Six-minute walk test protocol variations in low-resource settings - A scoping review

Features of Heart Failure with Preserved Ejection Fraction in Patients with Chronic Obstructive Pulmonary Disease and Systemic Sclerosis-Associated Interstitial Lung Diseases

Background/Objectives: This study aims to investigate the potential etiopathogenesis of HFpEF development and identify possible different phenotypes of HFpEF in patients with chronic obstructive pulmonary disease (COPD) and systemic sclerosis-associated interstitial lung diseases (SS-ILDs). It could help clinicians improve early HFpEF personalized detection and management. Methods: This study included 150 patients with chronic lung diseases (CLDs), such as COPD and SS-ILD, who were outside of exacerbation, had no history of chronic heart failure (CHF), and had a left ventricular ejection fraction (LV EF) of ≥50%. The functional status of the lungs, heart, endothelial dysfunction, and acid-base balance was assessed. The results obtained were compared in groups of patients with CLD depending on the presence or absence of HF with preserved ejection fraction (HFpEF). The diagnosis of HFpEF was established based on the HFA-PEFF Score classification. Nonparametric statistical methods were used. Results: In patients with CLD, indicators such as age, longitudinal size of the right atrium, mid-regional pro-atrial natriuretic peptide (MR-proANP), and highly sensitive cardiac troponin T (hsTnT) were higher than in the group of patients without HFpEF. In patients with COPD and HFpEF, statistically significant changes were found in the volume of the left atrium. In patients with SS-ILD and HFpEF, statistically significant differenceswere found in SBP before and after the 6 min walk test (6MWT), the Borg scale before 6MWT, MR-proANP, and the longitudinal dimension of the right atrium. Conclusions: The results of our study allow us to identify two different mechanisms of HFpEF development: In patients with COPD, the predominant factor in the development of HFpEF was hypoxia, while in patients with SS-ILD, myocardial dysfunction with remodeling developed against the background of secondary pulmonary hypertension, highlighting the importance of phenotype-specific evaluation. These findings suggest potential approaches for personalized risk stratification and the development of targeted management strategies for patients with HFpEF.

Quality of life in scleroderma-related interstitial lung disease and its association with respiratory clinical parameters

Objectives

Interstitial lung disease in systemic sclerosis has a significant impact in the quality of life. This prospective study was designed to determine the correlation between quality of life in systemic sclerosis-interstitial lung disease patients using patient-reported outcome measures and the lung function test parameters, with assessment done at baseline and 1 year.

Methods

In total, 63 consecutive systemic sclerosis-interstitial lung disease patients underwent lung function test, 6-minute walk distance, and quality of life-validated questionnaires (King's Brief Interstitial Lung Disease and Functional Assessment of Chronic Illness Therapy dyspnea). King's Brief Interstitial Lung Disease covers three components, namely chest, breathlessness, and psychological symptoms. The Functional Assessment of Chronic Illness Therapy dyspnea score has Part I (breathlessness symptoms) and Part II (physical limitation due to breathlessness). All assessments except for 6-minute walk distance were done both at baseline and at 12 months.

Results

Both forced vital capacity predicted percentage at baseline and 12 months had significant negative correlation with the Functional Assessment of Chronic Illness Therapy dyspnea score Part I (p values: 0.038 and <0.001, respectively). Both forced vital capacity and diffuse capacity for carbon monoxide predicted percentage at 12 months were also negatively correlated with Functional Assessment of Chronic Illness Therapy dyspnea score Part II (p values: 0.001 and 0.010, respectively). There was no significant correlation between King's Brief Interstitial Lung Disease score and the lung function parameters, at both baseline and at 1-year interval. Positive significant correlation was observed between forced vital capacity predicted percentage at baseline and 6-minute walk distance (p = 0.001).

Conclusion

Systemic sclerosis-interstitial lung disease affects quality of life, which is best assessed using the Functional Assessment of Chronic Illness Therapy dyspnea score as it correlates significantly with the lung function test parameters.

Cut-off values of one-minute sit-to-stand test for determining physical performance in mild-post-COVID-19 individuals

Background

This study aims to establish cutoff values for the one-minute sit-to-stand test (1STST) to predict physical performance in mild-post- coronavirus disease 2019 (COVID-19) individuals and to compare the 1STST with the 6-minute walk test (6MWT) in assessing hemodynamic response and to explore the correlation between 1STST, 6MWT, and muscle strength, including leg and respiratory muscle strength.

Methods

A cross-sectional study of 93 participants with mild post-COVID-19 symptoms was conducted. Sociodemographic and anthropometric data were collected, and pulmonary function, as well as respiratory and quadriceps muscle strength, were evaluated. Functional capacity was assessed using the 6MWT and 1STST. Additionally, hemodynamic responses, fatigue, and dyspnea were measured before and after each test.

Results

The cutoff for the 1STST in mild post-COVID-19 individuals was ≥29 repetitions, with an AUC of 0.84, sensitivity of 80.52%, and specificity of 75.00%. The 1STST resulted in higher heart rate, systolic blood pressure, and dyspnea compared to the 6MWT, and showed a significant moderate correlation with the 6MWT (r = 0.532, p < 0.0001) and weak correlations with leg strength and respiratory muscle strength.

Conclusion

A cutoff of less than 29 repetitions on the 1STST indicates functional impairment in mild post-COVID-19 cases, as it induces greater physiological stress than the 6MWT and correlates with muscle strength, making it crucial for rehabilitation assessment.

Prediction of Back Disability Using Clinical, Functional, and Biomechanical Variables in Adults with Chronic Nonspecific Low Back Pain

Background: Researchers are focusing on understanding the etiology and predisposing factors of chronic nonspecific low back pain (CNSLBP), a costly prevalent and disabling disorder. Related clinical, functional, and biomechanical variables are often studied, but in isolation. We aimed to identify key factors for managing CNSLBP by examining the relationship between back disability and related clinical, functional, and biomechanical variables and developed prediction models to estimate disability using various variables. Methods: We performed a cross-sectional correlational study on 100 recruited patients with CNSLBP. Clinical variables of pain intensity (visual analog score), back extensor endurance (Sorenson test), functional variables of the back performance scale, 6 min walk test, and the biomechanical variable C7-S1 sagittal vertical axis were analyzed to predict disability (Oswestry disability index). Results: All variables independently, as well as in multi-correlation, were significantly correlated to disability (p < 0.05). The bivariate regression models were significant between back disability and pain intensity (Y = 11.24 + 2.189x), Sorensen results (Y = 105.48 - 0.911x), the back performance scale (Y = 6.65 + 2.486x), 6 min walk test (Y = 49.20 - 0.060x), and sagittal vertical axis (Y = 0.72 + 4.23x). The multi-regression model showed significant contributions from pain (p = 0.001) and Sorensen results (p = 0.028) in predicting back disability, whereas no significant effect was found for other variables. Conclusions: A multidisciplinary approach is essential not only for the management of but also for the assessment of chronic nonspecific low back pain, including its clinical, functional, and biomechanical characteristics. However, special emphasis should be placed on clinical characteristics, including the intensity of pain and back extensor endurance.

"Otherwise … he will be a beggar": a focus group study to understand the Perspectives of physiotherapists about measuring rehabilitation outcomes and impact in low-resource and conflict-affected settings

PURPOSE

Rehabilitation outcomes are important for patients, professionals and policy makers. Most outcome measures (OMs) were developed for "Western" contexts and may be inadequate for low-resource and conflict settings, where the ability to demonstrate impact would be critical to strengthening the sector. This study aims to understand perspectives of physiotherapists from challenging environments regarding current practices, value, barriers, and facilitators of measuring rehabilitation outcomes.

MATERIALS & METHODS

Focus group discussions were held in English with 35 physiotherapists from 18 countries. Audio recordings were transcribed verbatim, anonymised, and analysed using reflexive thematic analysis.

RESULTS

Four themes emerged illustrating the levels at which outcomes and measures were discussed: User (patients, families), provider (physiotherapists, rehabilitation workers), application (OMs), and structure (management, health system). Participants discussed diversity in current practices and patient populations, utility of OMs and a neglected rehabilitation sector lacking investment. Barriers to progressing outcome measurement included lacking patient health literacy, rehabilitation provider training, valid OMs, and leadership. Participants suggested improved patient involvement, routine outcome measurement by using, developing, or adapting simple, context- and stakeholder-relevant OMs, and support from management.

CONCLUSIONS

These insights illustrate the need of and provide robust recommendations for context-adapted development of rehabilitation outcome measurement in various challenging contexts.

Accuracy of the 6-Minute Walk Test for Assessing Functional Capacity in Patients With Heart Failure With Preserved Ejection Fraction and Other Chronic Cardiac Pathologies: Results of the ExIC-FEp Trial and a Meta-Analysis

BACKGROUND

Heart diseases, particularly heart failure, significantly impact patient quality of life and mortality rates. Functional capacity assessment is vital for predicting prognosis and risk in these patients. While the cardiopulmonary exercise test is considered the gold standard, the 6-minute walk test has emerged as a more accessible alternative. However, the screening accuracy and optimal cut-off points of the 6-minute walk test for detecting severely reduced functional capacity in cardiac pathologies, including heart failure with preserved ejection fraction, are unclear. The study aimed to analyse the diagnostic accuracy of the 6-minute walk test for detecting reduced functional capacity, defined as VO2max < 14 ml/kg/min, compared with the cardiopulmonary exercise test in participants with heart failure with preserved ejection fraction using data from the "Ejercicio en Insuficiencia Cardiaca con Fracción de Eyección Preservada" (ExIC-FEp) trial; and to compare these results with previous studies investigating the screening accuracy for assessing functional capacity of the 6-minute walk test in participants with other chronic cardiac pathologies through a meta-analysis.

RESULTS

The ExIC-FEp trial involved 22 participants with heart failure with preserved ejection fraction, who were not treated with beta-blockers, using the cardiopulmonary exercise test, specifically VO2max, as the reference test. The 6-minute walk test had a sensitivity of 70%, a specificity of 80%, and an area under the curve of 76% in the ExIC-FEp trial. Five studies were included in the meta-analysis showing a sensitivity of 79%, a specificity of 78%, and an area under the curve of 85%.

CONCLUSION

In conclusion, the 6-minute walk test holds promise as a screening tool for assessing functional capacity in heart failure with preserved ejection fraction and chronic heart diseases, with a VO2max < 14 ml/kg/min as a reference point. It demonstrates moderate to good screening accuracy. However, the screening accuracy and optimal cut-off points of the 6-minute walk test for detecting severely reduced functional capacity, regardless of aetiology, are unclear.

TRIAL REGISTRATION

NCT05726474. Registered 16 February 2023, https://clinicaltrials.gov/study/NCT05726474 .

Configuration variability of the six-minute walk test among licensed physical therapists working with neurologic conditions: a pilot survey

BACKGROUND

The six-minute walk test (6MWT) is considered reliable and valid for assessing walking capacity in people with neurologic conditions. However, the consistency in the test length and configuration used is unclear.

PURPOSE

To determine how the 6MWT was configured by licensed physical therapists working with patients with neurologic conditions in clinical practice, identify their knowledge of the American Thoracic Society (ATS) and Academy of Neurologic Physical Therapy (ANPT) guidelines for the 6MWT and assess relationships between therapist demographic characteristics and knowledge of the 6MWT guidelines.

METHODS

One hundred forty-six therapists completed a survey related to the configuration they used for the 6MWT.

RESULTS

Configuration of the 6MWT varied widely. Space limitation was the most frequently selected reason for reported configurations. Over half had available the standardized 100-feet straight walkway but fewer than one-third used this configuration of the ATS guidelines. Fewer than half knew of the ATS guidelines and nearly three-fourths knew of the ANPT guidelines. American Physical Therapy Association membership and having a higher percentage of neurologic patients were associated with knowledge of both guidelines.

CONCLUSION

The 6MWT must be completed within the constraints of the working environment, and this requirement is clinically relevant when comparing patient results to normative values and measurements across clinics. Our results suggest a need for updated norms that are more congruent with space constraints in current practice settings.

Determinants and reference values of the 6-min walk distance in the general population-results of the population-based STAAB cohort study

AIMS

The 6-min walk test is an inexpensive, safe, and easy tool to assess functional capacity in patients with cardiopulmonary diseases including heart failure (HF). There is a lack of reference values, which are a prerequisite for the interpretation of test results in patients. Furthermore, determinants independent of the respective disease need to be considered when interpreting the 6-min walk distance (6MWD).

METHODS

The prospective Characteristics and Course of Heart Failure Stages A-B and Determinants of Progression (STAAB) cohort study investigates a representative sample of residents of the City of Würzburg, Germany, aged 30 to 79 years, without a history of HF. Participants underwent detailed clinical and echocardiographic phenotyping as well as a standardized assessment of the 6MWD using a 15-m hallway.

RESULTS

In a sample of 2762 participants (51% women, mean age 58 ± 11 years), we identified age and height, but not sex, as determinants of the 6MWD. While a worse metabolic profile showed a negative association with the 6MWD, a better systolic and diastolic function showed a positive association with 6MWD. From a subgroup of 681 individuals without any cardiovascular risk factors (60% women, mean age 52 ± 10 years), we computed age- and height-specific reference percentiles.

CONCLUSION

In a representative sample of the general population free from HF, we identified determinants of the 6MWD implying objective physical fitness associated with metabolic health as well as with cardiac structure and function. Furthermore, we derived reference percentiles applicable when using a 15-m hallway.

Reference values for six-minute walk distance and six-minute walk work in Caucasian adults

RATIONALE

The six-minute walk test (6MWT) is a practical and simple field-based test to assess physical capacity. Several reference equations for six-minute walking distance (6MWD, m) exist, but have a number of limitations that decrease their clinical utility. In addition, no reference equations exist for the 6MWT-derived outcome six-minute walk work (6MWORK, kg.m).

OBJECTIVES

To establish new reference equations for 6MWD and 6MWORK on a 20 m course using data from the population-based Canadian Cohort Obstructive Lung Disease study.

METHODS AND MEASUREMENTS

A total of 335 participants without obstructive or restrictive pulmonary function, with normal self-reported health status, normal exercise capacity, and <30 pack years cigarette smoking history were selected to create a representative sample of Canadian adults aged ≥40 years. All participants performed two 6MWTs. Reference equations were derived using multiple regression analyses.

MAIN RESULTS

On average, 6MWD and 6MWORK were 541±98 m and 41.3 ± 11.2 kg.m, respectively. All outcomes were significantly greater in males than females. Sex-specific reference equations were derived from the results of 6MWD and 6MWORK with an explained variance of 24 to 35%.

CONCLUSIONS

This study established reference equations for 6MWD and 6MWORK on a 20 m course in Caucasian males and females aged ≥40 years with normal pulmonary function, self-reported health status and exercise capacity. These newly derived reference equations add value to the assessment of functional capacity in clinical practice.

The minimal clinically important difference in the treadmill six-minute walk test in active women with breast cancer during and after oncological treatments

PURPOSE

To examine the minimal clinically important difference (MCID) in the treadmill 6-minute walk test (6MWT) in women with breast cancer.

MATERIALS AND METHODS

A secondary analysis of cross-sectional data from 112 women who were undergoing chemotherapy or had undergone anticancer treatment was conducted. Participants completed the 6MWT on a treadmill and the European Organization for Research and Treatment of Cancer Questionnaire (EORTC-QLQ-C30) twice, eight weeks apart. Change in the physical function domain of the EORTC-QLQ-C30 was used to classify the "positive change" subgroup (≥5 points difference) and the "unchanged" subgroup (<5 points difference). This was combined with the distance difference from the 6MWTs, determining the MCID as the cut-off from the area under the receiver operating characteristic (AUROC) curve (anchor-based determination). The MCID was also determined from (1) the effect size and (2) the difference in standard error (SEM) of the results of the first and second 6MWT (distribution-based determination).

RESULTS

The MCIDs in the during-chemotherapy group was 66.5 and 41.5 m and those in the after-treatment group to be 41.4 and 40.5 m (SEM and effect size based respectively).

CONCLUSIONS

The MCID in the treadmill 6MWT distance could be used to interpret changes in the physical health status of women with breast cancer.IMPLICATIONS FOR REHABILITATIONThe MCID for the 6MWT on treadmill in active women with breast cancer is of approximately 54 m during chemotherapy, and 41.6 m after treatment.The MCID on treadmill 6MWT distance could be used to interpret a decline in the physical health status of women with breast cancer.The 6MWT on treadmill could be an easy, feasible, performed under controlled conditions, alternative to the 6MWT to obtain valuable information in this population.

Reference values and equations for the 6-minute walk distance of Nigerian children aged 6-11 years: A cross-sectional study

BACKGROUND

The 6-minute walk test (6MWT), a simple, reliable, and valid test that uses the distance walked in 6 minute walk distance (6MWD) to quantify functional capacity, is widely used in the management of chronic disorders. However, the absence of reference standards from sub-Saharan African, including Nigerian, school-aged children limits its utility in this age group.

OBJECTIVES

To develop normative values and equations for the 6MWD of school-aged Nigerian children.

METHODS

In a cross-sectional study, healthy children aged 6-11 years in Lagos, Nigeria, completed the 6MWT on 20-m-long straight outdoor courses in their schools. The primary outcome was the 6MWD in meters while potential predictors included demographic (age, sex), anthropometric (height, weight, chest circumference, leg length) and physiologic variables (pre-walk, immediate post-walk, and fifth min-post-walk heart rate [HR], oxygen saturation [SpO₂ ], systolic blood pressure [SBP], diastolic blood pressure [DBP], and rating of perceived exertion [RPE]; and the difference between pre-walk and post-walk HR [∆HR], SpO₂ [∆SpO₂ ], SBP [∆SBP], DBP [∆DBP], and RPE [∆RPE]).

RESULTS

Overall, 627 pupils (52.1% girls) walked 504.6 ± 66.6 m (95% CI: 499.4, 509.8; range: 326.6-673.0 m); 16 m longer in boys (p = 0.002). A stepwise linear regression model yielded: 6MWD (m) = 347.9 + 14(Age_years ) + 1.6 (∆HR_beats/min ) + 17.6(Sex_{male=1, female=0} ) + 1.2(∆SBP_mmHg ); R²  = 0.25. Previously published reference equations mostly over-estimated Nigerian children's 6MWD.

CONCLUSION

These reference standards add to the global normative data on pediatric 6MWT and may be useful for the functional evaluation of Nigerian school-aged children with chronic childhood disorders.

A modified six-minute walk test (6MWT) for low-resource settings-a cross-sectional study

BACKGROUND

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.

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.