Six-minute walk test in pulmonary rehabilitation: do all patients need a practice test?

The role of exercise-based prehabilitation in enhancing surgical outcomes for patients with digestive system cancers: a meta-analysis

BACKGROUND

Prehabilitation is a crucial component of tumor rehabilitation that attempts to improve patients' preoperative health, although its efficacy in treating patients with cancers of the digestive system is still up for debate.

METHODS

The records from PubMed (MEDLINE), Embase, Web of Science, Cochrane Library, EBSCO, Scopus, CNKI and Wan fang database up to November 2024 were systematically searched. The Cochrane Collaboration tool was employed for evaluating the risk of bias in each study, and the PRISMA 2020 checklist provided by the EQUATOR network was utilized.

RESULTS

Through quality analysis, 20 articles were included, involving 1719 patients. Although its effect on severe complications is still unknown, the prehabilitation significantly decreased overall postoperative complications when compared to standard care, with a risk ratio (RR) of 0.74 (95% CI: 0.65 to 0.84). Despite not shortening the postoperative hospital stay (MD: -0.13, 95% CI: -0.29 to 0.03), prehabilitation demonstrated notable improvements in the 6-minute walk distance (6MWD), with preoperative gains (MD: 25.87, 95% CI: 14.49 to 37.25) and sustained benefits at 4 weeks postoperatively (MD: 22.48, 95% CI: 7.85 to 37.12). However, no significant differences in 6MWD were observed at 6 or 8 weeks postoperatively. The average improvement in 6MWD from baseline to preoperative was 28.99 (95% CI: 10.89 to 47.08, P = 0.002), and from 4 weeks postoperative to baseline, it was 25.95 (95% CI: 6.84 to 45.07, P = 0.008), with no significant change at 8 weeks. The acceptance and completion rates of prehabilitation were commendably high at 61% (95% CI: 47-75%) and 90% (95% CI: 87-93%), respectively, alongside a relatively low dropout rate of 10% (95% CI: 7% to13%).

CONCLUSIONS

Prehabilitation reduces postoperative complications and improves short-term physical function in digestive surgery patients, with good patient acceptance; however, the long-term effects are unknown due to a lack of follow-up data.

REGISTRATION

It was registered with the International Prospective Register of Systematic Reviews (PROSPERO) with the identification code CRD42022361100.

Assessing a GPS-Based 6-Minute Walk Test for People With Persistent Pain: Validation Study

BACKGROUND

The 6-minute walk test (6MWT) is a commonly used method to assess the exercise capacity of people with many health conditions, including persistent pain. However, it is conventionally performed with in-person supervision in a hospital or clinic, therefore requiring staff resources. It may also be difficult when in-person supervision is unavailable, such as during the COVID-19 pandemic, or when the person is geographically remote. A potential solution to these issues could be to use GPS to measure walking distance.

OBJECTIVE

The primary aim of this study was to assess the validity of a GPS-based smartphone app to measure walking distance as an alternative to the conventional 6MWT in a population with persistent pain. The secondary aim of this study was to estimate the difference between the pain evoked by the 2 test methods.

METHODS

People with persistent pain (N=36) were recruited to complete a conventional 6MWT on a 30-m shuttle track and a 6MWT assessed by a smartphone app using GPS, performed on outdoor walking circuits. Tests were performed in random order, separated by a 15-minute rest. The 95% limits of agreement were calculated using the Bland-Altman method, with a specified maximum allowable difference of 100 m. Pain was assessed using an 11-point numerical rating scale before and after each walk test.

RESULTS

The mean 6-minute walk distance measured by the GPS-based smartphone app was 13.2 (SD 46; 95% CI -2.7 to 29.1) m higher than that assessed in the conventional manner. The 95% limits of agreement were 103.9 (95% CI 87.4-134.1) m and -77.6 (95% CI -107.7 to -61) m, which exceeded the maximum allowable difference. Pain increased in the conventional walk test by 1.1 (SD 1.0) points, whereas pain increased in the app test by 0.8 (SD 1.4) points.

CONCLUSIONS

In individuals with persistent pain, the 2 methods of assessing the 6MWT may not be interchangeable due to limited validity. Potential reasons for the differences between the 2 methods might be attributed to the variation in track layout (shuttle track vs continuous circuit); poor GPS accuracy; deviations from the 30-m shuttle track; human variability in walking speed; and the potential impact of a first test on the second test due to fatigue, pain provocation, or a learning effect. Future research is needed to improve the accuracy of the GPS-based approach. Despite its limitations, the GPS-based 6MWT may still have value as a tool for remote monitoring that could allow individuals with persistent pain to self-administer frequent assessments of their functional capacity in their home environment.

Effects of cardiorespiratory rehabilitation program on submaximal exercise in patients with long-COVID-19 conditions: a systematic review of randomized controlled trials and recommendations for future studies

INTRODUCTION

Long-COVID-19 patients (LC19Ps) often experience cardiovascular and respiratory complications. Cardiorespiratory rehabilitation programs (CRRPs) have emerged as promising interventions to enhance exercise capacity in this population. This systematic review aimed to assess the impact of CRRPs on submaximal exercise performance, specifically the 6-minute walk test (6MWT) outcomes, in LC19Ps through an analysis of available randomized controlled trials (RCTs).

METHODS

A systematic search was conducted in PubMed/Medline and Scopus to identify relevant RCTs. Six RCTs meeting inclusion criteria were included in this review, investigating the effects of CRRPs on 6MWT outcomes in LC19Ps.

RESULTS

The findings from the included RCTs provide compelling evidence supporting the effectiveness of CRRPs in improving submaximal exercise performance in LC19Ps. These results underscore the potential of CRRPs to enhance submaximal exercise capacity and overall functional well-being in this population. However, future research is imperative to determine optimal CRRPs, including duration, intensity, and specific intervention components. Additionally, the long-term sustainability and durability of CRRP-induced improvements warrant further exploration. Future studies should prioritize patient-centric outcomes and address potential implementation barriers.

CONCLUSION

CRRPs show promise in ameliorating submaximal exercise performance among LC19Ps. Further research is needed to refine these programs and ensure their lasting impact on this patient group.

SYSTEMATIC REVIEW REGISTRATION

https://doi.org/10.17605/OSF.IO/HMN38. [Figure: see text].

Test-retest reliability, construct validity and determinants of 6-minute walk test performance in adult patients with asthma

INTRODUCTION AND OBJECTIVES

Current knowledge regarding the measurement properties of the 6-minute walk test (6MWT) in patients with asthma is limited. Therefore, the aim of this study was to assess the test-retest reliability, measurement error and construct validity of the 6MWT and identify determinants of 6-minute walk distance (6MWD) in patients with asthma.

PATIENTS AND METHODS

201 asthma patients referred for pre-pulmonary rehabilitation assessment, were retrospectively analyzed (age 61±12 years, 42% male, FEV1 78±27% predicted). Patients performed two 6MWTs on subsequent days using a 30 m straight walking course. Other measurements included resting dyspnea, maximal exercise capacity, body composition, pulmonary function, pulmonary and quadriceps muscle strength and symptoms of anxiety and depression. Measurement error (absolute reliability) was tested using standard error of measurement (SEM), minimal detectable change at 95% confidence interval (MDC95%) and Bland and Altman 95% limits of agreement, whereas test-retest reliability (relative reliability) and construct validity were assessed using the intra-class correlation coefficient (ICC2,1) and correlations, respectively.

RESULTS

The 6MWD showed excellent test-retest reliability (ICC2,1: 0.91). The mean change in 6MWD after the second 6MWT was 18m (95%CI 11-24m), with 73% of the patients walking further in the second test. The SEM and MDC95% for the 6MWT were 35 m and 98 m, respectively. The best 6MWD correlated strongly with peak oxygen uptake during CPET and resting dyspnea (r = 0.61-0.64) and had no-to-moderate correlations with body composition, pulmonary function, respiratory and quadriceps muscle strength and symptoms of anxiety and depression (r = 0.02-0.45). Multiple linear regression was able to identify maximal workload, BMI, rollator use, maximal expiratory pressure, FEV1 and DLCO as independent determinants of the best 6MWD (R2 = 0.58).

CONCLUSIONS

The 6MWT was considered to be reliable and valid in patients with asthma, which strengthens its clinical utility. However, the majority of patients demonstrated a considerable learning effect in the second 6MWT, providing a strong rationale for performing two 6MWTs.

Normative reference values and regression equations to predict the 6-minute walk distance in the Asian adult population aged 21-80 years

SUMMARY AT A GLANCE

The 6-min walk test (6MWT) is a widely used field walking test. This study reports the normative reference values (NRV) of distance walked during 6MWT (6MWD) in healthy Singaporeans (aged 21-80) and updates the 6MWD reference equations. This information may facilitate the interpretation of the 6MWD in clinical populations.

ETHICS APPROVAL

The Singapore Institute of Technology-Institutional Review Board (SIT-IRB Project Number: 2019099) approved this study to be carried out from June 2019 to January 2021. All participants gave written informed consent before data collection began.

BACKGROUND

The six-minute walk test (6MWT) is a widely adopted submaximal field-walking test to evaluate functional exercise capacity. This validated test is a reliable, safe, inexpensive, and straightforward assessment tool commonly used as an outcome measure, using the distance walked (6MWD) as the primary outcome. An earlier study has established the normative reference values (NRV) and equation in healthy Singaporeans - however, the small sample size and narrow age range curb adequate representation of the adult population profile.

OBJECTIVES

This study aims to update the NRV and reference equations to predict the distance walked during 6MWT (6MWD) for healthy Singaporeans aged 21-80.

METHODS

This cross-sectional study recruited community-dwelling healthy subjects aged 21-80 via convenience sampling. Each subject completed two trials of 6MWT according to the standard protocol. Primary outcome measures included 6MWD, pre-and post-test heart rate (HR), oxygen saturation, and blood pressure (BP).

RESULTS

172 healthy Singaporeans (females = 90 , males = 82 ) participated. The overall mean 6MWD was 578 . 00 ± 75 . 38 metres. The age-stratified mean 6MWD ranged from 601 . 3 ± 71 . 79 metres (aged 21-39) to 519 . 02 ± 55 . 42 metres (aged 60-80). Age, gender, and percentage maximum HR predicted (%PredHRmax) were the most significant variables (p < 0 . 001 ). 6MWD reference equation = 288 . 282 ( height , m )+ 27 . 463 × Gender ( male = 1 ; female = 0 )+ 4 . 349 ( % predHRmax )+ 1 . 191 (HR reserve, bpm) - 185 . 431 - 1 . 343 ( age , years )- 1 . 614 (weight, kg), R 2 = 58 % . Applying equations from other studies to the Singaporean population resulted in an overestimation of the 6MWD.

CONCLUSION

This study updated the NRV and reference equations of 6MWD for healthy Singaporeans aged between 21-80 years. This update revises the local benchmarks of 6MWD in Singapore, a widely adopted outcome measure.

Correlation Comparison and Personalized Utility of Field Walking Tests in Assessing the Exercise Capacity of Patients with Chronic Obstructive Pulmonary Disease: A Randomized Controlled Trial

Background: Incremental shuttle walking tests (ISWT) are regarded as valuable alternatives to 6-min walking tests (6MWT) and cardiopulmonary exercise tests (CPET) owing to the maximal and externally paced loading. This study investigated the validity and reliability of ISWT by analyzing the correlation of the distances of two field tests with peak oxygen consumption (VO2) of CPET in patients with COPD. Methods: In this randomized controlled trial, patients with COPD were enrolled from two hospitals. Three assessments were performed for all patients. The ISWT and 6MWT were repeated twice in Hospital 1 to assess reliability. Results: A total of 29 patients were enrolled. The distances of ISWT (0.782, p < 0.001) and 6MWT (0.512, p = 0.005) correlated with peak VO2. The intraclass correlation coefficients of both ISWT (0.988, p < 0.001) and 6MWT (0.959, p < 0.001) was high. Patients with higher peak VO2 walked a longer distance in ISWT than 6MWT (r = 0.590, p < 0.001). Conclusions: The ISWT more highly correlates with peak VO2 than the 6MWT and has excellent reliability in patients with COPD. According to peak VO2, the walking distances of each field test varied, suggesting that the application should be personalized for the exercise capacity.

Pulmonary rehabilitation for COPD: A narrative review and call for further implementation in Saudi Arabia

Chronic obstructive pulmonary disease (COPD) is a common, preventable, and treatable condition, in which outcomes can be improved with careful management. Pulmonary rehabilitation (PR) comprises exercise and education, delivered by multidisciplinary teams. PR is a cost-effective management strategy in COPD patients which improves exercise performance, reduces dyspnea, reduces the risk of exacerbation, and improves health-related quality of life. All COPD patients appear to benefit irrespective of their baseline function, and PR has also been shown to be a clinically and cost-effective management approach following an acute exacerbation. COPD patients with greater disability and those recovering postexacerbation should be specifically targeted for PR. Due to limited current capacity, the latter group may not currently be able to benefit from PR. Therefore, there is a need for the wider implementation of PR services in Saudi Arabia, requiring us to address challenges including capacity and workforce competency.

Reliability and validity of the Glittre-ADL test to assess the functional status of patients with interstitial lung disease

The study objective was to investigated the reliability and validity of the ADL-Glittre test (TGlittre) to assess the functional status of patients with interstitial lung disease (ILD). Twenty-one individuals with ILD participated (age: 63 ± 11 years; DLCO: 51.0 ± 12.6%predicted), evaluated with body plethysmography, Saint George Respiratory Questionnaire, modified Medical Research Council dyspnea scale, six-minute walk test (6MWT) and monitoring of physical activity of daily living. Two TGlittre were performed, with an interval of 30 minutes between them. The TGlittre demonstrated high test-retest reliability, with an intraclass correlation coefficient of 0.90 (95%CI: 0.75-0.96; p < 0.001). Nineteen patients (90.5%) performed better on the second test (mean difference between TGlittre 1 and 2: -0.57 ± 0.96 minute; p = 0.001), with a learning effect of 11.6%. The time in TGlittre correlated with 6MWT (r = -0.70; p = 0.002) and with the total energy expenditure in physical activity of daily living (r = -0.52; p = 0.02). In %predicted, TGlittre and 6MWT also correlated (r = -0.50; p = 0.04). Correlations were observed between TGlittre and pulmonary function variables (r = -0.47 to -0.57; p = 0.01 to p = 0.04). There was no difference in the physiological response between TGlittre 1 and 2, and between TGlittre and 6MWT (p > 0.05). In conclusion, the TGlittre is reliable and valid for assessing functional status of patients with ILD.

Reference Value for the Distance Walked in the Six-Minute Walk Test in Obese Brazilian Men in the Preoperative Period of Bariatric Surgery

BACKGROUND

Obesity has several effects on the mechanics of the rib cage that may impair the exercise performance of obese individuals and therefore impact the assessment of surgical risk. This study aimed to establish a reference value for the 6-minute walk distance (6 MWD) in obese Brazilian men in the preoperative period of bariatric surgery that considers the effect of lung function.

METHODS

This was a cross-sectional study in which 104 obese men underwent the six-minute walk test (6 MWT) before bariatric surgery. They also underwent the spirometry test and respiratory muscle strength measurement before the 6 MWT.

RESULTS

The 6 MWD was correlated with age (r = -0.388, p=0.0005), weight (r = -0.365, p=0.0007), height (r = 0.285, p=0.022), body mass index (BMI) (r = -0.543, p < 0.0001), forced vital capacity (FVC) (r = 0.472, p < 0.0001), peak expiratory flow (r = 0.253, p=0.031), and maximal inspiratory pressure (r = 0.313, p=0.017). In the stepwise forward regression analysis, BMI, FVC, and age were the only variables that independently predicted the 6 MWD and explained 40% of its variability. The reference equation proposed for obese Brazilian men is 6 MWD (m) = 570.5 - (3.984 × BMI_kg/m2) + (1.093 × FVC_%predicted) - (0.836 × age_yrs).

CONCLUSION

In this sample of obese Brazilian men, lung function contributed to poor performance in the 6 MWT. In these individuals, BMI, FVC, and age were the variables that composed the reference equation for the 6 MWD. Thus, in several clinical settings, such as in the evaluation before bariatric surgery, pulmonary function data are important to determine the reference value for the 6 MWD.

Characterizing Practice Effects in Performance-Based Tests Administered to Users of Unilateral Lower Limb Prostheses: A Preliminary Study

BACKGROUND

Performance-based tests are viewed as a gold standard for measuring physical capability. Practice effects, however, may threaten their predictive, discriminative, and evaluative applications. Despite these potential consequences, practice effects have received limited attention in users of lower limb prostheses (LLP).

OBJECTIVE

To perform an initial characterization of the occurrence, time-course, and magnitude of practice effects in three performance-based tests administered to users of LLP.

DESIGN

Secondary analysis of data from a multisite repeated-measures study.

SETTING

Outpatient clinic and research laboratory.

PARTICIPANTS

Convenience sample of established ambulatory users of unilateral transtibial and transfemoral prostheses (n = 60).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Practice effects were identified as significant changes in slope of participants' cumulative trial-by-trial records. The occurrence, time-course, and magnitude of practice effects were computed for the Timed Up and Go (TUG), Four Square Step Test (FSST), and the 10-m Walk Test (10mWT).

RESULTS

Across tests, practice effects were observed in 45% to 76% of participants. The proportion of participants with practice effects (ie, occurrence) was significantly greater for the FSST than the 10mWT (P = .008). The median number of trials (ie, time-course) required for participants to reach a consistent level of performance was not significantly different between tests (FSST: 4 trials, TUG: 4 trials; 10mWT: 3.5 trials; P = .481). Practice effect magnitude (ie, difference between the mean of trials during the plateau and best performance over the first two trials) was significantly greater than zero for the FSST (1.6 s; 16%) and TUG (1.4 s; 13%) (P < .05).

CONCLUSION

Results indicate that the FSST, TUG, and 10mWT were susceptible to practice effects in this sample of users of LLP. Practice effects may obscure significant differences in walking and balance ability, and thereby, in the absence of modifications, limit the use of these tests for making individual patient clinical decisions and analyzing group-level data.

Respiratory rehabilitation techniques used for the treatment of COPD patients

Introduction. Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality throughout the world. At present, the pharmacological therapy is not enough for a patient with COPD in regard to heath status and exercise tolerance. It requires additional therapies aimed to improve the quality of life, delay the lung function decline, increase exercise capacity, and reduce the respiratory symptoms and the number of exacerbations. Pulmonary rehabilitation program (PRP) has been shown to improve respiratory muscle, to optimize functional, psychosocial, behavioral and nutritional status. The aim of the present study was to asses the impact of PRP on COPD patients, focusing on the clinical benefits of PRP, which may further provide to the patients a good support for change. Material and method. Sixty-seven patients with clinically stable COPD were enrolled in this prospective study, consisting in a 6-weeks of PRP. There were recorded demographic data, smoking and medical history, and abnormal findings at the physical examination. All patients completed CAT (COPD Assessment Test) questionnaire and dyspnea on Borg scale, they performed spirometry, and six minutes walking test (6MWT), before and after the completion of the rehabilitation program. Results and Discussions. After the 6-week period of PRP, a large proportion of patients presented higher values of spirometric parameters, although the change was no statistically significant. The impact of COPD on the patient’s health was significantly improved, 58.2% of patients registered < 10 points of CAT questionnaire after PRP (p<0.05). 75% of patients reported a 0-5 points of dyspnea on Borg scale comparing with 29% before the PRP (p=0.0147), and 56% a 0-5 points of fatigue while only 25% of patients had the same score before the rehabilitation programme (p=0,022). Only 8 patients (11.94% vs 31.34%, p<0.05) reported a SaO2 lower than 90% after the PRP. The 6MWD was longer than 250m at the end of the 6-weeks of PRP for 38 patients (56.7% vs 22.38%, p<0.05). Conclusions. The present study showed that a PRP added to pharmacological treatment had a beneficial role of increasing the patient’ health status and exercise tolerance for COPD patients.

Six-Minute Walk Test: Clinical Role, Technique, Coding, and Reimbursement

The 6-min walk test (6MWT) is a commonly used test for the objective assessment of functional exercise capacity for the management of patients with moderate-to-severe pulmonary disease. Unlike pulmonary function testing, the 6MWT captures the often coexisting extrapulmonary manifestations of chronic respiratory disease, including cardiovascular disease, frailty, sarcopenia, and cancer. In contrast with cardiopulmonary exercise stress testing, this test does not require complex equipment or technical expertise. In this low complexity, safe test, the patient is asked to walk as far as possible along a 30-m minimally trafficked corridor for a period of 6 min with the primary outcome measure being the 6-min walk distance (6MWD) measured in meters. There has been interest in other derived indexes, such as distance-desaturation product (the product of nadir oxygen saturation and walk distance), which in small studies has been predictive of morbidity and mortality in certain chronic respiratory conditions. Special attention to methodology is required to produce reliable and reproducible results. Factors that can affect walk distance include track layout (continuous vs straight), track length, oxygen amount and portability, learning effect, and verbal encouragement. The absolute 6MWD and change in 6MWD are predictive of morbidity and mortality in patients with COPD, pulmonary arterial hypertension, and idiopathic pulmonary fibrosis and patients awaiting lung transplant, highlighting its use in management decisions and clinical trials. As of January 2018, Current Procedural Terminology code 94620 (simple pulmonary stress test) has been deleted and replaced by two new codes, 94617 and 94618. Code 94617 includes exercise test for bronchospasm including pre- and postspirometry, ECG recordings, and pulse oximetry. Code 94618, pulmonary stress testing (eg, 6MWT), includes the measurement of heart rate, oximetry, and oxygen titration when performed. If 94620 is billed after January 2018 it will not be reimbursed.

Repeated Use of 6-min Walk Test with Immediate Knowledge of Results for Walking Capacity in Chronic Stroke: Clinical Trial of Fast versus Slow Walkers

AIM

This study aimed to determine the effects of repeated use of the 6-minute walk test (6MWT) with immediate knowledge of results (KR) on the walking capacity by comparing fast and slow walkers in patients with chronic hemiparesis.

METHODS

Twenty-five subjects were allocated to 2 groups depending on their walking speed¹: Group 1 (fast walkers, n₁ = 11): greater than equal to .8 m/s and² Group 2 (slow walkers, n₂ = 14): less than .8 m/s. All subjects underwent the 6MWT once a day, 5 days a week, for 4 weeks (a total of 20 sessions). The 6MWT was performed on a 30-m path with immediate KR; subjects informed the time taken to walk each 30-m path. Outcome measures included the 6MWT and 10-meter walk test (10MWT). Measurements were taken before and after 4 weeks. Results of within-group comparisons showed significant improvements in the 10MWT and 6MWT for both groups pre- and post-test (P < .05). Furthermore, in between-group comparison, results of Group 1 differences were greater between pre- and post-test in the 10MWT and 6MWT values as compared to Group 2 (P < .05). These findings indicate that repeated use of the 6MWT with immediate KR may be beneficial to enhance walking capacity in patients with chronic stroke, with more favorable changes in better poststroke walking speed.

Practice effect and cueing of 2-minute walk test, 6-minute walk test and 10-meter walk test in frail older adults with and without dementia - Recommendations to walk tests protocols

OBJECTIVES

1) To determine if there was a practice effect associated with walk tests performed by frail older adults with and without dementia, 2) to examine the role of systematic cueing in the walk tests for those with dementia, and 3) to make recommendations to testing protocols of the walk tests for frail older adults with and without dementia.

SETTING

Residential and day care facilities.

PARTICIPANTS

44 frail older adults with normal cognition (NON-DEM) and 39 older adults with Alzheimer's disease or dementia (DEM) who were able to walk independently for at least 15 m.

METHODS

All the participants completed multiple trials of 2-minute walk test (2MWT), 6-minute walk test (6MWT) and 10-meter walk test (10MeWT) on three separate testing occasions. The DEM group was facilitated to complete the walk tests using a progressive cueing system.

RESULTS

Significant increases in the walking performance within the same testing occasion were found in the 2MWT (NON-DEM: p = .002; DEM: p ≤ .044) and 6MWT (NON-DEM: p ≤ .004; DEM: p ≤ .002) for both groups but only in the 10MeWT (p ≤ .023) for the DEM group. Significant increases in the walking performance across testing occasions were shown in the 2MWT (p ≤ .047), 6MWT (p ≤ .005) and 10MeWT (p ≤ .039) for the NON-DEM group but not the DEM group (all p > .05). Multivariate regression analyses showed that the cognitive function of the DEM group was independently and inversely associated with the level of cueing provided during the walk tests (p ≤ .007).

CONCLUSION

Practice effect associated with the walk tests was found within and across testing occasions for frail older adults with normal cognition, and only within the same testing occasion for those with dementia. Systematic cueing should be provided for those with dementia to complete the walk tests. Testing protocols of the walk tests have been recommended for these two population groups.

Intra- and inter-rater reproducibility of the 6-minute walk test and the 30-second sit-to-stand test in patients with severe and very severe COPD

Background

In patients with COPD, the 6-minute walk test (6MWT) and the 30-second sit-to-stand test (30sec-STS) are widely used as clinical outcome measures of walking capacity, lower limb muscle strength, and functional ability. Due to a documented learning effect, at least two trials are recommended for assessment. The aim of our study was to investigate the intra- and inter-rater reliability and agreement of the two tests in patients with severe and very severe COPD (FEV₁ <50%).

Patients and methods

Fifty patients (22 females; mean [SD]: age 67 [9] years, FEV₁ predicted 32 [9]%) were assessed with the 6MWT and the 30sec-STS twice by the same assessor on test-day 1 (T1) and by another assessor 7–10 days later on test-day 2 (T2).

Results

The 6MWT intra- and inter-rater reliability (intraclass correlation coefficient, ICC_1.1) was 0.98 (lower limit 95% CI: 0.94) and 0.96 (lower limit 95% CI: 0.94), respectively, and agreement (standard error of the measurement, SEM) was 14.8 and 20.5 m, respectively. The 30sec-STS intra- and inter-rater reliability and agreement results were, respectively, ICC_1.1 0.94 (lower limit 95% CI: 0.90) and 0.92 (lower limit 95% CI: 0.86), with SEM of 0.97 and 1.14 repetitions. There was no difference (95% CI: −5.3; 8.1) between the 6MWT distances on T1, while the mean walking distance improved 7.9 m (0.0 m; 15.8 m) from T1 to T2. Improvement on the same test date was less likely (OR: 3.6 [95% CI: 1.1; 11.8], Fisher’s exact test, P=0.047) in patients who walked less than 350 m in the 6MWT. We found no clinically relevant learning effect in the 30sec-STS.

Conclusion

In patients with severe and very severe COPD the 6MWT and the 30sec-STS showed excellent intra- and inter-rater reliability and acceptable agreement. No learning effect was documented for the tests when performed on the same day. Our data suggest that in clinical practice using different assessors is acceptable, and that a single test trial may be sufficient to assess patients with severe and very severe COPD.

Is there a learning effect when the 6-minute walk test is repeated in people with suspected pulmonary hypertension?

The aim of the study was to determine if there was a difference in 6-minute walk distance (6MWD) when two 6-minute walk tests (6MWTs) were performed at the initial assessment prior to attendance at the pulmonary hypertension (PH) clinic and at the 6-month follow-up. Two 6MWTs were performed at both visits on a 32-m continuous track in the physiotherapy hospital outpatient setting using standard instructions and encouragement. Two hundred and fourteen participants completed two 6MWTs at the initial assessment and 71 participants at the 6-month follow-up (mean (standard deviation) age: 57 (16) years; body mass index: 27 (6) kg/m²). Using the better 6MWT, the mean distances walked were 429 (136) and 447 (130) m, respectively. There was a significant increase in 6MWD when a second 6MWT was performed at initial assessment (mean difference [95% confidence interval (CI)]: 19 m (14–24), p < 0.001) and at the follow-up (mean difference [95% CI]: 19 m (10–27), p < 0.001) but not in those who walked <300 m at the initial assessment (mean difference [95% CI]: 9 m (−5 to 22), p = 0.208). There were no adverse events during testing. Prior to attendance at the PH Clinic when people are asked to perform the 6MWT for the first time and at the 6-month follow-up, two walk tests should be performed in order to eliminate a learning effect and to ensure accuracy of measurement.

Current best practice in rehabilitation in interstitial lung disease

Interstitial lung disease (ILD) is a group of chronic respiratory diseases characterized by dyspnoea on exertion and decline in health-related quality of life (HRQL). People with ILD experience significant exercise limitation with contributors that include ventilatory limitation, impaired gas exchange, decreased cardiac function and skeletal muscle dysfunction. Pulmonary rehabilitation (PR) is well established in patients with chronic obstructive pulmonary disease (COPD) as a means to overcome exercise limitation and improve activity-related dyspnoea. There is increasing evidence for similar effects of PR in people with ILD. This review discusses the evidence for PR in ILD, outlines the essential components of PR in this population, and highlights special considerations for exercise training in people with ILD. Possible future directions for PR research in people with ILD are explored.

Criterion validity and reliability of a smartphone delivered sub-maximal fitness test for people with type 2 diabetes

Background

Prevention of multi-morbidities following non-communicable diseases requires a systematic registration of adverse modifiable risk factors, including low physical fitness. The aim of the study was to establish criterion validity and reliability of a smartphone app (InterWalk) delivered fitness test in patients with type 2 diabetes.

Methods

Patients with type 2 diabetes (N = 27, mean (SD) age 64.2 (5.9) years, BMI 30.0 (5.1) kg/m², (30 % male)) completed a 7-min progressive walking protocol twice (with and without encouragement). VO₂ during the test was assessed using indirect calorimetry and the acceleration (vector magnitude) from the smartphone was obtained. The vector magnitude was used to predict VO_2peak along with the co-variates weight, height and sex. The validity of the algorithm was tested when the smartphone was placed in the right pocket of the pants or jacket. The algorithm was validated using leave-one-out cross validation. Test-retest reliability was tested in a subset of participants (N = 10).

Results

The overall VO_2peak prediction of the algorithm (R²) was 0.60 and 0.45 when the smartphone was placed in the pockets of the pants and jacket, respectively (p < 0.001). The mean bias (limits of agreement) in the cross validation was−0.4 (38) % (pants) and−0.1 (46) % (jacket). When the smartphone was placed in the jacket a significant intensity dependent bias (r = 0.5, p = 0.02) was observed. The test-retest intraclass correlations were 0.85 and 0.86 (p < 0.001), for the pants and jacket, respectively. No effects of encouragement were observed on test performance.

Conclusion

In conclusion, the InterWalk Fitness Test is accurate and reliable for persons with type 2 diabetes when the smartphone is placed in the side pocket of the pants for. The test could give a fair estimate of the CRF in absence of a progressive maximal test during standardized conditions with the appropriate equipment.

Trial registration

www.clinicaltrials.org (NCT02089477), first registered (prospectively) on March 14th 2014

Community-based pulmonary rehabilitation in a non-healthcare facility is feasible and effective

Pulmonary rehabilitation programs (PRPs) are most commonly provided in hospital settings which present barriers to attendance such as long distances or travel times. Community-based settings have been used in an attempt to alleviate the travel burden. This study evaluated the feasibility and outcomes of a network of community-based PRPs provided in non-healthcare facilities (CPRPs). The CPRPs were established in five venues and comprised two supervised group sessions each week for 8 weeks. Participant inclusion criteria and guidelines for exercise testing and training were developed to reduce the risk of adverse events. Outcome measures included 6-min walk distance (6MWD) and health-related quality of life (chronic respiratory questionnaire (CRQ)). Respiratory-related hospital admission data were collected in the 12 months prior to and following the program. Two hundred and fifty-one participants (79% with chronic obstructive pulmonary disease: mean ± SD FEV₁ 49 ± 21%predicted) entered a CPRP of which 166 (66%) completed. Improvements were demonstrated in 6MWD (mean difference (95% CI) 44 m (37-52)) and total CRQ score (0.5 points per item (0.4-0.7)). Fewer participants had a respiratory-related hospital admission following the program (12% vs. 37%, p < 0.0001). Pulmonary rehabilitation is safe, feasible and effective when conducted in community-based non-healthcare facilities.

Comparison of the six-minute walk test with a cycle-based cardiopulmonary exercise test in people following curative intent treatment for non-small cell lung cancer

This study is aimed to (i) compare both the magnitude of impairment in exercise capacity and exercise responses measured during the six-minute walk test (6MWT) and the cardiopulmonary exercise test (CPET) and (ii) investigate the effect of test repetition on six-minute walk distance (6MWD) in people following curative intent treatment for non-small cell lung cancer (NSCLC). Twenty participants (67 ± 10 years; 14 females), 6-10 weeks following lobectomy, underwent a CPET and two 6MWTs. Peak exercise responses, dyspnoea and leg fatigue, as well as heart rate (HR) and oxygen saturation (SpO2) during the 6MWT, were compared to those during the CPET. Compared with exercise capacity when expressed as peak rate of oxygen consumption (%pred) measured during the CPET, exercise capacity when expressed as 6MWD (%pred) was less impaired (81 ± 10 vs. 63 ± 15 %pred; p < 0.001). Compared with the CPET, the 6MWT elicited lower peak HR (119 ± 15 vs. 128 ± 18 beats minute(-1); p = 0.02), lower SpO2 (93 ± 2 vs. 95 ± 3%; p < 0.05), less dyspnoea (3.1 ± 1.6 vs. 6.9 ± 2.6; p < 0.01) and less leg fatigue (2.0 ± 1.9 vs. 6.8 ± 2.4; p < 0.01). The 6MWD increased 19 ± 19 metre (4 ± 4%) with test repetition (p < 0.001). In people following curative intent treatment for NSCLC, the 6MWT appears to elicit sub-maximal exercise responses when compared with the CPET. There is a significant effect of test repetition on 6MWD.

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.

Exercise Induces Peripheral Muscle But Not Cardiac Adaptations After Stroke: A Randomized Controlled Pilot Trial

Objective

To explore the physiological factors affecting exercise-induced changes in peak oxygen consumption and function poststroke.

Design

Single-center, single-blind, randomized controlled pilot trial.

Setting

Community stroke services.

Participants

Adults (N=40; age>50y; independent with/without stick) with stroke (diagnosed >6mo previously) were recruited from 117 eligible participants. Twenty participants were randomized to the intervention group and 20 to the control group. No dropouts or adverse events were reported.

Interventions

Intervention group: 19-week (3times/wk) progressive mixed (aerobic/strength/balance/flexibility) community group exercise program. Control group: Matched duration home stretching program.

Main Outcome Measures

(1) Pre- and postintervention: maximal cardiopulmonary exercise testing with noninvasive (bioreactance) cardiac output measurements; and (2) functional outcome measures: 6-minute walk test; timed Up and Go test, and Berg Balance Scale.

Results

Exercise improved peak oxygen consumption (18±5 to 21±5mL/(kg⋅min); P<.01) and peak arterial-venous oxygen difference (9.2±2.7 to 11.4±2.9mL of O₂/100mL of blood; P<.01), but did not alter cardiac output (17.2±4 to 17.7±4.2L/min; P=.44) or cardiac power output (4.8±1.3 to 5.0±1.35W; P=.45). A significant relation existed between change in peak oxygen consumption and change in peak arterial-venous oxygen difference (r=.507; P<.05), but not with cardiac output. Change in peak oxygen consumption did not strongly correlate with change in function.

Conclusions

Exercise induced peripheral muscle, but not cardiac output, adaptations after stroke. Implications for stroke clinical care should be explored further in a broader cohort.

Comparison of exercise capacity in COPD and other etiologies of chronic respiratory failure requiring non-invasive mechanical ventilation at home: retrospective analysis of 1-year follow-up

INTRODUCTION

The objective of this study was to compare the change in 6-minute walking distance (6MWD) in 1 year as an indicator of exercise capacity among patients undergoing home non-invasive mechanical ventilation (NIMV) due to chronic hypercapnic respiratory failure (CHRF) caused by different etiologies.

METHODS

This retrospective cohort study was conducted in a tertiary pulmonary disease hospital in patients who had completed 1-year follow-up under home NIMV because of CHRF with different etiologies (ie, chronic obstructive pulmonary disease [COPD], obesity hypoventilation syndrome [OHS], kyphoscoliosis [KS], and diffuse parenchymal lung disease [DPLD]), between January 2011 and January 2012. The results of arterial blood gas (ABG) analyses and spirometry, and 6MWD measurements with 12-month interval were recorded from the patient files, in addition to demographics, comorbidities, and body mass indices. The groups were compared in terms of 6MWD via analysis of variance (ANOVA) and multiple linear regression (MLR) analysis (independent variables: analysis age, sex, baseline 6MWD, baseline forced expiratory volume in 1 second, and baseline partial carbon dioxide pressure, in reference to COPD group).

RESULTS

A total of 105 patients with a mean age (± standard deviation) of 61±12 years of whom 37 had COPD, 34 had OHS, 20 had KS, and 14 had DPLD were included in statistical analysis. There were no significant differences between groups in the baseline and delta values of ABG and spirometry findings. Both univariate ANOVA and MLR showed that the OHS group had the lowest baseline 6MWD and the highest decrease in 1 year (linear regression coefficient -24.48; 95% CI -48.74 to -0.21, P=0.048); while the KS group had the best baseline values and the biggest improvement under home NIMV (linear regression coefficient 26.94; 95% CI -3.79 to 57.66, P=0.085).

CONCLUSION

The 6MWD measurements revealed improvement in exercise capacity test in CHRF patients receiving home NIMV treatment on long-term depends on etiological diagnoses.

Mucociliary clearance techniques for treating non-cystic fibrosis bronchiectasis: Is there evidence?

Non-cystic fibrosis bronchiectasis (nCFb) is an acquired condition of variable etiology. An impaired mucociliary clearance seems to be one of the mechanisms behind nCFb, and treatment involves antibiotics, mucoactive agents, and airway clearance techniques (ACTs). Traditional ACTs have four components: postural drainage, percussion, vibration of the chest wall, and coughing. Reviewing the international medical literature on the use of ACTs for patients with nCFb from 1989 to the present day, we retrieved 93 articles, of which 35 met our selection criteria for this analysis. We reviewed active cycle of breathing techniques (ACBT), forced expiration techniques (FET), autogenic drainage, postural drainage, oscillating positive expiratory pressure (OPep), high frequency chest wall oscillation (HFCWO), and exercise or pulmonary rehabilitation. Overall, ACTs appear to be safe for individuals (adults and children) with stable bronchiectasis; where there may be improvements in sputum expectoration, selected measures of lung function, and health-related quality of life. Unfortunately, there is a lack of RCTs in nCFb patients, especially in children. Moreover, none of the studies describes long-term effects of ACTs. It should be noted that a single intervention might not reflect the longer-term outcome and there is no evidence to recommend or contest any type of ACTs in nCFb management. Multicenter RCTs are necessary to evaluate the different techniques of ACTs especially in children with nCFb.

Reproducibility of the six-minute walk test and Glittre ADL-test in patients hospitalized for acute and exacerbated chronic lung disease

Background:

The 6-minute walk test (6MWT) and the Glittre ADL-test (GT) are used to assess functional capacity and exercise tolerance; however, the reproducibility of these tests needs further study in patients with acute lung diseases.

Objectives:

The aim of this study was to investigate the reproducibility of the 6MWT and GT performed in patients hospitalized for acute and exacerbated chronic lung diseases.

Method:

48 h after hospitalization, 81 patients (50 males, age: 52±18 years, FEV₁: 58±20% of the predicted value) performed two 6MWTs and two GTs in random order on different days.

Results:

There was no difference between the first and second 6MWT (median 349 m [284-419] and 363 m [288-432], respectively) (ICC: 0.97; P<0.0001). A difference between the first and second tests was found in GT (median 286 s [220-378] and 244 s [197-323] respectively; P<0.001) (ICC: 0.91; P<0.0001).

Conclusion:

Although both the 6MWT and GT were reproducible, the best results occurred in the second test, demonstrating a learning effect. These results indicate that at least two tests are necessary to obtain reliable assessments.

Reliability and validity of an arabic version of the dyspnea-12 questionnaire for Saudi nationals with chronic obstructive pulmonary disease

BACKGROUND:

Dyspnea is a distressing symptom experienced by people with chronic obstructive pulmonary disease (COPD). The dyspnea-12 (D-12) questionnaire comprises of 12 items and assesses the quality of this symptom, its severity and the emotional response. The original (English) version of the D-12 is reliable and valid for the measurement of dyspnea in pulmonary diseases.

AIM:

To translate the D-12 into Arabic and determine whether this version is reliable and valid in Saudi nationals with COPD.

METHODS:

The D-12 was translated into Arabic version and reviewed by an expert panel before being back-translated into English. The Arabic version was administered to five patients with COPD to test whether it was easily understood after which a final Arabic version was produced. Thereafter, 40 patients with COPD (aged 63 ΁ 9 years; 33 [82.5%] males; forced expiratory volume in one second (FEV ₁) 47 ΁ 16% predicted) completed the D-12, the COPD Assessment Test (CAT) and the Chronic Respiratory Disease Questionnaire (CRDQ). Lung function and 6-minute walk distance were also measured. The D-12 was re-administered two weeks later.

RESULTS:

The Arabic version of the D-12 demonstrated good reliability over the two administration (intraclass correlation coefficient = 0.94, P = 0.01). Strong associations were demonstrated between the (1) total score for the D-12 and the CAT, (2) quality sub-score of the D-12 and the CAT and (3) emotional response sub-score of the D-12 and emotional function domain of the CRDQ (r ≥ 0.6, all P < 0.01).

CONCLUSION:

The Arabic version of the D-12 is a reliable and valid instrument in Saudi nationals with COPD.

Comparison of laboratory- and field-based exercise tests for COPD: a systematic review

Exercise tests are often used to evaluate the functional status of patients with COPD. However, to the best of our knowledge, a comprehensive systematic comparison of these tests has not been performed. We systematically reviewed studies reporting the repeatability and/or reproducibility of these tests, and studies comparing their sensitivity to therapeutic intervention. A systematic review identified primary manuscripts in English reporting relevant data on the following exercise tests: 6-minute walk test (6MWT) and 12-minute walk test, incremental and endurance shuttle walk tests (ISWT and ESWT, respectively), incremental and endurance cycle ergometer tests, and incremental and endurance treadmill tests. We identified 71 relevant studies. Good repeatability (for the 6MWT and ESWT) and reproducibility (for the 6MWT, 12-minute walk test, ISWT, ESWT, and incremental cycle ergometer test) were reported by most studies assessing these tests, providing patients were familiarized with them beforehand. The 6MWT, ISWT, and particularly the ESWT were reported to be sensitive to therapeutic intervention. Protocol variations (eg, track layout or supplemental oxygen use) affected performance significantly in several studies. This review shows that while the validity of several tests has been established, for others further study is required. Future work will assess the link between these tests, physiological mechanisms, and patient-reported measures.

Investigation of the immediate pre-operative physical capacity of patients scheduled for elective abdominal surgery using the 6-minute walk test

OBJECTIVES

To evaluate the effects of repetition of the 6-minute walk test in patients scheduled to undergo abdominal surgery within the next 48 hours, and to verify the physical capacity of these subjects before surgery.

DESIGN

Cross-sectional study.

SETTING

University teaching hospital.

PARTICIPANTS

Forty-two patients scheduled for elective abdominal surgery within the next 48 hours.

OUTCOME MEASURES

Distance walked in the 6-minute walk test, heart rate, peripheral oxygen saturation, dyspnoea and leg fatigue.

RESULTS

Thirty-one patients (74%) were able to walk for a longer distance when the test was repeated. In these subjects, the mean increase in distance walked was 35.4 [standard deviation (SD) 19.9]m. Heart rate, dyspnoea and leg fatigue increased significantly over time on both tests (P<0.05). The mean heart rate at the end of the sixth minute was significantly higher on the second test (P=0.022). Peripheral oxygen saturation remained above 90% in both tests. The furthest distance walked was, on average, 461.3 (SD 89.7)m. This value was significantly lower than that predicted for the sample (P<0.001).

CONCLUSION

Patients scheduled to undergo abdominal surgery were able to walk further when they performed a second 6-minute walk test. Moreover, they showed reduced physical ability before surgery. These findings suggest that repetition of the 6-minute walk test may increase the accuracy of the distance walked, which is useful for studies assessing the physical capacity of patients undergoing abdominal surgery.

Pulmonary rehabilitation and noninvasive ventilation in patients with hypercapnic interstitial lung disease

BACKGROUND

Pulmonary rehabilitation (PR) has a positive impact on functional status and quality of life in patients with interstitial lung disease (ILD).

OBJECTIVES

This study investigated the effects of PR in hypercapnic ILD patients receiving nighttime noninvasive positive pressure ventilation (NPPV).

METHODS

Consecutive ILD patients referred to a specialized inpatient PR center were included. All participated in a PR program. Those with hypercapnia received NPPV (NPPV group; n = 29); the remaining patients served as comparison group (n = 319).

RESULTS

PR improved the 6-min walk distance by 64.4 ± 67.1 m versus baseline (p < 0.0001) in NPPV patients and by 43.2 ± 55.1 m (p < 0.0001) in the comparison group (difference 21.1 m, 95% confidence interval 0.5-41.8; p = 0.045). There was no change in total lung capacity during PR in NPPV recipients or the comparison group. Forced vital capacity significantly increased from baseline in the comparison, but not the NPPV group. NPPV recipients were significantly more likely than the comparison group to have improved dyspnea during PR (p = 0.049). There was no improvement in the 36-item Short Form (SF-36) physical component score in the NPPV group after PR, but there was in the comparison group. PR improved the SF-36 mental component score versus baseline in both groups.

CONCLUSION

An individually tailored PR plus nighttime NPPV appears feasible in hypercapnic ILD patients and significantly improves exercise capacity and quality of life.

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.

Minimal important difference in field walking tests in non-cystic fibrosis bronchiectasis following exercise training

BACKGROUND

The 6-min walk distance (6MWD) and incremental shuttle walk distance (ISWD) are clinically meaningful measures of exercise capacity in people with non-cystic fibrosis (CF) bronchiectasis, but the change in walking distance which constitutes clinical benefit is undefined. This study aimed to determine the minimal important difference for the 6MWD and ISWD in non-CF bronchiectasis.

METHODS

Thirty-seven participants with mean FEV1 70% predicted completed both field walking tests before and after an 8-week exercise program. The minimal important difference was calculated using a distribution-based and anchor-based method, with the global rating of change scale used.

RESULTS

The mean change in 6MWD in participants who reported themselves to be unchanged was 10 m, compared to 36 m (small change) and 45 m (substantial change) (p = 0.01). For the ISWD, the mean change in participants who reported themselves to be unchanged was 33 m, compared to 54 m (small change) and 73 m (substantial change) (p = 0.04). The anchor-based method defined the minimal important difference for 6MWD as 24.5 m (AUC 0.76, 95% CI 0.61-0.91) and for ISWD as 35 m (AUC 0.88, 95% CI 0.73-0.99), based on participant's global rating of change. The distribution-based method indicated a value of 22.3 m for the 6MWD and 37 m for the ISWD. There was excellent agreement between the two methods for the 6MWD (kappa = 0.91) and the ISWD (kappa = 0.92).

CONCLUSIONS

Small changes in 6MWD and ISWD may represent clinically important benefits in people with non-CF bronchiectasis. These data are likely to assist in the interpretation of change in exercise capacity following intervention.

Is there an association between postural balance and pulmonary function in adults with asthma?

OBJECTIVE

Asthma may cause systemic repercussions due to its severity and the effects of treatment. Our objective was to compare posture, balance, functional capacity, and quality of life (QOL) according to the severity of disease, as assessed by pulmonary function levels.

METHOD

This cross-sectional study evaluated fifty individuals with asthma. We compared two groups of adult individuals who were divided according to the median of the forced expiratory volume in one second (FEV1) as follows: group A  =  FEV1>74% predicted; group B  =  FEV1<74% predicted. All patients underwent the following tests: spirometry, whole-body plethysmography, diffusing capacity for carbon monoxide (DLco), respiratory muscle strength, posture assessment, stabilometry, six-minute walking distance (6MWD), and QOL.

RESULTS

All pulmonary function variables exhibited statistically significant differences between the two groups, except for the DLco. The maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and 6MWD were lower in group B. The maximal mediolateral velocity and the mediolateral displacement were significantly different, while the postural changes and QOL were similar between the groups.

CONCLUSIONS

In adult individuals with asthma, the pulmonary function is associated with balance control in the mediolateral direction but does not influence the postural changes or QOL.

Optimizing the 6-min walk test as a measure of exercise capacity in COPD

BACKGROUND

It is uncertain whether the effort and expense of performing a second walk for the 6-min walk test improves test performance. Hence, we attempted to quantify the improvement in 6-min walk distance if an additional walk were to be performed.

METHODS

We studied patients consecutively enrolled into the National Emphysema Treatment Trial who prior to randomization and after 6 to 10 weeks of pulmonary rehabilitation performed two 6-min walks on consecutive days (N = 396). Patients also performed two 6-min walks at 6-month follow-up after randomization to lung volume reduction surgery (n = 74) or optimal medical therapy (n = 64). We compared change in the first walk distance to change in the second, average-of-two, and best-of-two walk distances.

RESULTS

Compared with the change in the first walk distance, change in the average-of-two and best-of-two walk distances had better validity and precision. Specifically, 6 months after randomization to lung volume reduction surgery, changes in the average-of-two (r = 0.66 vs r = 0.58, P = .01) and best-of-two walk distances (r = 0.67 vs r = 0.58, P = .04) better correlated with the change in maximal exercise capacity (ie, better validity). Additionally, the variance of change was 14% to 25% less for the average-of-two walk distances and 14% to 33% less for the best-of-two walk distances than the variance of change in the single walk distance, indicating better precision.

CONCLUSIONS

Adding a second walk to the 6-min walk test significantly improves its performance in measuring response to a therapeutic intervention, improves the validity of COPD clinical trials, and would result in a 14% to 33% reduction in sample size requirements. Hence, it should be strongly considered by clinicians and researchers as an outcome measure for therapeutic interventions in patients with COPD.

State of the art: how to set up a pulmonary rehabilitation program

Pulmonary rehabilitation plays an essential role in the management of symptomatic patients with COPD. The benefits of rehabilitation include a decrease in dyspnoea and fatigue, and improvements in exercise tolerance and health-related quality of life. Importantly, rehabilitation reduces hospitalization for acute exacerbations and is cost-effective. Although most of the evidence for pulmonary rehabilitation has been obtained in patients with COPD, symptomatic individuals with other respiratory diseases have been shown to benefit. In this review we outline a stepwise approach to establish, deliver and evaluate a pulmonary rehabilitation program (PRP) that would be feasible in most settings. Throughout the review we have specified the minimum requirements for a PRP to facilitate the establishment of programs using limited resources. Recommendations for staffing and other resources required for a PRP are presented in the first section. Exercise training is a focus of the section on program delivery as this is the component of rehabilitation that has the strongest level of evidence for benefit. Program considerations for patients with respiratory conditions other than COPD are described. Different approaches for delivering the education component of a PRP are outlined and recommendations are made regarding topics for group and individual sessions. The problems commonly encountered in pulmonary rehabilitation, together with recommendations to avoid these problems and strategies to assist in their resolution, are discussed. The review concludes with recommendations for evaluating a PRP.