraction (QMVC)), health status (St George's Respiratory Questionnaire (SGRQ)) and composite mortality indices (Age Dyspnoea Obstruction index (ADO), BODE index (iBODE)). Responsiveness was determined by measuring 5STS before and after outpatient pulmonary rehabilitation (PR) in 239 patients. Minimum clinically important difference (MCID) was estimated using anchor-based methods. RESULTS: Test-retest and interobserver intraclass correlation coefficients were 0.97 and 0.99, respectively. 5STS time correlated significantly with ISW, QMVC, SGRQ, ADO and iBODE (r=-0.59, -0.38, 0.35, 0.42 and 0.46, respectively; all p<0.001). Median (25th, 75th centiles) 5STS time decreased with PR (Pre: 14.1 (11.5, 21.3) vs Post: 12.4 (10.2, 16.3) s; p<0.001). Using different anchors, a conservative estimate for the MCID was 1.7 s. CONCLUSIONS: The 5STS is reliable, valid and responsive in patients with COPD with an estimated MCID of 1.7 s. It is a practical functional outcome measure suitable for use in most healthcare settings.

Reliability and validity of 4-metre gait speed in COPD.

In community-dwelling older adults, usual gait speed over 4 m (4MGS) consistently predicts greater risk of adverse health outcomes. The aims of the present study were to assess the reliability of the 4MGS and the relationship with established health outcome measures in chronic obstructive pulmonary disease (COPD). Test-retest and interobserver reliability of the 4MGS were measured in 80 and 58 COPD patients, respectively. In 586 COPD patients, the 4MGS, as well as forced expiratory volume in 1 s (FEV1), the incremental shuttle walk (ISW), Medical Research Council (MRC) dyspnoea scale and St George's Respiratory Questionnaire (SGRQ) were measured. Participants were stratified according to "slow" (<0.8 m·s(-1)) or "normal" 4MGS (≥0.8 m·s(-1)). Intra-class correlation coefficients for test-retest and interobserver reliability were 0.97 and 0.99, respectively. There was a significant positive correlation between 4MGS with ISW (ρ = 0.78; p<0.001) and a negative correlation with MRC dyspnoea scale and SGRQ (ρ = -0.55 and -0.44; p<0.001 for both). COPD patients with slow 4MGS had significantly reduced ISW and higher MRC dyspnoea scale and SGRQ than those with preserved walking speed, despite similar FEV1 % predicted. The 4MGS is reliable in COPD, correlates with exercise capacity, dyspnoea and health-related quality of life, and has potential as a simple assessment tool in COPD.

Response of the COPD Assessment Test to pulmonary rehabilitation in unselected chronic respiratory disease.

BACKGROUND AND OBJECTIVE: The COPD Assessment Test (CAT) is a recently introduced, simple-to-use health status instrument that takes less time to complete than better-established health status instruments. In chronic obstructive pulmonary disease (COPD) patients, the CAT improves with pulmonary rehabilitation (PR), and changes correlate with improvements in longer-established health status instruments such as the Chronic Respiratory Questionnaire (CRQ). Increasing numbers of non-COPD patients are referred for PR, but it is not known whether the CAT is responsive to PR in these populations. METHODS: The CAT score was prospectively measured in 365 consecutive patients (255 COPD, 110 non-COPD) before and after an 8-week PR programme. Pre to post change in CAT was calculated for COPD and non-COPD patients, and correlated with change in the CRQ. RESULTS: For both non-COPD and COPD patients, there was a similar and significant improvement in the mean (95% confidence interval) CAT score following PR (non-COPD: -2.1 (-1.0, -3.2) vs COPD: -3.0 (-2.2, -3.8); P = 0.19). Change in CAT was significantly correlated with all domains of the CRQ in non-COPD patients (all P < 0.01). CONCLUSIONS: As in COPD patients, the CAT is immediately responsive to PR in non-COPD patients. Even in unselected chronic respiratory disease patients undergoing PR, the CAT is a practical alternative to longer-established health status questionnaires.

Stanford Seven-Day Physical Activity Recall questionnaire in COPD.

Quantification of daily physical activity is of clinical interest in chronic obstructive pulmonary disease (COPD). Objective measures using activity monitors may take several days to obtain reliable results. The aim of our study was to evaluate the Stanford Seven-Day Physical Activity Recall questionnaire (PAR) against the SenseWear armband (SWA) and compare its validity with three other physical activity questionnaires. 43 COPD patients wore the SWA for 7 days. Patients completed the PAR, Baecke, Physical Activity Scale for the Elderly (PASE) and Zutphen questionnaires. Spearman rank correlation, intraclass correlation coefficients (ICC) and receiver-operating characteristics (ROC) curves were used to assess the relationship between the questionnaires and SWA. Assessed by PAR, time spent at ≥3.0 metabolic equivalents (METs) correlated significantly (r=0.54, p<0.001) with equivalent measures from SWA, with an ICC of 0.40. No relationship was seen between the other questionnaires and the SWA. The PAR predicted active patients (≥30 min at ≥3.0 METs or a physical activity level (PAL) ≥1.55) and very inactive patients (PAL <1.40) with an area under ROC curve of 0.83, 0.77 and 0.70, respectively. While the PAR did not measure physical activity sufficiently accurately to make individual recommendations, it was able to identify COPD patients at extremes of the physical activity spectrum, potentially reducing the number of patients requiring direct measurement.

The COPD Assessment Test (CAT): short- and medium-term response to pulmonary rehabilitation.

BACKGROUND: The COPD Assessment Test (CAT) is a recently introduced instrument to assess health-related quality of life in COPD. We aimed to evaluate the longitudinal change in CAT following Pulmonary Rehabilitation (PR), and test the relationship between CAT and CRQ-Self Report (SR) over time. We hypothesised that the CAT would show similar responsiveness to PR as the CRQ-SR both in the short and medium-term. METHODS: 118 COPD patients completed an eight-week outpatient multidisciplinary PR programme. CAT, CRQ-SR and the incremental shuttle walk (ISW) were measured prior to starting PR (T1), completion of PR (T2) and 6 months after completion of PR (T3). RESULTS: There was a significant improvement in CAT, CRQ-SR and ISW immediately following PR (p < 0.001). Although there was decline between T2 and T3, CAT, CRQ-SR and ISW remained significantly better at T3 compared with T1 (ANOVA p < 0.001). Both between T1-T2 and between T2-T3, change in CAT correlated significantly with change in CRQ (both r = -0.44 and p < 0.001). The slope of the relationship between CAT change and CRQ-SR change at T1-T2 and T2-T3 was not significantly different (ANCOVA: intercept p = 0.79, interaction effect p = 0.95). CONCLUSIONS: In COPD, the CAT score is immediately responsive to PR and remains improved at 6 months. There is no significant difference in the short and medium term changes in the CAT and CRQ-SR following PR. We propose that for most clinical indications for assessing health-related quality of life in COPD, the CAT is a robust and practical alternative to longer-established instruments such as the CRQ-SR.