The Influence of Alternative Instruction on 6-Min Walk Test Distance

doi:10.1378/chest.13-0287

Chest

Volume 144, Issue 6, December 2013, Pages 1900-1905

https://doi.org/10.1378/chest.13-0287 Get rights and content

Background

The goal of the 6-min walk test (6MWT) is to enable patients to walk “as far as possible” as a measure of their functional ability. The impact of the specific walk instructions on patient 6MWT performance is unknown.

Methods

Patients with pulmonary arterial hypertension (PAH), idiopathic pulmonary fibrosis (IPF), and other forms of interstitial lung disease (ILD) were recruited to perform four identical 6MWTs with one differing instructional phrase. The standard instruction to walk “as far as possible” was substituted in random order with “as fast as possible,” “at your normal pace,” or “at a leisurely pace.”

Results

Twenty-four patients (10 with PAH, eight with IPF, six with other ILD) were enrolled and completed all four 6MWTs. Patients attained the greatest distance with the fast instruction, exceeding the standard instruction distance by a mean of 52.7 m (P < .001). The mean difference between the fast and standard walks was 41.5 m in the PAH group, 66.5 m in the IPF group, and 53 m in the other ILD group.

Conclusions

Patients do not walk as far as they are able with the standard American Thoracic Society instruction for 6MWT. Changing the wording from “far” to “fast” may facilitate a better effort and greater distance during the test. It is possible that this modified 6MWT instruction may result in improved accuracy and reproducibility, thereby enhancing its clinical and research trial usefulness.

Trial registry

ClinicalTrials.gov; No.: NCT01789996; URL: www.clinicaltrials.gov

Section snippets

Materials and Methods

Patients were prospectively recruited and enrolled from an Advanced Lung Disease clinic between June 2010 and April 2011. Patients with pulmonary arterial hypertension (PAH), idiopathic pulmonary fibrosis (IPF), and other forms of interstitial lung disease (ILD) were included. Patients with significant musculoskeletal disease, those who used supplemental oxygen at rest, and those who had a history of unstable angina or cardiac arrhythmia were excluded.

After informed consent was obtained, all

Results

Twenty-four patients consented to and completed the study. The mean age of the group was 56 years (range, 32-78 years), and 63% were women. The mean BMI was 29.2 kg/m² (range, 19.8-41.6 kg/m²). The mean FVC % predicted was 74.2 (range, 54-103), and the mean single-breath diffusing capacity of the lung for carbon monoxide % predicted was 49.6 (range, 31-84). Ten patients had PAH, eight patients had IPF, and six patients had another form of ILD. The demographics of the individual patient groups

Discussion

The 6MWT is a practical functional test that is used both clinically and as an end point in clinical trials, especially in the PAH field. The goal of the 6MWT is for patients to walk as far as possible; however, the optimal instruction to enable this has never been tested, nor has the possible range of outcomes been established. In this study, we demonstrated a wide range in distances attained based on differing instructions prior to the test. This underscores the importance of appropriate and

Conclusions

In conclusion, we have demonstrated a broad range of walk distances resulting from alterations in 6MWT instruction. Somewhat paradoxically, it is the “walk as fast as you can” instruction that results in walking the furthest. Our data suggest that consideration be given to changing the standard 6MWT instruction to maximize the distance and thereby possibly reduce the inherent intrapatient variability that undermines the usefulness of this test and its use in a serial fashion. Because of the use

Acknowledgments

Author contributions: Drs Weir and Nathan are the guarantors of the paper and take responsibility for the integrity of the work as a whole, from inception to published article.

Dr Weir: contributed to the inception of the idea, the analysis and interpretation of the data, and the writing of the paper.

Dr Brown: contributed to the inception of the idea, the analysis and interpretation of the data, and the writing of the paper.

Dr Shlobin: contributed to the inception of the idea, the analysis and

References (0)

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A modified six-minute walk test (6MWT) for low-resource settings-a cross-sectional study
2022, Heart and Lung
Citation Excerpt :
In neither of the configurations of our study, including the standard 6MWT, such cardiorespiratory responses were identified. An important factor to consider here may pertain to the understanding of the 6MWT instructions; particularly in settings where literacy and quality education are not a given To illustrate, a study investigating the influence of alternate instructions on 6MWD concluded that when using phrases such as “walk as fast as you can” instead of the standardized “walk as far as you can” results in a larger 6MWD.36 The ability to make an informed “judgment” as to what is required to walk “as far as you can” requires a level of abstract thinking that may be jeopardized, specifically when growing up or living in a low-resource setting.11,27
The 6 min walk test (6MWT) is a validated tool used to assess functional capacity in a variety of patient populations. Space constraints often limit the practicality of the 6MWT according to the standard (2002) American Thoracic Society protocol, and therefore, adaptations to this protocol are common with potential implications for research and clinical practice. Furthermore, such implications for research and clinical practice may be augmented in low-resourced settings.
To determine the agreement between the 6 min walk distance (6MWD) achieved on the standard 30 m (6MWT₃₀), and a straight 10 m (6MWT₁₀), or 10 m figure-of-eight (6MWT_F8) configuration, respectively.
A cross-sectional study was conducted in a socioeconomic challenged community. A heterogeneous sample of adults (n = 27) with non-communicable disease were randomized into performing the 6MWT₁₀ (n = 15) or 6MWT_F8 (n = 12), in addition to the standard 6MWT₃₀. Pairwise comparison and concordance correlation coefficients were used to assess agreement.
The mean (SD) 6MWD₃₀ was 437(42) meters, while the mean 6MWD₁₀ was 371(57). The mean difference (SE; p-value) between the 6MWD₃₀ and 6MWD₁₀ was 67 m (8.6; p .01). The mean 6MWD₃₀ was 424(67) meters, while the mean 6MWD_F8 was 347(58). The mean difference between the 6MWD₃₀ and 6MWD_F8 was 77 m (6.0; p .01). Moderate concordance was found between the 6MWT₃₀ and 6MWT_F8 or 6MWD₁₀, respectively.
The present data suggest that, independent of configuration, using a shorter pathway significantly reduced the 6MWD. Low-resource settings may benefit from contemporary measures of functional capacity more conducive to resource constraints, or standardization of the test when used in such settings.
Standardization of the 6-min walk test in clinical trials of idiopathic pulmonary fibrosis
2021, Contemporary Clinical Trials
Citation Excerpt :
Each site is provided with customized floor markers and a clipboard. Encouragement has been shown to significantly improve performance in the 6MWT, with slight variations in wording affecting the distance walked [24,39]. Of the previous phase 3 IPF trials using the 6MWT, only one (STEP-IPF) was found to detail the encouragement given [8,10–12].
The 6-min walk test (6MWT) is an important measure of functional capacity in idiopathic pulmonary fibrosis (IPF) and has been an endpoint of several IPF clinical trials. However, current guidance for the 6MWT offers insufficient advice on standardization, particularly oxygen supplementation, for clinical trials. Three physicians experienced with the 6MWT and IPF developed a standardized protocol for the 6MWT based on existing clinical guidelines and published literature. The protocol comprises guidance on test conditions, pre-defined parameters to measure at specified timepoints, and step-by-step instructions on conducting the test. The standardized test will be evaluated in the large-scale phase 3 ISABELA trials (NCT03711162; NCT03733444). The test is conducted indoors, using standardized equipment, along a flat, straight, 30-m unobstructed corridor; tests for each individual are performed by the same administrators at the same time of day; warm-up prior to testing is prohibited; supplemental oxygen tanks are permitted and moved by the patient in the same manner for each test; precise wording is used to instruct and encourage patients. Contraindications and stopping criteria are specified. Key assessments include: 6-min walk distance, distance walked at 1 and 3 min, the Borg CR10 scale, heart rate, blood pressure, and oxygen desaturation levels. A standardized 6MWT for IPF will enable more reliable comparisons between clinical trials and limit variability, optimizing use as an endpoint. Application of the standardized 6MWT in the ISABELA program will allow its correlation with other clinically important endpoints and may lead to novel composite endpoints for use in future trials.
Submission category: Study Design, Statistical Design, Study Protocols.
Submission classifications: Clinical study methodology; Clinical trial design; Clinical trials; Pulmonary disease; Pulmonary disease clinical trial; Respiratory medicine.
Circulating NEDD9 is increased in pulmonary arterial hypertension: A multicenter, retrospective analysis
2020, Journal of Heart and Lung Transplantation
Pulmonary arterial hypertension (PAH) is a highly morbid disease characterized by elevated pulmonary vascular resistance (PVR) and pathogenic right ventricular remodeling. Endothelial expression of the prometastatic protein NEDD9 is increased in fibrotic PAH arterioles, and NEDD9 inhibition decreases PVR in experimental PAH. We hypothesized that circulating NEDD9 is increased in PAH and informs the clinical profile of patients.
Clinical data and plasma samples were analyzed retrospectively for 242 patients from 5 referral centers (2010–2017): PAH (n = 139; female 82%, 58 [48–67] years), non-PAH pulmonary hypertension (PH) (n = 54; female 56%, 63.4 ± 12.2 years), and dyspnea non-PH controls (n = 36; female 75%, 54.2 ± 14.0 years).
Compared with controls, NEDD9 was increased in PAH by 1.82-fold (p < 0.0001). Elevated NEDD9 correlated with PVR in idiopathic PAH (ρ = 0.42, p < 0.0001, n = 54), connective tissue disease (CTD)-PAH (ρ = 0.53, p < 0.0001, n = 53), and congenital heart disease–PAH (ρ = 0.68, p < 0.0001, n = 10). In CTD-PAH, NEDD9 correlated with 6-minute walk distance (ρ = −0.35, p = 0.028, n = 39). In contrast to the PAH biomarker N-terminal pro-brain natriuretic peptide (n = 38), NEDD9 correlated inversely with exercise pulmonary artery wedge pressure and more strongly with right ventricular ejection fraction (ρ = −0.41, p = 0.006, n = 45) in a mixed population. The adjusted hazard ratio for lung transplant–free survival was 1.12 (95% confidence interval [CI], 1.02–1.22, p = 0.01) and 1.75 (95% CI, 1.12–2.73, p = 0.01) per 1 ng/ml and 5 ng/ml increase in plasma NEDD9, respectively, by Cox proportional hazard model.
In PAH, plasma NEDD9 is increased and associates with key prognostic variables. Prospective studies that include hard end points are warranted to validate NEDD9 as a novel PAH biomarker.
Six-Minute Walk Test: Clinical Role, Technique, Coding, and Reimbursement
2020, Chest
Citation Excerpt :
The scripted instructions in the guidelines state “the object of this test is to walk as far as possible for 6 minutes.”10 In a study of patients with idiopathic pulmonary fibrosis (IPF), interstitial lung disease, and pulmonary arterial hypertension (PAH), focus on speed by instructing them to “walk as fast as you can” led to a considerable increase in 6MWD.24 Nevertheless, it is recommended against use of this phrase because the initial benefit of increased speed may be offset by fatigue experienced later and may place undue stress on patients with cardiac conditions.11
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.
Learning and Encouragement Effects on Six-Minute Walking Test in Children
2018, Journal of Pediatrics
To evaluate learning and encouragement effects on the 6-minute walk test in children between 6 and 12 years of age.
Two 6-minute walk tests separated by a 10-minute resting period were performed by healthy children between 6 and 12 years of age to evaluate the learning (part 1) and encouragement effects (part 2; randomization with and without encouragement). Distance and cardiorespiratory variables were used as outcomes.
148 children were recruited. The intraclass correlation coefficient estimates were 0.927 (95% CI, 0.893-0.951; part 1) and 0.844 (95% CI, 0.744-0.907; part 2). The test-retest agreement was verified for distance (P = .679) with a bias of 1.1 m (95% CI, −4 to 6), but the increase in distance with encouragement was significantly and clinically relevant (P < .001; +41 m; 95% CI, 33-50).
No training is required for the 6-minute walk test in children, in contrast with adults, but there was an encouragement effect on the walked distance in these children. Guidelines should take these results into account.
ClinicalTrials.gov: NCT03276299.
Preoperative exercise therapy in surgical care: a scoping review
2016, Journal of Clinical Anesthesia
Citation Excerpt :
The 6MWT has largely replaced other exercise testing modalities in the assessment of several diseases including cardiovascular and pulmonary diseases. Advantages are the low cost, simplicity, ease of performance, reproducibility, and ability to perform the test in a clinic with minimal equipment [54,55]. Future research should therefore focus on identifying alternative simple and inexpensive tests that are sensitive in evaluating cardiopulmonary functioning.
Several systematic reviews have focused on the role of preoperative exercise therapy (PET) in various fields of surgical care. Aims of the present scoping review are to summarize research findings and to identify gaps in existing literature.
Two authors independently conducted a comprehensive literature search on systematic reviews regarding PET. The risk of bias was assessed using “the methodology checklist for systematic reviews and meta-analyses of the Scottish Intercollegiate Guidelines Network (SIGN).” Findings of the included systematic reviews were summarized according to type of surgery and type of PET.
Twenty-one reviews on PET with a low risk of bias were included. Seven reviews investigated PET in multiple surgical fields and 14 in just a single surgical field. PET was studied before cardiac surgery (n = 9), orthopedic surgery (n = 8), abdominal surgery (n = 8), thoracic surgery (n = 8), vascular surgery (n = 3), and urologic surgery (n = 1).
Overall, it seems that PET exerts beneficial effects on physical fitness and postoperative outcome measures. Gaps in current literature are the heterogeneity in selected patient populations and outcome measures as well as lack of guidelines on the specific PET regimes. Therefore, there is increasing need for multicenter randomized trials with specifically designed PET programs and a carefully selected patient population to strengthen current evidence.

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Funding/Support: This study was supported by a seed grant of $7,500 from Inova Fairfax Hospital and by the NIH-Inova Advanced Lung Disease Program Fund and the National Heart Lung and Blood Institute Fund.

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Chest

Original ResearchPulmonary PhysiologyThe Influence of Alternative Instruction on 6-Min Walk Test Distance

Background

Methods

Results

Conclusions

Trial registry

Section snippets

Materials and Methods

Results

Discussion

Conclusions

Acknowledgments

Original Research
Pulmonary Physiology
The Influence of Alternative Instruction on 6-Min Walk Test Distance