Effectiveness of smartphone-assisted cardiac rehabilitation: a systematic review and meta-analysis

PURPOSE

To explore the effectiveness of smartphone-assisted home cardiac rehabilitation and whether it can be used as a remote detection method to promote home cardiac rehabilitation.

METHODS

Four databases were searched to collect randomized controlled trials (RCTs) about smartphone-assisted cardiac rehabilitation. The Cochrane risk-of-bias tool was used to assess the methodological quality of the included studies. Two independent investigators performed the literature screening, information extraction, and risk of bias assessment. Any disagreements were resolved by a third investigator. Meta-analysis and systematic review were performed. Sensitivity analysis and subgroup analysis were carried out to explore the sources of heterogeneity.

RESULTS

A total of 14 RCTs involving 1962 patients were included. Meta-analysis showed that compared with conventional cardiac rehabilitation/usual care, smartphone-assisted cardiac rehabilitation significantly improved VO2peak in patients with cardiovascular disease (WMD= 1.32, 95%CI:0.82 to 1.81, p > 0.05) and enhanced their treatment compliance (RR = 1.62, 95%CI:1.21 to 2.17, p > 0.05). There were no significant differences in six-minute walk distance (WMD = 12.88, 95%CI:-0.82 to 26.57, p > 0.05), body mass index (BMI) (WMD=-0.14, 95%CI:-0.34 to 0.06, p > 0.05), life quality, psychological status, and other cardiovascular risks.

CONCLUSION

Smartphone-assisted cardiac rehabilitation showed significant improvement in exercise capacity and treatment compliance in patients with cardiac rehabilitation but did not improve BMI, quality of life, psychological status, or reduce other cardiovascular risks. Smartphone-based cardiac rehabilitation is increasingly used as a remote detection method for cardiac rehabilitation in middle-income countries, which provides new insights into home cardiac rehabilitation.

Association between trunk extensor strength and gait-induced back pain in the elderly with adult spinal deformity: a cross-sectional study

PURPOSE

The purpose of the present study was to investigate the association between quantitatively assessed trunk extensor strength and gait-induced back pain (GIBP) in patients with adult spinal deformity (ASD).

METHODS

Ninety-five patients with ASD aged ≥ 50 years who were admitted to our hospital between April 2018 and March 2023 were included in the study. GIBP was evaluated through a 6-minute walking test (6MWT), with GIBP being defined as the occurrence of back pain during the evaluation and inability to complete the test. The patients were divided into three groups: difficulty completing the 6MWT (Group 1), ability to complete the 6MWT with breaks (Group 2), and ability to complete the 6MWT without taking a break (Group 3). The main independent variable was trunk extensor strength, which was measured using a hand-held dynamometer. Ordered logistic regression analysis was conducted to assess the association between GIBP and trunk extensor strength while adjusting for basic characteristics and radiographic parameters as covariates.

RESULTS

The numbers of patients with ASD included in each group were; 27 in Group 1 (28.4%), 31 in Group 2 (32.6%), and 37 in Group 3 (39.0%). An ordered logistic regression analysis adjusted for basic characteristics and radiographic parameters, trunk extensor strength was significantly associated with GIBP (odds ratios, 1.128; 95% confidence intervals, 1.025-1.242).

CONCLUSIONS

The results of the present study strongly indicate that trunk extensor strength is a valuable factor associated with GIBP in patients with ASD.

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 .

Clinical utility of the Borg dyspnoea score in 6-minute walk tests in interstitial lung disease: A systematic review

BACKGROUND

Exertional dyspnoea, a cardinal symptom in interstitial lung disease (ILD), can be objectively measured during a 6-min walk test (6MWT) using the Borg Dyspnoea Score (BDS). However, the clinical utility of this measurement is unclear. The purpose of this systematic review was to determine the association between 6MWT BDS and prognosis (mortality and lung transplantation), other 6MWT variables and measures of pulmonary function.

METHODS

MEDLINE, EMBASE, Cochrane and SCOPUS databases were used to identify studies reporting an association between post-6MWT BDS and the relevant outcomes in adults with ILD. Language was limited to English. Study quality was assessed using the Quality in Prognosis Study risk of bias tool. A narrative synthesis for each outcome was performed.

RESULTS

Ten full-text studies (n = 518) were included. Four studies had high overall risk of bias. Two studies (n = 127) reported prognosis and both found that higher 6MWT BDS was associated with increased all-cause mortality. However, the certainty of evidence was very low due to study design and likely publication bias. Higher post-6MWT BDS may be associated with shorter, or no effect on 6MWD; and lower pulmonary function. There was insufficient evidence that BDS correlated with 6MWT oxygen saturation.

CONCLUSIONS

Post-6MWT BDS has a potential role as a predictor of all-cause mortality in ILD, 6MWD and lower pulmonary function. Larger studies designed to confirm these relationships and assess the independent association between the 6MWT BDS and clinical outcomes are required.

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.

Digital measurement of mobility in pulmonary arterial hypertension: A structured review of an emerging area

This review examined literature that has examined mobility in pulmonary arterial hypertension (PAH) using digital technology. Specifically, the review focussed on: (a) digital mobility measurement in PAH; (b) commonly reported mobility outcomes in PAH; (c) PAH specific impact on mobility outcomes; and (d) recommendations concerning protocols for mobility measurement in PAH. PubMed, Scopus, and Medline databases were searched. Two independent reviewers screened articles that described objective measurement of mobility in PAH using digital technology. Twenty-one articles were screened, and 16 articles met the inclusion/exclusion criteria and were reviewed. Current methodologies for mobility measurement in PAH with digital technologies are discussed. In brief, the reviewed evidence demonstrated that there is a lack of standardisation across studies for instrumentation, outcomes, and interpretation in PAH. The validity and reliability of digital approaches were insufficiently reported in all studies. Future research is required to standardise digital mobility measurement and characterise mobility impairments in PAH across clinical and real-world settings. The reviewed evidence suggests that digital mobility outcomes may be useful clinical measures and may be impaired in PAH, but further research is required to accurately and robustly establish findings. Recommendations are provided for future studies that encompass comprehensive reporting, validation, and measurement.

Impact of Test Instructions on 6-min Walk Distance in Adults With Chronic Respiratory Disease: A RANDOMIZED CONTROLLED TRIAL

PURPOSE

The 6-min walk test (6MWT) is commonly used to assess functional exercise capacity in people with chronic respiratory disease in both clinical and research settings. However, two tests are required to achieve accurate results, due to a well-documented learning effect for the 6-min walk distance (6MWD). Whether it is possible to reduce or eliminate the learning effect by optimizing 6MWT instructions is not known.

METHODS

People with chronic respiratory disease referred to pulmonary rehabilitation undertook two 6MWT with random allocation to modified instructions ( fast -walk as fast as possible; n = 46) or usual instructions ( far -walk as far as possible; n = 49). The primary outcome was the learning effect, defined as the difference in the 6MWD between test one and test two. Subgroup analyses investigated whether effects varied in those who were naïve to the 6MWT or according to diagnosis (chronic obstructive pulmonary disease, interstitial lung disease, and bronchiectasis).

RESULTS

A learning effect was present in both groups, with a mean improvement in the 6MWD on the second test of 14 m in the fast (modified) group (95% CI, 6-22) and 11 m in the far (usual) group (95% CI, 4-19). There was no statistically or clinically significant difference between groups in the magnitude of the learning effect (between-group difference -3 m, 95% CI, -14 to 8). There was no significant effect of naivety to the 6MWT or diagnosis.

CONCLUSION

The current recommended procedures for the 6MWT, including standardized instructions and performance of two tests on each occasion, should be retained.

Test-retest reliability of the six-minute walking distance measurements using FeetMe insoles by completely unassisted healthy adults in their homes

Wearable technology provides an opportunity for new ways of monitoring patient gait remotely, through at-home self-administered six-minute walk tests (6MWTs). The purpose of this study was to evaluate the test-retest reliability of FeetMe insoles, a wearable gait assessment device, for measuring the six-minute walking distance (6MWD) during tests conducted with a one-week interval by completely unassisted healthy adults in their homes. Participants (n = 21) performed two 6MWTs at home while wearing the FeetMe insoles, and two 6MWTs at hospital while wearing FeetMe insoles and being assessed by a rater. All assessments were performed with a one-week interval between tests, no assistance was provided to the participants at home. The agreement between the 6MWD measurements made at baseline and at Week 1 was good for all test configurations and was highest for the at-home FeetMe measurements, with an intraclass correlation coefficient (ICC) of 0.95, standard error of the measurement (SEM) of 15.02 m and coefficient of variation (CV) of 3.33%, compared to ICCs of 0.79 and 0.78, SEMs of 25.65 and 26.65 and CVs of 6.24% and 6.10% for the rater and FeetMe measurements at hospital, respectively. Our work demonstrates that the FeetMe system could provide a reliable solution allowing individuals to self-administer 6MWTs independently at home.

The association of dynamic spinal alignment on gait endurance of patients with adult spinal deformity: a cross-sectional study

PURPOSE

The purpose of this study was to evaluate the gait posture of patients with adult spinal deformity (ASD) using a 3-dimensional motion analysis system (3DMAS) and to investigate whether it affects gait endurance.

METHODS

Fifty-one patients with ASD aged 50 years or older who were admitted to our hospital between March 2016 and March 2018 were included in the study. The subjects completed the 6-min walking test, which is an indicator of gait endurance. Static standing posture was assessed by whole-spine x-ray examination (coronal cobb angle, CCA; sagittal vertical axis, SVA; pelvic tilt, PT; and pelvic incidence minus lumbar lordosis, PI-LL). In addition, the gait posture was evaluated by a 3DMAS (dynamic trunk tilt angle, DTA; and dynamic pelvic tilt angle, DPA). The relationship between standing and gait postures and gait endurance was investigated by multivariable analysis.

RESULTS

In univariable analysis, SVA, PI-LL, and DTA were associated with gait endurance. Furthermore, in the multivariable analysis, DTA showed the strongest association among the static and dynamic parameters (R² = 0.61, β = - 0.35, P < 0.05).

CONCLUSIONS

An association was found between gait posture and gait endurance in patients with ASD. These findings can be useful to health care providers treating patients with ASD. It is advisable to assess the gait posture of patients with ASD because they present postural abnormalities during gait.

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.

The reliability of VO2 kinetics during a 6-minute walking test is influenced by walk speed

[Purpose] This study aimed to investigate the reliability of time constant measurements of oxygen intake at fast and comfortable speeds during a 6-min waling test. [Participants and Methods] The study included 10 healthy young males who walked at 4.5 km/h and 6.0 km/h twice for 6 min each in speed treadmill. Breath-by-breath gas exchange data were continuously measured and used to calculate the time constant of oxygen uptake. The reproducibility and variability of the variables were verified using the limit of agreement, inter-class correlation coefficient, coefficient of variation, and standard error of measurement. [Results] The limit of agreement was −8.5 to 2.3 s and −3.9 to 2.1 s for speeds 4.5 km/h and 6.0 km/h, respectively. The inter-class correlation coefficient, coefficient of variation, and standard error of measurement of the time constant for both speeds were 0.52 and 0.83, 11.2% and 6.4%, and 5.3 s and 1.8 s, respectively. [Conclusion] The results of this study suggested that the cardiopulmonary response, in terms of oxygen uptake, was more consistent during fast walking than during comfortable walking in a 6-min walking test with constant speed.

Accompanied versus unaccompanied walking for continuous oxygen saturation measurement during 6-min walk test in COPD: a randomised crossover study

The aim of this study was to determine if there is a difference in 6-min walk test (6MWT) distance when the assessor accompanies the patient to continuously measure peripheral oxygen saturation (S_pO2) compared to the patient walking unaccompanied.

 We conducted a randomised crossover study to evaluate the impact of the assessor walking with the patient during the 6MWT (6MWT_with) versus the patient walking alone (6MWT_without). At the end of a pulmonary rehabilitation programme, each patient performed two 6MWTs in random order and separated by a 30-min rest.

 49 patients with chronic obstructive pulmonary disease (COPD) (Global Initiative for Obstructive Lung Disease classification II–IV) were included. In a regression model adjusting for period and subject, accompanying the patient resulted in a lower walking distance (mean difference −9.1 m, 95% CI −13.9– −4.3, p=0.0004). Notably, six patients walked more than 30 m farther (minimal important difference) in one of the two conditions (6MWT_with: n=1, 6MWT_without: n=5). There were no between-sequence-group differences in heart rate, dyspnoea, leg fatigue and S_pO2. The median (interquartile range) number and duration of S_pO2 signal artefacts were high but not different between the experimental conditions (6MWT_with: 17 (4–24), 34 s (7–113 s); 6 MWT_without: 11 (3–26), 24 s (4–62 s)).

 At a study population level, we observed a statistically significant difference in 6MWT distance between the two experimental conditions; however, the magnitude of difference was small and may not be clinically relevant. Nevertheless, in a clinical setting, unaccompanied walking resulted in a substantially higher walking distance in individual patients, pointing towards strictly standardised testing methodology, in particular in pre–post study designs.

Accompanied walking during a 6MWT versus unaccompanied walking results in shorter walked distance (mean difference −9.1 m, 95% CI −13.9– −4.3 m). No differences in nadir S_pO2 or oximetry artefacts were noted between accompanied and unaccompanied walking.https://bit.ly/3tBjfCq

Does 1-minute walk test predict results of 6-minute walk test in patients with idiopathic pulmonary fibrosis?

Background

The six-minute walk test (6MWT) is a readily available tool used to evaluate functional capacity in patients with idiopathic pulmonary fibrosis (IPF). However, it is often logistically challenging to perform in the context of a busy clinical practice. We sought to investigate if the 1MWT distance (1MWD) predicts the 6MWT distance (6MWD), and if an abbreviated walk could accurately predict outcomes in IPF patients.

Methods

Baseline demographics and pulmonary function testing of IPF patients evaluated at a tertiary referral center between 2010 and 2017 were collected. 6MWT variables at baseline as well as 1 and 6 minutes were collected. Time to death, lung transplantation, or most recent follow-up was ascertained.

Results

There were 177 patients, the majority of whom (80%) were male. The mean age was 67 ± 9 years and mean FVC was 64 ± 18% predicted. Forty eight (27%) patients used oxygen supplementation during the 6MWT. The median 6MWD was 366 meters (IQR: 268-471) while the median 1MWD was 65 meters (IQR: 46-81). Stratified by the median, 89 patients were "High Walkers" based on the 6MWD ≥ 366m (HW₆) and 88 patients were "Low Walkers" (LW₆). HW₆ had a higher FVC% (70 ± 15 vs 57 ± 18, p= 0.001), higher DLCO% (45 ± 12 vs 34 ± 14, p= 0.001) and higher 1MWD (83 ± 28 vs 47 ± 16, m p= 0.001). Median transplant-free survival was better in HW₆ vs LW₆ (27 ± 16 vs 22 ± 18 months, log rank p= 0.018). There was a strong correlation between the 1MWD and the 6MWD (r= 0.91, Spearman's correlation, p < 0.0001). Also, the transplant-free survival curves stratified by 1MWD were very similar to the curves for 6MWD, showing a lower survival in the LW₁ cohort (log rank p= 0.009).

Conclusion

The 1MWD obtained during the first minute of a 6MWD shows a strong correlation to total 6MWD and retains its ability to predict transplant-free survival. 1MWT may serve as a practical substitute for the more cumbersome 6MWT. Our findings require further validation prospectively in larger cohorts of IPF patients.

Effort-Based Decision-Making for Exercise in People with Parkinson's Disease

BACKGROUND

People with Parkinson's disease (PwPD) are less active than their age-matched peers. Non-motor symptoms, specifically, deficient motivation, may influence decision-making for exercise due to the impaired mesolimbic dopaminergic pathway.

OBJECTIVE

The purpose of this study was to determine if effort-based decision-making for physical effort was different in PwPD compared to healthy controls. We sought to determine the relationship between effort-based decision making for exercise and a discrete motor task as well as the impact of components of motivation on decision-making for physical effort in PwPD.

METHODS

An effort-based decision-making paradigm using a discrete motor task (button pressing) and a continuous exercise task (cycling) was implemented in 32 PwPD and 23 healthy controls. Components of motivation were measured using the Apathy Scale and the Temporal Experience of Pleasure Scale- Anticipatory Pleasure scale.

RESULTS

The presence of Parkinson's disease (PD) did not moderate decisions for either physical effort task. There was a moderate correlation between decisions for both tasks, within each group. The anticipation of pleasure and apathy were predictors of decisions for both physical effort tasks in PwPD, but not in healthy controls.

CONCLUSION

PwPD responded similarly to effort and reward valuations compared to those without PD. Individuals were consistent in their decisions, regardless of the physical effort task. The anticipation of pleasure and apathy were significant predictors of decisions for exercise in PwPD only. Increased anticipation of pleasure, reduction of apathy, and the use of rewards may enhance engagement in high effort exercise among PwPD.

Standardization of the 6-min walk test in clinical trials of idiopathic pulmonary fibrosis

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

BACKGROUND

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.

METHODS

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).

RESULTS

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.

CONCLUSIONS

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.

[Late phase II/III study of BYM338 in patients with sporadic inclusion body myositis (RESILIENT): Japanese cohort data]

A global, randomized, double-blind placebo-controlled study was conducted to confirm that BYM338 (bimagrumab), an anti-activin type II receptor antibody, improves motor function in patients with sporadic inclusion body myositis after 52 weeks' treatment consisting of intravenous administration every 4 weeks at doses of 10, 3, and 1 mg/kg. In a Japanese sub-population (20 patients in total, 5 per dose group), no significant differences in the change from baseline of the 6-minute walking distance at Week 52 (primary endpoint) were observed between the placebo group and each BYM338 dose group. Furthermore, the lean body mass as an indicator of skeletal muscle mass increased in all BYM338 groups compared with the placebo group and the effects were dose-dependent. Overall, the Japanese sub-population showed similar trends as observed in the entire population (251 patients in total).

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.

Functional Capacity Evaluation in Different Societal Contexts: Results of a Multicountry Study

Purpose To examine factors associated with Functional Capacity Evaluation (FCE) results in patients with painful musculoskeletal conditions, with focus on social factors across multiple countries. Methods International cross-sectional study was performed within care as usual. Simple and multiple multilevel linear regression analyses which considered measurement's dependency within clinicians and country were conducted: FCE characteristics and biopsychosocial variables from patients and clinicians as independent variables; and FCE results (floor-to-waist lift, six-minute walk, and handgrip strength) as dependent variables. Results Data were collected for 372 patients, 54 clinicians, 18 facilities and 8 countries. Patients' height and reported pain intensity were consistently associated with every FCE result. Patients' sex, height, reported pain intensity, effort during FCE, social isolation, and disability, clinician's observed physical effort, and whether FCE test was prematurely ended were associated with lift. Patient's height, Body Mass Index, post-test heart-rate, reported pain intensity and effort during FCE, days off work, and whether FCE test was prematurely ended were associated with walk. Patient's age, sex, height, affected body area, reported pain intensity and catastrophizing, and physical work demands were associated with handgrip. Final regression models explained 38‒65% of total variance. Clinician and country random effects composed 1-39% of total residual variance in these models. Conclusion Biopsychosocial factors were associated with every FCE result across multiple countries; specifically, patients' height, reported pain intensity, clinician, and measurement country. Social factors, which had been under-researched, were consistently associated with FCE performances. Patients' FCE results should be considered from a biopsychosocial perspective, including different social contexts.

Utility of the six-minute walk test in patients with idiopathic pulmonary fibrosis

The six-minute walk test (6MWT) is a simple test that is widely used to assess functional exercise capacity in patients with idiopathic pulmonary fibrosis (IPF). Patients with IPF have reduced exercise capacity due to a number of factors, such as impaired respiratory mechanics and circulatory problems. As a self-paced and usually submaximal exercise test, the 6MWT reflects the exercise level of everyday activities. Variables measured during the 6MWT, such as six-minute walk distance (6MWD) and desaturation, are strong predictors of mortality in patients with IPF. However, the results of a 6MWT are affected by numerous factors, including age, body size, comorbidities and the use of supplemental oxygen during the test, and these need to be borne in mind when interpreting the results of individual and serial tests. Clinical studies, including trials of potential therapies for IPF, have differed in the methodology used to implement the 6MWT, hindering the comparison of results across studies. In this review, I describe the utility of the 6MWT in patients with IPF and provide recommendations for standardisation of the test for use both in clinical practice and research. A brief video on how to set up and administer the 6MWT is available at http://www.usscicomms.com/respiratory/lancaster/6mwt/

Learning and Encouragement Effects on Six-Minute Walking Test in Children

OBJECTIVES

To evaluate learning and encouragement effects on the 6-minute walk test in children between 6 and 12 years of age.

STUDY DESIGN

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.

RESULTS

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).

CONCLUSION

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.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03276299.

Association between social factors and performance during Functional Capacity Evaluations: a systematic review

Purpose: Determine the association of different social factors with Functional Capacity Evaluation (FCE) performance in adults. Materials and methods: A systematic literature search was performed in MEDLINE, CINAHL, and PsycINFO electronic databases. Studies were eligible if they studied social factor's association with the performance of adults undergoing FCE. Studies were assessed on methodological quality and quality of evidence. The review was performed using best-evidence synthesis methods. Results: Thirteen studies were eligible and 11 social factors were studied. Considerable heterogeneity regarding measurements, populations, and methods existed among the studies. High quality of evidence was found for the association of FCE performance with the country of FCE and examiner's fear behavior; moderate quality of evidence with previous job salary; and low or very low quality of evidence with compensation status, litigation status, type of instruction, time of day (workday), primary or mother language, and ethnicity. Other social factors were not studied. Conclusions: Evidence for associations of various social factors with FCE performance was found, but robust conclusions about the strength of the associations cannot be made. Quality of evidence ranged from high to very low. Further research on social factors, also within a biopsychosocial context, is necessary to provide a better understanding of FCE performance. Implications for Rehabilitation Research on Functional Capacity Evaluation (FCE) performance and its association with biopsychosocial factors have scarcely addressed the impact of social factors, limiting full understanding of FCE results. The social factors, healthcare (examiner's fear behavior and type of instruction), personal or cultural systems (country of FCE, primary or mother language, and ethnicity), workplace system (previous job salary, time of day (workday)), and legislative and insurance system (compensation and litigation status), have a bearing in FCE performance. Better understanding of factors associating with functional capacity provide insights in FCE, allowing clinicians to improve the evaluations and interpretations of the assessment and better design the rehabilitation program. Better understanding of factors that influence FCE performance, and of unstudied factors, will allow researchers guidance to further investigate the construct of functional capacity.

High-Velocity Quadriceps Exercises Compared to Slow-Velocity Quadriceps Exercises Following Total Knee Arthroplasty: A Randomized Clinical Study

BACKGROUND AND PURPOSE

Despite improvement in pain and perceived function in older adults following total knee arthroplasty (TKA), objective outcome measures of muscular impairment and ambulatory function demonstrate significant deficits. Evidence suggests that quadriceps power may play a greater role in ambulatory function than measures of strength alone following TKA. The purpose of this study was to compare the effect of high-velocity (HV) quadriceps exercises with that of slow-velocity (SV) quadriceps exercises on functional outcomes and quadriceps power following TKA.

METHODS

This study was a randomized clinical study conducted in an outpatient physical therapy clinic. Twenty-one participants who were 4 to 6 weeks post unilateral TKA were randomly assigned to an HV or SV group. Participants performed an evidence-based standardized progressive resistance exercise program in addition to HV quadriceps exercises or SV quadriceps exercises. Participants attended 2 sessions per week for 8 weeks. Before and after the 8-week exercise intervention, participants completed a functional questionnaire, health survey, functional testing, and underwent quadriceps strength and power testing.

RESULTS

Both groups demonstrated improvements in ambulatory outcome measures, strength, speed, and power. The HV group demonstrated significantly greater improvements in distance walked and quadriceps strength than the SV group.

LIMITATIONS

These data should be considered preliminary because of a small sample size.

CONCLUSION

HV quadriceps exercises may be an effective rehabilitation strategy in conjunction with a standardized progressive resistance exercise program beginning 4 to 6 weeks after TKA.

Feasibility and Reliability of Tests Measuring Health-Related Physical Fitness in Children With Moderate to Severe Levels of Intellectual Disability

Physical fitness is an important marker for health. In this study we investigated the feasibility and reliability of health-related physical fitness tests in children with moderate to severe levels of intellectual disability. Thirty-nine children (2-18 yrs) performed tests for muscular strength and endurance, the modified 6-minute walk test (6mwt) for cardiorespiratory fitness, and body composition tests, and 30-97% of the tests were successfully completed. Short-term test-retest reliability of all tests was good (Intraclass Correlation Coefficient [ICC] > .8), long-term test-retest reliability was good for most tests (ICC > .7), but low ICCs were found for most strength tests. Measuring body composition and cardiorespiratory fitness is feasible and reliable. Measuring muscle endurance is fairly feasible and reliable.

Relation of Longitudinal Changes in Quality of Life Assessments to Changes in Functional Capacity in Patients With Heart Failure With and Without Anemia

Clinical status in heart failure is conventionally assessed by the physician's evaluation, patients' own perception of their symptoms, quality of life (QoL) tools, and a measure of functional capacity. These aspects can be measured with tools such as the New York Heart Association functional class, QoL tools such as the EuropeanQoL-5 dimension, the Kansas City Cardiomyopathy Questionnaire, patient global assessment (PGA), and by 6-minute walk test (6MWT), respectively. The ferric carboxymaltose in patients with heart failure and iron deficiency (FAIR-HF) trial demonstrated that treatment with intravenous ferric carboxymaltose in iron-deficient patients with symptomatic heart failure with reduced left ventricular function, significantly improved all 5 outcome measures. This analysis assessed the correlations between the longitudinal changes in the measures of clinical status, as measured by QoL tools and the changes in the measures of functional capacity as measured by the 6MWT. This analysis used the database from the FAIR-HF trial, which randomized 459 patients with chronic heart failure (reduced left ventricular ejection fraction) and iron deficiency, with or without anemia to ferrous carboxymaltose or placebo. The degree of correlation between QoL tools and the 6MWT was assessed at 4, 12, and 24 weeks. The data demonstrate highly significant correlations between QoL and functional capacity, as measured by the 6MWT, at all time points (p <0.001). Changes in PGA, Kansas City Cardiomyopathy Questionnaire, and EuroQoL-5D correlated increasingly over time with changes in 6MWT performance. Interestingly, the strongest correlation at 24 weeks is for the PGA, which is a simple numerical scale (r = -0.57, p <0.001). This analysis provides evidence that QoL assessment show a significant correlation with functional capacity, as measured by the 6MWT. The strength of these correlations increased over time.

Periodic sound-based 6-minute walk test forpatients with Duchenne muscular dystrophy:a preliminary study

[Purpose] The purpose of this study was to verify if a periodic sound-based 6-minute walk test with the best periodic sound could be used to evaluate physical endurance more precisely than the conventional 6-minute walk test. [Subjects] The subjects were healthy subjects and 6 ambulant patients with Duchenne muscular dystrophy. [Methods] The subjects initially walked for 1 minute to a long-interval metronome sound, and the walking distance was measured. The sound interval was then gradually shortened, and the subjects walked for 1 minute for each of the intervals. The best periodic sound was considered to be the periodic sound used when the subject walked the longest distance in 1 minute, and the process of determining it was referred to as the period shortening walk test. This study administered the 6-minute walk test with the best periodic sound to twenty healthy subjects and 6 ambulant patients with Duchenne muscular dystrophy and compared the walking distance. [Results] The periodic sound-based 6-minute walk test distances in both the healthy subjects and the patients were significantly longer than the conventional 6-minute walk test distances. [Conclusion] The periodic sound-based 6-minute walk test provided a better indication of ambulatory potential in an evaluation of physical endurance than the conventional 6-minute walk test.

Protocol for a mixed-methods study of supplemental oxygen in pulmonary fibrosis

BACKGROUND

Little is known about whether or how supplemental oxygen affects patients with pulmonary fibrosis.

METHODS/DESIGN

A mixed-methods study is described. Patients with pulmonary fibrosis, informal caregivers of pulmonary fibrosis patients and practitioners who prescribe supplemental oxygen will be interviewed to gather data on perceptions of how supplemental oxygen impacts patients. In addition, three hundred pulmonary fibrosis patients who do not use daytime supplemental oxygen will be recruited to participate in a longitudinal, pre-/post- study in which patient-reported outcome (PRO) and activity data will be collected at baseline, immediately before daytime supplemental oxygen is initiated, and then once and again 9-12 months later. Activity data will be collected using accelerometers and portable GPS data recorders. The primary outcome is change in dyspnea from before to one month after supplemental oxygen is initiated. Secondary outcomes include scores from PROs to assess cough, fatigue and quality of life as well as the activity data. In exploratory analyses, we will use longitudinal data analytic techniques to assess the trajectories of outcomes over time while controlling for potentially influential variables.

DISCUSSION

Throughout the study and at its completion, results will be posted on the website for our research program (the Participation Program for Pulmonary Fibrosis or P3F) at http://www.pulmonaryfibrosisresearch.org.

An official European Respiratory Society/American Thoracic Society technical standard: field walking tests in chronic respiratory disease

Field walking tests are commonly employed to evaluate exercise capacity, assess prognosis and evaluate treatment response in chronic respiratory diseases. In recent years, there has been a wealth of new literature pertinent to the conduct of the 6-min walk test (6MWT), and a growing evidence base describing the incremental and endurance shuttle walk tests (ISWT and ESWT, respectively). The aim of this document is to describe the standard operating procedures for the 6MWT, ISWT and ESWT, which can be consistently employed by clinicians and researchers. The Technical Standard was developed by a multidisciplinary and international group of clinicians and researchers with expertise in the application of field walking tests. The procedures are underpinned by a concurrent systematic review of literature relevant to measurement properties and test conduct in adults with chronic respiratory disease. Current data confirm that the 6MWT, ISWT and ESWT are valid, reliable and responsive to change with some interventions. However, results are sensitive to small changes in methodology. It is important that two tests are conducted for the 6MWT and ISWT. This Technical Standard for field walking tests reflects current evidence regarding procedures that should be used to achieve robust results.

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.

Treatment of pulmonary hypertension in idiopathic pulmonary fibrosis: shortfall in efficacy or trial design?

Idiopathic pulmonary fibrosis (IPF) is a disease that carries a high mortality. Pulmonary hypertension (PH) frequently complicates the course of patients with IPF and is associated with significantly worse outcomes. Whether PH is a surrogate or driver of these worse outcomes remains unanswered, but the presence of PH represents an attractive target for therapy. This review delves into the various pulmonary vasoactive agents that have been subjected to study in IPF, the pitfalls of some of these prior studies, and attempts to lay a foundation for future study designs targeting PH in IPF.