Measurement properties of step tests for exercise capacity in COPD: A systematic review

Procedures and measurement properties of the 6-min step test: A systematic review with clinical recommendations

OBJECTIVE

To provide information regarding the procedures, safety, tolerability, and measurement properties of the 6-min step test.

DATA SOURCES

MEDLINE, EMBASE, CINAHL, and SPORTDiscus (from inception until January 2024).

REVIEW METHODS

Studies that examined adults with acute or chronic diseases, and outcomes related to procedures, safety, tolerability, or measurement properties of the 6-min step test were included. Outcome data were summarized and combined in meta-analyses. The quality of included studies was assessed by the Consensus-based Standards for the selection of health Measurement Instruments checklist, and the quality of evidence was determined according to the Grading of Recommendations Assessment, Development, and Evaluation system.

RESULTS

Fourteen studies, involving 847 participants, were included. All studies performed the 6-min step test in 6 min; however, some studies varied the step height and the use of upper limb support. The test appears to be safe and well tolerated by individuals. Moderate- to high-quality evidence demonstrated appropriate results for test-retest reliability (4 studies; Intraclass correlation coefficient 0.96; 95% CI 0.91-0.98; n = 125), criterion validity (4 studies; r = 0.53; 95% CI 0.30-0.71; n = 307), and construct validity (4 studies; r = 0.63; 95% CI 0.52-0.73; n = 233).

CONCLUSION

This review provides recommendations for applying the 6-min step test in clinical and research settings. No adverse events were reported, and the test appears to be well tolerated. Adequate results were found for test-retest reliability, criterion validity, and construct validity.

REVIEW REGISTRATION

PROSPERO (CRD42022347744).

Normative values and prediction equations for the modified incremental step test in healthy adults aged 18-83 years

OBJECTIVE

To establish normative values and reference equations for predicting the number of steps and oxygen consumption (VO2) from the modified incremental step test (MIST) in healthy adults aged 18-83 years.

DESIGN

Prospective observational study.

PARTICIPANTS

One hundred and ninety-four healthy adults aged 18-83 years with normal spirometry.

SETTINGS

Exercise physiology laboratory of a university.

METHODS

Participants underwent two MISTs (30 minutes apart). The MIST was performed on a 20-cm-high step using an externally paced rhythm imposed by audible signals, starting with 10 steps per minute and with constant increments of 1 step every 30 seconds.

MAIN OUTCOMES

Number of steps and VO2 obtained from MIST.

RESULTS

Normative values were provided for males and females for each age group. The following equations were determined: number of steps = 675.113 + (66.165*sex, 0 female and 1 male) - (5.353*age) - (6.593*body mass index) (R² =0.44, P < 0.001); VO2 = 0.106 + (0.216*sex, 0 female and 1 male) - (0.008*age [years]) + (0.021*weight [kilograms]) + (0.001*number of steps) (R² =0.80, P < 0.001).

CONCLUSION

Normative values and prediction equations are proposed for the number of steps and VO2 which can be used to interpret performance on the MIST in individuals with different health conditions. These equations now need validation in other samples.

Measurement properties of the incremental step test for people with chronic obstructive pulmonary disease: a cross-sectional study

OBJECTIVES

The new incremental step test (IST) is a field test that was developed for people with chronic obstructive pulmonary disease (COPD), based on the characteristics of the incremental shuttle walk test (ISWT); however, its measurement properties still need to be determined. We aimed, first, to assess the construct validity (through the comparison with the ISWT), within-day reliability and measurement error of the IST in people with COPD; and, second, to identify whether the participants have a learning effect in the IST.

DESIGN

Cross-sectional study, conducted according to COnsensus-based Standards for the selection of health status Measurement INstruments guidelines.

SETTING

A family health unit in Portugal, April 2022 to June 2023.

PARTICIPANTS AND ANALYSIS

63 participants (67.5±10.5 years) attended two sessions to perform two IST and two ISWT, separately. Spearman's correlations were used to compare the best performances between the IST and the ISWT. Intraclass correlation coefficient (ICC2,1) was used for reliability, and the SE of measurement (SEM), minimal detectable change at 95% CI (MDC95) and Bland and Altman 95% limits of agreement (LoA) were used for measurement error. The learning effect was explored with the Wilcoxon signed-rank test.

RESULTS

The IST was significant and strongly correlated with the ISWT (0.72<ρ<0.74, p<0.001), presented an ICC2,1 of 0.95 (95% CI 0.92 to 0.97), SEM=11.7 (18.9%), MDC95=32.4 (52.2%) and the LoA were -33.61 to 31.48 for the number of steps. No difference was observed between the number of steps of the two attempts of the IST (p>0.05).

CONCLUSIONS

The IST can be suggested as a valid and reliable test to assess exercise capacity in people with COPD, with no learning effect when two IST are performed on the same day. The measurement error of the IST is considered indeterminate.

TRIAL REGISTRATION NUMBER

NCT04715659.

The phase angle cut-off point capable of discriminating hemodialysis patients with reduced exercise tolerance: a cross-sectional study

BACKGROUND

Phase angle (PhA) is a prognostic marker of all-cause mortality in chronic kidney disease. However, no study has investigated this marker as a predictor of exercise intolerance in hemodialysis (HD) patients. The aim of this study was to determine a cut-off point for the PhA capable of discriminating HD patients with reduced exercise tolerance.

METHODS

Thirty-one patients (80.6% men, median age 69 years) were included. The evaluations were performed on three different days, before the HD session. The outcomes evaluated were: biochemical markers, inflammatory and nutritional status, body composition, peripheral muscle strength and exercise tolerance. Performance ≤50% of the predicted value in the six-minute step test (6MST) was defined as reduced exercise tolerance.

RESULTS

Patients presented an average of 67.6 steps (50.5% of predicted) in the 6MST. Fifteen patients (48.4%) were classified with reduced exercise tolerance. The receiver operating characteristic curve indicated a cut-off point of 3.73° for the PhA (sensitivity = 87%, specificity = 81%, and area under the curve = 0.88 [95% CI: 0.76-1.00]; p < 0.001). Patients with reduced exercise tolerance had worse inflammatory and nutritional status, lower PhA and greater impairment of peripheral muscle strength.

CONCLUSION

The cut-off point of 3.73° for the PhA is sensitive and specific to discriminate HD patients with reduced exercise tolerance.

TRIAL REGISTRATION

This study was registered in the Clinical Trials database (no. NCT03779126, date of first registration 19/12/2018).

Comparison of different field tests to assess the physical capacity of post-COVID-19 patients

BACKGROUND

In coronavirus disease (COVID-19), physical capacity is one of the most impaired sequelae. Due to their simplicity and low cost, field tests such as the six-minute walk test (6MWT) are widely used However, in many places it is difficult to perform them and alternatives can be used such as the 1 min sit-to-stand test (1min-STST) or the Chester step test (CST). Therefore, our objective was to compare the 6MWT, 1min-STST and the CST in post-COVID-19 patients.

METHODS

We conducted a cross-sectional analysis in post-COVID-19 patients, compared with matched controls (CG). Demographic characteristics and comorbidities were collected. We analysed oxygen saturation (SpO2), heart rate (HR), and the modified Borg scale in the 6MWT, 1min-STST, and CST. Additionally, the correlations between tests were analysed.

RESULTS

We recruited 27 post-COVID-19 patients and 27 matched controls. The median age was 48 (IQR 43-59) years old (44% female). The median distance walked in 6MWT was 461 (IQR 415-506) m in post-COVID-patients and 517 (IQR 461-560) m in CG (p = 0.001). In 1min-STST, the repetitions were 21.9 ± 6.7 and 28.3 ± 7.1 in the post-COVID-19 group and CG, respectively (p = 0.001). In the CST, the post-COVID-19 group performed 150 (86-204) steps vs the CG with 250 (250-250) steps (p < 0.001). We found correlations between the 6MWT with the 1min-STST in COVID-19 patients (r = 0.681, p < 0.001) and CG (r = 0.668, p < 0.001), and between the 6MWT and the CST in COVID-19 patients (r = 0.692, p < 0.001).

CONCLUSION

The 1min-STST and the CST correlated significantly with the 6MWT in patients post-COVID-19 being alternatives if the 6MWT cannot be performed.

Six-minute stepper test for evaluating functional exercise capacity in patients with sarcoidosis

BACKGROUND

Researchers and clinicians may benefit from alternative tests that do not require large physical spaces or corridors for simply evaluating functional exercise capacity in the clinical practice.

OBJECTIVE

Aim of this study was to investigate whether six-minute stepper test (6MST) is a valid tool for measuring functional exercise capacity in patients with sarcoidosis.

METHODS

Thirty-six patients with sarcoidosis and 18 healthy controls were evaluated with 6MST and six-minute walk test (6MWT). Patients performed 6MST twice. Cardiovascular and symptom responses to tests including heart rate, blood pressure, SpO₂, levels of dyspnea and fatigue were recorded.

RESULTS

Receiver operating characteristic (ROC) curve analysis revealed an area under the ROC curve of 0.74 for 6MST in identifying the patients and controls, indicating acceptable discriminative ability. Patients performed significantly worse in 6MST compared to controls (277±54 vs 349±87 steps; p<0.001). 6MST was able to explain 66% of variance in 6MWT (p<0.001), and there was a strong relationship between 6MWT and 6MST (r = 0.812). SpO₂ responses to tests were similar, however, 6MST generated more severe heart rate, dyspnea and fatigue responses. Intraclass correlation coefficient calculated for initial and retest scores of 6MST was 0.990, indicating excellent test-retest reliability. However, there was a systematical improvement (∼4%) in retest 6MST scores.

CONCLUSIONS

6MST is a valid and reliable alternative test for measuring functional exercise capacity in sarcoidosis. 6MST may also help better testing the upper limits of cardiac system and physical endurance as it is more physically demanding than 6MWT.

Assessment of Exercise Capacity in Post-COVID-19 Patients: How Is the Appropriate Test Chosen?

There is a wide range of sequelae affecting COVID-19 survivors, including impaired physical capacity. These sequelae can affect the quality of life and return to work of the active population. Therefore, one of the pillars of following-up is the evaluation of physical capacity, which can be assessed with field tests (such as the six-minute walk test, the one-minute standing test, the Chester step test, and the shuttle walking test) or laboratory tests (such as the cardiopulmonary exercise test). These tests can be performed in different contexts and have amply demonstrated their usefulness in the assessment of physical capacity both in post-COVID-19 patients and in other chronic respiratory, metabolic, cardiologic, or neurologic diseases. However, when traditional tests cannot be performed, physical function can be a good substitute, especially for assessing the effects of an intervention. For example, the Short Physical Performance Battery assessment and the Timed Up and Go assessment are widely accepted in older adults. Thus, the test should be chosen according to the characteristics of each subject.

A systematic review of exercise studies for individuals hospitalized with an acute exacerbation of chronic obstructive pulmonary disease: Focus on the principles of exercise training

BACKGROUND

For exercise interventions to be effectively reproduced or applied in a "real world" clinical setting, clinical trials must thoroughly document all components of the exercise prescription and ensure that participants adhere to each component. However, previous reviews have not critically examined the quality of exercise prescription of inpatient Pulmonary Rehabilitation (PR) programs.

OBJECTIVE

The objectives of this review were to evaluate the (a) application of the principles of exercise training, (b) reporting of the frequency, intensity, time and type (FITT) components of exercise prescription, and (c) reporting of patient's adherence to the FITT components in intervention studies for patients admitted to hospital for an acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

METHODS

Relevant scientific databases were searched for randomized controlled trials (RCTs) that compared in-hospital PR with usual care for people hospitalized with AECOPD. Title and abstract followed by full-text screening were conducted independently by two reviewers. Data were extracted and synthesized to evaluate the application of the principles of exercise training and the reporting/adherence of the FITT components.

RESULTS

Twenty-seven RCTs were included. Only two applied all principles of exercise training. Specificity was applied by 70%, progression by 48%, overload by 37%, initial values by 89% and diminishing returns and reversibility by 37% of trials. Ten trials adequately reported all FITT components. Frequency and type were the components most reported (85% and 81%, respectively), while intensity was less frequently reported (52%). Only three trials reported on the patient's adherence to all four components.

CONCLUSIONS

Studies have not adequately reported the exercise prescription in accordance with the principles of exercise training nor reported all the FITT components of the exercise prescription and patient's adherence to them. Therefore, interpretation of the current literature is limited and information for developing exercise prescriptions to individuals hospitalized with an AECOPD is lacking.

The Chester Step Test Is a Reproducible Tool to Assess Exercise Capacity and Exertional Desaturation in Post-COVID-19 Patients

Many people recovering from an acute episode of coronavirus disease (COVID-19) experience prolonged symptoms. Exercise testing is a feasible and cost-effective option for assessing exercise tolerance, fatigue, and dyspnea related to effort. Being that the Chester step test (CST) is a progressive, submaximal test for predicting aerobic capacity, it could be a good option to explore. This study aimed to determine the reproducibility of CST for assessing exertional desaturation and exercise capacity in patients post-COVID-19 disease. A cross-sectional study was conducted on post-COVID-19 patients. Two attempts of the CST were performed. The intraclass correlation coefficient (ICC) was used to assess agreement between the two tests. Forty-two symptomatic post-COVID-19 patients were included, the mean age was 53.8 ± 10.3 years, and 52% were female. There was no significant difference between both tests (p = 0.896). Twenty-four percent of participants (10 cases) had a clinically significant decrease in SpO₂ at the first assessment, compared to 30.1% (13 cases) at the second, with no significant difference. An ICC of 0.993 (95% CI: 0.987 to 0.996) was obtained for the total number of steps in the CST.

Community-Based Pulmonary Rehabilitation Programs in Individuals With COPD

BACKGROUND

Community-based pulmonary rehabilitation (PR) programs can be offered to patients with COPD, but the literature on its effects is still not well summarized. Our purpose was to investigate the health-, physical-, and respiratory-related effects of community-based PR in individuals with COPD as compared to control groups.

METHODS

The PubMed and Embase databases were searched up to May 17, 2021. We included randomized control trials that compared the effects of community-based PR as compared to control groups in individuals with COPD. The risk of bias was judged using the Cochrane Risk of Bias 2 (RoB2). Meta-analysis was performed using a random-effects model to estimate the standardized mean difference (SMD) with 95% CI of the mean changes from baseline between groups. The Grading of Recommendations Assessment, Development, and Evaluation was used to interpret certainty of results.

RESULTS

We included 10 randomized control studies comprising a total of 9,350 participants with weighted mean age of 62.3 ± 2.38 y. The community-based interventions were based on exercise programs (resistance and/or endurance). All studies were judged as high risk and/or some concerns in one or more domains the risk of bias. All meta-analyses displayed very low certainty of evidence. The community-based PR interventions were significantly superior to control interventions in improving the St. George Respiratory Questionnaire Activity subscore (-0.40 [95% CI -0.72 to -0.08]; k = 5, n = 382) and total score (-0.73 [95% CI -1.29 to -0.18]; k = 4, n = 268) and the Chronic Respiratory Disease Questionnaire dyspnea subscore (0.36 [95% CI 0.03-0.69]; k = 6, n = 550). The mean changes from baseline were not different between the groups for all other outcomes.

CONCLUSIONS

Community-based PR tended to result in superior health-related quality of life and symptoms than control interventions, but the findings were inconsistent across outcomes and with very low certainty of evidence. Further studies are warranted for stronger conclusions.

Validity and reliability of a new incremental step test for people with chronic obstructive pulmonary disease

BACKGROUND

Incremental step tests (IST) can be used to assess exercise capacity in people with chronic obstructive pulmonary disease (COPD). The development of a new step test based on the characteristics of the incremental shuttle walk test (ISWT) is an important study to explore. We aimed to develop a new IST based on the ISWT in people with COPD, and assess its validity (construct validity) and reliability, according to Consensus-based Standards for the selection of health status Measurement Instruments (COSMIN) recommendations.

METHODS

A cross-sectional study was conducted in participants recruited from hospitals/clinics. During the recruitment, the participants who presented a 6-minute walk test (6MWT) report in the previous month were also identified and the respective data was collected. Subsequently, participants attended two sessions at their homes. IST was conducted on the first visit, along with the 1 min sit-to-stand (1MSTS) test. IST was repeated on a second visit, performed 5-7 days after the first one. Spearman's correlations were used for construct validity, by comparing the IST with the 6MWT and the 1MSTS. Intraclass correlation coefficient (ICC_2,1), SE of measurement (SEM) and minimal detectable change at 95% CI (MDC95) were used for reliability. The learning effect was explored with the Wilcoxon signed-rank test.

RESULTS

50 participants (70.8±7.5 years) were enrolled. IST was significant and moderate correlated with the 6MWT (ρ=0.50, p=0.020), and with the 1MSTS (ρ=0.46, p=0.001). IST presented an ICC_2,1=0.96, SEM=10.1 (16.6%) and MDC95=27.9 (45.8%) for the number of steps. There was a statistically significant difference between the two attempts of the IST (p=0.030).

CONCLUSION

Despite the significant and moderate correlations with the 6MWT and 1MSTS, the inability to full compliance with the COSMIN recommendations does not yet allow the IST to be considered valid in people with COPD. On the other hand, the IST is a reliable test based on its high ICC, but a learning effect and an 'indeterminate' measurement error were shown.

TRIAL REGISTRATION NUMBER

NCT04715659.

Test-Retest Reliability and Validity of the Six Minute Stepper Test to Evaluate Functional Exercise Capacity in Patients with Ankylosing Spondylitis

OBJECTIVES

The 6-minute stepper test (6MST) is a submaximal test that requires little space to assess exercise capacity compared to the 6-minute walk test (6MWT). The study aims to investigate the test-retest reliability and convergent validity of 6MST and to compare physiological responses, dyspnea, fatigue perception with 6MST and 6MWT in patients with ankylosing spondylitis (AS).

METHODS

To test the convergent validity of 6MST, 65 patients performed both 6MWT and 6MST on the first day and correlation between two tests were assessed with Pearson correlation test. In order to investigate the test-retest reliability of the 6MST, thirty-two of the 65 patients performed 6MST one week later and intraclass correlation coefficients (ICC) were calculated. Dyspnea and fatigue perception were analyzed with using Wilcoxon signed-rank test, physiological responses were analyzed using paired sample t-test.

RESULTS

Excellent test-retest reliability was observed for 6MST (ICC: 0.988). There was a significant correlation between 6MST and 6MWT (r: 0.725, p<0.001). Dyspnea and leg fatigue perception were significantly higher in 6MST (p<0.05). Physiological responses and fatigue perception were similar in both 6MST and 6MWT (p>0.05).

CONCLUSION

This study demonstrated that the 6MST is reliable and valid method to evaluate exercise capacity in patients with AS. 6MST can be used to evaluate exercise capacity of patients with AS.

Effects of a Home-Based Pulmonary Rehabilitation Program in Patients with Chronic Obstructive Pulmonary Disease in GOLD B Group: A Pilot Study

Patients with chronic obstructive pulmonary disease (COPD) in the Global Initiative for Chronic Obstructive Lung Disease (GOLD) B group can be included in pulmonary rehabilitation (PR) settings outside the hospitals. This study aimed to explore the feasibility of a home-based pulmonary rehabilitation (HBPR) program and assess its impact on patients with COPD in the GOLD B group. A real-world, pre–post intervention study was conducted with 12 weeks of HBPR (presential home visits and phone calls) using the self-management program Living Well with COPD. The 1-min sit-to-stand test (1MSTS), modified Medical Research Council Questionnaire (mMRC), COPD Assessment Test (CAT), Hospital Anxiety and Depression Scale (HADS), and London Chest Activity of Daily Living (LCADL) were used to assess the impact. Pre–post differences and correlations between changes in outcomes were calculated. In 30 patients (71.6 years, FEV₁ (%) 52.8), significant improvements (p < 0.05) were observed on 1MSTS (Pre 17.2, Post 21.2), mMRC (Pre 2.0, Post 1.0), CAT (Pre 16.3, Post 9.9), HADS (Pre 14.4, Post 9.6), and LCADL (Pre 21.0, Post 15.8), with no adverse events reported. When significant, correlations between changes in outcomes were moderate or strong (0.48 ≤ ρ ≤ 0.66). HBPR can be feasible and safe, and it shows the potential to significantly improve outcomes of patients with COPD in the GOLD B group.

Adapted Chester Step Test Can Have Maximal Response Characteristics for the Assessment of Exercise Capacity in Young Women

Chester step test (CST) estimates the exercise capacity through a submaximal response, which can limit its application in the prescription of exercise. This study aimed to assess whether an adaptation of the CST (with a progressive profile) can have maximal response characteristics in young women and compare it to the incremental shuttle walk test (ISWT). Another aim was to determine its within-day test–retest reliability. A cross-sectional study was conducted with 25 women (20.3 ± 1.5 years) who performed the field tests twice on two different days (48 h apart). The maximal effort attainment was assessed by the heart rate (HR), perception of exertion (Borg scale), and blood lactate concentration. For the performance variables, Pearson’s correlation and intraclass correlation coefficient (ICC_2,1) were used. In the best test, mean values of maximal response were observed in the adapted CST (94.0 ± 6.5% of age-predicted HR_max, 11.3 ± 4.5 mmol/dl of blood lactate, and 18.4 ± 1.5 of Borg rating). The correlations between the adapted CST and the ISWT were weak to moderate (0.38 ≤ r ≤ 0.55; p < 0.05). Fair to good reliability was found for the adapted CST (ICC_2,1 = 0.48–0.61). The adapted CST showed mean values of maximal response, weak to moderate association with the ISWT, and low within-day test–retest reliability in young women.