Feasibility, criterion and construct convergent validity of the 2-minute walk test and the 10-meter walk test in an oncological context

Objective

To examine the feasibility, the criterion, and the construct convergent validity of the 2-Minute Walk Test (2MWT) and the 10-Meter Walk Test (10MeWT) against the 6-Minute Walk Test (6MWT) to assess walking capacity in people with cancer. The criterion concurrent validity of a self-test version of the 10MeWT (10MeWTself-test) was also evaluated against the 10MeWT.

Methods

Fifty-six people with cancer performed the 2MWT, the 10MeWT at comfortable and fast speeds, the 6MWT, and the 10MeWTself-test. The feasibility of the tests was assessed using safety, adverse events, space requirements, time taken to administer and interpret the tool, equipment or training required, cost, and portability as criteria. Validity was assessed using Pearson correlation coefficients and Bland Altman plots.

Results

The 2MWT, 6MWT, 10MeWT, and 10MeWTself-test were feasible for people with cancer. The 2MWT and the 10MeWT results were moderately to strongly correlated with the 6MWT results (0.61 < r < 0.84, p < 0.001). The 10MeWTself-test results were strongly correlated with the 10MeWT results at comfortable and fast speeds (r = 0.99, p < 0.001).

Conclusions

The 2MWT, 10MeWT, and 10MeWTself-test are simple, rapid, and feasible tests for use in people with cancer. The strong correlation between the 2MWT and 6MWT results indicates that the 2MWT can be used as an alternative walking capacity assessment tool. The 10MeWT results moderately correlated with those of the other two tests, suggesting that it partially measures the same construct of walking capacity in walking-independent outpatients with cancer. The 10MeWTself-test showed promising results but needs further investigations in ecological settings.

The correlates and reference values for the 6-minute walk distance in Taiwanese adults with schizophrenia

PURPOSE

The study aimed to identify the factors associated with the 6-min walk distance (6MWD) and to provide reference values for the 6MWD in individuals with schizophrenia (SCZ) in Taiwan.

METHODS

A proportional stratified sampling method was utilized based on distribution of gender, age and body mass index (BMI) at the study hospital. The 6-minute walk test was conducted according to the American Thoracic Society protocol.

RESULTS

A total of 237 patients with SCZ completed the 6-minute walk test. The 6MWD was significantly associated with age, height, weight, and length of the onset of SCZ. Stepwise linear regression revealed that height and age were significant determinants of 6MWD. The reference values for males and females at different age groups were determined. Notably, females over 60 walked substantially shorter than the age younger than 60.

CONCLUSIONS

Height and age were the main predictors for 6MWD among people with SCZ in Taiwan. The established reference values can be used to identify those at risk of poor cardiorespiratory fitness and as a target outcome during exercise programs in psychiatric rehabilitation. Our results highlight that older females with SCZ may be a priority group to target with exercise interventions to mitigate the faster decline in cardiorespiratory fitness.IMPLICATIONS FOR REHABILITATIONHeight and age were predictors of 6-min walk distance (6MWD) in schizophrenia (SCZ).The established age- and gender reference values for the 6MWD can be used to identify those at risk of poor cardiorespiratory fitness.Females with SCZ over age 60 may be a priority group to target with exercise interventions to mitigate the faster decline in cardiorespiratory fitness.

Effect of prehabilitation on patients with frailty undergoing colorectal cancer surgery: a systematic review and meta-analysis

Purpose

The effect of prehabilitation in patients with frailty undergoing colorectal cancer surgery remains controversial. This meta-analysis aimed to assess the impact of prehabilitation before colorectal surgery on the functional outcomes and postoperative complications in patients with frailty undergoing colorectal cancer surgery.

Methods

PubMed, EMBASE, Cochrane Library, and Scopus databases were searched for articles published up to November 9, 2022. We included randomized and non-randomized trials in which the effects of prehabilitation in patients with frailty undergoing colorectal cancer surgery were investigated against a control group. Data extracted for our meta-analysis included the 6-minute walk test (6MWT), postoperative incidence of complications (Clavien-Dindo classification ≥IIIa), comprehensive complication index (CCI), and length of stay (LOS) in the hospital.

Results

Compared with the control group, we found a significant improvement in the incidence of postoperative complications and shorter LOS in the hospital in the prehabilitation group. However, the 6MWT and CCI results showed no significant differences between the 2 groups.

Conclusion

Prehabilitation in patients with frailty who underwent colorectal cancer surgery improved the incidence of postoperative complications and LOS in the hospital. Hence, clinicians should consider conducting or recommending prehabilitation exercises prior to colorectal cancer surgery in patients with frailty.

Validity and clinical applicability of the 60-secondecond sit-to-stand test in people with acute exacerbations of COPD

BACKGROUND

The 60-second sit-to-stand test (60STS) is a simple and increasingly popular test of physical function, however evidence to support its appropriateness for assessing people with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is lacking.

AIMS

To evaluate the concurrent, convergent, predictive and discriminant validity, and responsiveness of the 60STS against the six-minute walk test (6MWT) in people hospitalised due to AECOPD.

METHODS

Prospective cohort study involving 54 inpatients with AECOPD (53% males, mean age 69.0 years, FEV1 46.5% predicted). 60STS was performed 30 min after a six-minute walk test (6MWT) upon discharge, with follow-up testing repeated one-month later (n = 39). Outcome measures included 60STS repetitions (60STSr), six-minute walk distance (6MWD), heart rate, oxyhaemoglobin saturation (SpO2), perceived dyspnoea (Borg scale), and rate of perceived exertion (RPE). Concurrent validity was assessed via correlation, convergent validity via Bland-Altman plots, predictive validity via multivariate linear regression (adjusted for confounders), discriminant validity via unpaired t tests and responsiveness via Chi (Jenkins, 2007) [2] tests.

RESULTS

Discharge 60STSr and 6MWD were strongly correlated (r = 0.61). Bland-Altman plots for nadir SpO2, peak HR, Borg and RPE scores showed acceptable agreement in terms of mean differences, but wide limits of agreement. Poor 60STSr performers were older, had weaker quadriceps, and had lower 6MWD than high performers (p < 0.05 for all). 60STSr was not retained as a significant predictor of 6MWD in multivariate regression analyses. 80% of 60STSr improvers also improved >30m on 6MWT at follow-up.

CONCLUSION

The 60STS demonstrates satisfactory validity and responsiveness as a measure of exercise performance in people with AECOPD.

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

SUMMARY AT A GLANCE

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

ETHICS APPROVAL

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Agreement between heart rate at first ventilatory threshold on treadmill and at 6-min walk test in coronary artery disease patients on β-blockers treatment

The purpose of this study was to verify the accuracy of the agreement between heart rate at the first ventilatory threshold (HR_VT1) and heart rate at the end of the 6-min walk test (HR_6MWT) in coronary artery disease (CAD) patients on β-blockers treatment. This was a cross-sectional study with stable CAD patients, which performed a cardiopulmonary exercise test (CPET) on a treadmill and a 6-min walk test (6MWT) on nonconsecutive days. The accuracy of agreement between HR_VT1 and HR_6MWT was evaluated by Bland–Altman analysis and Lin’s concordance correlation coefficient (r_c), mean absolute percentage error (MAPE), and standard error of estimate (SEE). Seventeen stable CAD patients on β-blockers treatment (male, 64.7%; age, 61±10 years) were included in data analysis. The Bland–Altman analysis revealed a negative bias of −0.41±6.4 bpm (95% limits of agreements, −13 to 12.2 bpm) between HR_VT1 and HR_6MWT. There was acceptable agreement between HR_VT1 and HR_6MWT (r_c=0.84; 95% confidence interval, 0.63 to 0.93; study power analysis=0.79). The MAPE of the HR_6MWT was 5.1% and SEE was 6.6 bpm. The ratio HR_VT1/HR_peak and HR_6MWT/HR_peak from CPET were not significantly different (81%±5% vs. 81%±6%, P=0.85); respectively. There was a high correlation between HR_VT1 and HR_6MWT (r=0.85, P<0.0001). Finally, the results of the present study demonstrate that there was an acceptable agreement between HR_VT1 and HR_6MWT in CAD patients on β-blockers treatment and suggest that HR_6MWT may be useful to prescribe and control aerobic exercise intensity in cardiac rehabilitation programs.

Effects of supervised exercise therapy on blood pressure and heart rate during exercise, and associations with improved walking performance in peripheral artery disease: Results of a randomized clinical trial

OBJECTIVE

Supervised exercise therapy (SET) improves walking ability in people with peripheral artery disease (PAD). However, the effects of SET on cardiovascular health in PAD remain unclear. Using data from a randomized clinical trial, this post hoc analyses investigated the effects of a 6-month SET intervention, compared with a control group, on changes in blood pressure (BP) and heart rate (HR) during a graded treadmill exercise test in people with PAD.

METHODS

We randomized 210 participants with PAD to either SET (3× weekly) or control (1× weekly health lectures) for 6 months. A graded treadmill exercise test, 6-minute walk test, and Walking Impairment Questionnaire were completed at baseline and the 6-month follow-up. BP and HR were measured at the end of each 2-minute stage of the graded treadmill exercise test. Mixed effects regression models compared the overall mean 6-month change in systolic BP, diastolic BP, pulse pressure (PP), and HR during the first 5 stages of the graded treadmill exercise test between groups.

RESULTS

Of the 210 randomized participants with PAD, 176 (67 ± 9 years; 72 [41%] female, 115 [65%] Black) completed the graded treadmill exercise test at baseline and the 6-month follow-up. Compared with the control group at the 6-month follow-up, SET significantly decreased overall mean systolic BP (-12 mm Hg; P < .001), PP (-9 mm Hg; P < .001), and HR (-7 b/min; P < .01) during a graded treadmill exercise test but not diastolic BP. Among participants randomized to SET, a greater decrease in systolic BP, PP, and HR during a graded treadmill exercise test was significantly associated with a greater improvement in 6-minute walk distance (systolic BP, r = -0.19 [P = .03] and PP, r = -0.23 [P < .01]; and HR, r = -0.21 [P < .01]) and with maximal treadmill walking distance (systolic BP, r = -0.21 [P < .01] and PP, r = -0.17 [P = .03]) at the 6-month follow-up. A greater decrease in the HR during a graded treadmill exercise test was significantly associated with a better WIQ distance score (r = -0.27; P = .03) at the 6-month follow-up.

CONCLUSIONS

In people with PAD, compared with a control group, SET improved cardiovascular health, measured by changes in BP and HR during exercise. The degree of improvement in cardiovascular health correlated with the degree of improvement in walking performance in people with PAD. NCT: 01408901.

Pulmonary function and functional capacity in COVID-19 survivors with persistent dyspnoea

The purpose of this study was to examine the physiological mechanisms of persistent dyspnoea in COVID-19 survivors. Non-critical patients (n = 186) with varying degrees of COVID-19 severity reported persistent symptoms using a standardized questionnaire and underwent pulmonary function and 6-minute walk testing between 30 and 90 days following the onset of acute COVID-19 symptoms. Patients were divided into those with (n = 70) and without (n = 116) persistent dyspnoea. Patients with persistent dyspnoea had significantly lower FVC (p = 0.03), FEV₁ (p = 0.04), D_LCO (p = 0.01), 6-minute walk distance (% predicted, p = 0.03), and end-exercise oxygen saturation (p < 0.001), and higher Borg 0-10 ratings of dyspnoea and fatigue (both p < 0.001) compared to patients without persistent dyspnoea. We have shown that dyspnoea is a common persistent symptom across varying degrees of initial COVID-19 severity. Patients with persistent dyspnoea had greater restriction on spirometry, lower D_LCO, reduced functional capacity, and increased exertional desaturation and symptoms. This suggests that there is a true physiological mechanism that may explain persistent dyspnoea after COVID-19.

Assessing Preoperative Mobility in Total Hip Arthroplasty: A SAFE T database study

This study examined whether individuals undergoing total hip arthroplasty who are self-rated as "highly active", demonstrated higher pre-operative activity levels than others.

Methods

483 patients were retrospectively identified; 241 were "highly active" and 242 were not. They were compared using WOMAC, self-reported activity and 6-Minute Walk Test (6MWT).

Results

Self-reported highly active adults demonstrated statistically significant higher WOMAC scores (48.85 vs 43.79), increased mean number of activities performed and mean 6MWT (348.14 m vs 274.64 m).

Conclusions

The positive correlation between subjective and objective measures of mobility increase our confidence in the latter as valid indicator of patient's preoperative activity level.

Decompression surgery improves gait quality in patients with symptomatic lumbar spinal stenosis

BACKGROUND CONTEXT

We aimed to fully understand the extent of limitations associated with symptomatic lumbar spinal stenosis (LSS) and the functional outcome of its treatment, including not only function during daily activities (eg, using the 6-minute walk test [6MWT]) but also the quality of function that should be objectively assessed.

PURPOSE

This study was performed to test the hypothesis that the Oswestry Disability Index (ODI) score, the walking distance during the 6MWT (6-minute walking distance [6MWD]), and gait quality (spatiotemporal parameters and gait asymmetry) will improve postoperatively and achieve normal values; to determine if changes in gait parameters correlate with changes in Oswestry Disability Index (ODI) score; and to ascertain if patients' gait quality will diminish during the 6MWT, reflected by changes in gait parameters during the 6MWT.

STUDY DESIGN/SETTING

This is a prospective observational study with intervention.

PATIENT SAMPLE

The sample comprised patients with symptomatic LSS.

OUTCOME MEASURES

The ODI score, gait quality (spatiotemporal and asymmetry), and walking performance (walking distance during the 6MWT) were the outcome measures.

METHODS

Patients with symptomatic LSS were analyzed on the day before surgery and 10 weeks and 12 months postoperatively. Functional disability in daily life was assessed by the ODI. Spatiotemporal and kinematic gait parameters were recorded with an inertial sensor system during the 6MWT, and the 6MWD was determined. Gait asymmetry was defined as 100*|right-left|/(0.5*(|right+left|)).

RESULTS

The ODI decreased by 17.9% and 23.9% and 6MWD increased by 21 m and 26 m from baseline to 10-week and 12-month follow-up, respectively. Gait quality did not change during the 6MWT at any assessment or between assessments. Compared with the control group, patients walked less during the 6MWT, and gait quality differed between patients and the control group at baseline and 10-week follow-up but not at 12-month follow-up. Change in gait quality explained 39% and 73% of variance in change in ODI from baseline to 10-week and to 12-month follow-up, respectively.

CONCLUSIONS

Changes in gait quality explained a large portion of variance in changes in the ODI, indicating that patients with symptomatic LSS perceive their compromised gait quality as functional limitations. Gait data obtained by instrumented gait analysis contain information on gait quality that can be helpful for evaluating functional limitations in patients with LSS, the outcome of decompression surgery, and the development of patient-specific rehabilitation regimens.

Supplementation with Qter® and Creatine improves functional performance in COPD patients on long term oxygen therapy

BACKGROUND

Skeletal muscle dysfunction and poor functional capacity are important extra-pulmonary manifestations of chronic obstructive pulmonary disease (COPD), especially in COPD patients on long-term O₂ therapy (LTOT). Beside the role of pulmonary rehabilitation, the effect of nutritional interventions is still controversial, and there are knowledge gaps on the effective role of nutraceutical supplementation on hard endpoints. The aim of this study was to investigate the effects of nutritional supplementation with Coenzyme Q10 (QTer^®) - a powerful antioxidant with the potential to reduce oxidative stress and improve mitochondrial function - and Creatine on functional, nutritional, and metabolomic profile in COPD patients on long-term O₂ therapy.

METHODS

One-hundred and eight patients with COPD from 9 Italian hospitals were enrolled in this double-blinded randomized placebo-controlled clinical study. At baseline and after 2 months of therapy, the patients underwent spirometry, 6-minute walk test (6MWT), bioelectrical impedance analysis, and activities of daily living questionnaire (ADL). Also, dyspnea scores and BODE index were calculated. At both time points, plasma concentration of CoQ10 and metabolomic profiling were measured.

FINDINGS

Ninety patients, who randomly received supplementation with QTer^® and Creatine or placebo, completed the study. Compared with placebo, supplemented patients showed improvements in 6MWT (51 ± 69 versus 15 ± 91 m, p < 0.05), body cell mass and phase angle, sodium/potassium ratio, dyspnea indices and ADL score. The CoQ10 plasma concentration increased in the supplementation group whereas it did not change in the placebo group. The metabolomics profile also differed between groups. Adverse events were similar in both groups.

INTERPRETATION

These results show that in patients with COPD, dietary supplementation with CoQ10 and Creatine improves functional performance, body composition and perception of dyspnea. A systemic increase in some anti-inflammatory metabolites supports a pathobiological mechanism as a reason for these benefits. Further trials should help clarifying the role of QTer^® and Creatine supplementation in patients with COPD.

Influence of riociguat treatment on pulmonary arterial hypertension : A meta-analysis of randomized controlled trials

BACKGROUND

Riociguat treatment might be beneficial for pulmonary arterial hypertension. However, the results of studies to date are controversial. We conducted a systematic review and meta-analysis to explore the influence of riociguat treatment on pulmonary arterial hypertension.

METHODS

The PubMed, Embase, Web of science, EBSCO, and Cochrane Library databases were systematically searched. Randomized controlled trials (RCTs) assessing the effect of riociguat treatment on pulmonary arterial hypertension were included. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. This meta-analysis was performed using the random effects model.

RESULTS

Seven RCTs were included in the meta-analysis. Compared with a control intervention in pulmonary arterial hypertension, riociguat treatment was able to substantially improve results of the six-minute walking distance (6-MWD; standardized mean difference [SMD] = 0.53; 95% CI = 0.36-0.69; p < 0.00001), EQ-5D score (SMD = 0.35; 95% CI = 0.15-0.54; p = 0.0005), and cardiac index (SMD = 0.94; 95% CI = 0.59-1.29; p < 0.00001). The Living With Pulmonary Hypertension (LPH) score (SMD = -0.33; 95% CI = -0.50--0.17; p < 0.0001) and pulmonary vascular resistance (PVR; SMD = -0.88; 95% CI = -1.05--0.70; p < 0.00001) were significantly reduced after riociguat treatment. There was no increase in adverse events with riociguat treatment compared with the control intervention (RR = 1.04; 95% CI = 0.98-1.09; p = 0.19).

CONCLUSION

Riociguat treatment for pulmonary arterial hypertension led to a significant increase in the 6‑MWD, EQ-5D score, and cardiac index, as well as a decrease in LPH score and PVR.

The 6MWT as a prognostic tool in pulmonary arterial hypertension: results from the COMPERA registry

BACKGROUND

In patients with pulmonary arterial hypertension, the 6-Minute Walk Test (6MWT) is recommended for risk stratification and follow-up by all guidelines. However, the prognostic value of the 6MWT has been discussed controversially. We sought to compare and validate all published 6MWT cut-off points.

METHODS

From the Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA)-registry we identified 2391 patients with pulmonary arterial hypertension who had at least one documented 6MWT measurement. A Medline search identified a total of 21 different threshold values for either single-point or change of 6MWT. All values were tested individually for prognostication of 1-year, 2-year and 3-year all-cause mortality.

RESULTS

The highest positive likelihood ratio was a cut-off value < 165 ms, whereas the best negative likelihood ratio was found to be a threshold of 440 ms. Furthermore, improvement in 6MWT had considerably less predictive value on mortality and survival than deterioration. Moreover, absolute single-point values outperformed change values for both improvement and worsening.

CONCLUSION

Our data confirmed the prognostic relevance of the 6MWT and support the cut-off values stated in most recent guidelines. Furthermore, these results explain why changes in 6MWT did not correlate consistently with prognosis in previous studies.

Effect of Body Position, Exercise, and Sedation on Estimation of Pulmonary Artery Pressure in Dogs with Degenerative Atrioventricular Valve Disease

Background

Severity of pulmonary hypertension (PH) in dogs is related to clinical signs and prognosis.

Hypothesis/Objectives

We hypothesized that Doppler echocardiographic (DE) indices of pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) are influenced by independent factors that create clinically important variability of DE‐based estimates of PH in dogs.

Animals

Thirty‐eight client owned dogs with naturally acquired degenerative atrioventricular valve disease and tricuspid regurgitation (TR).

Methods

Dogs were prospectively enrolled, and target variables were acquired during 4 echocardiographic study periods (lateral recumbency, standing, lateral recumbency after a 6‐minute walk test [6MWT], and lateral recumbency after sedation with butorphanol 0.25 mg/kg IM). Statistical methods included repeated measures ANOVA, mixed model analysis, and Chi‐squared test of association.

Results

There was a significant increase in peak TR flow velocity (TRFV; P < 0.01) after sedation in 78% of dogs, with TRFV increasing by >0.4 m/s in 42% of dogs, independent of stroke volume. A significant effect of study period on DE‐estimated PVR was not found (P = 0.15). There were negligible effects of sonographer, body position, and 6MWT on echocardiographic variables of PH. Clinically relevant cyclic variation of TRFV was found. There was an association between estimation of right atrial pressure based on subjective assessment and estimation based on cranial vena cava collapsibility (P = 0.03).

Conclusions and Clinical Importance

The increase in TRFV observed with sedation could change assessment of PH severity and impact prognostication and interpretation of treatment response. Further studies with invasive validation are needed.

Functional exercise capacity and lung function in patients undergoing an early rehabilitation program after the Nuss procedure: a randomized controlled trial

PURPOSE

The aim of this study was to compare the functional exercise capacity and the lung function among patients undergoing early rehabilitation with those submitted to the conventional care after pectus excavatum repair using the Nuss procedure.

METHOD

Patients were randomly allocated to the early rehabilitation group (ERG) who started rehabilitation after surgery and the group of the conventional care (CG) received routine care of the institution. They were evaluated before surgery (preoperative) and in hospital discharge day (postoperative).

RESULTS

Forty patients were evaluated, twenty in each group. All patients presented a significant reduction in FVC, FEV1, and PEF in the postoperative period, there was no statistically significant difference between groups. There was significant different in postoperative functional exercise capacity between the ERG and CG (506.26 ± 66.54 vs 431.11 ± 75.61, p = 0.02) and the difference between distance walked in the preoperative and postoperative period was lower in the ERC than in the CG (76.57 ± 49.41 vs 166.82 ± 70.13, p < 0.001).

CONCLUSION

Patients undergoing the early rehabilitation after the Nuss procedure presented a better postoperative functional exercise capacity in hospital discharge day compared with patients in the conventional group, with no difference in lung function between groups.

Peak Jump Power Reflects the Degree of Ambulatory Ability in Patients with Mitochondrial and Other Rare Diseases

Metabolic diseases that lead to neuromuscular, bone, and joint involvement can reduce ambulation and quality of life. Using jumping mechanography, we developed a novel assessment, peak jump power (PJP), and related this to ambulatory ability in patients either having a known or suspected underlying rare disease. From adults and children, we recruited 88 healthy controls and 115 patients (61 with mitochondrial disease and 54 with another diagnosis). Patients were categorized as having no complaints of weakness or ambulation (ambulatory competent; AC), weakness but able to ambulate without aids (ambulatory weakness; AW), or not able to ambulate without aids such as a walker, cane, or wheelchair (ambulatory assistance; AA). Subjects were asked to perform five successive jumps from a squat position. Instantaneous power (W; watts) was calculated and the highest result was divided by the body mass (kg) to calculate PJP (W/kg). Between healthy controls and AC patients, there was no difference in mean PJP (20.5 ± 7.0 W/kg vs. 19.0 ± 7.4 W/kg, p = 0.601; mean ± SD). Progressively lower results were found in patients with AW with a mean PJP of 11.7 ± 5.1 W/kg (p < 0.001 versus AC) and further those with AA with a mean PJP of 5.8 ± 3.2 W/kg (p < 0.001 versus AW). A subgroup analysis of subjects showed that those who did not use ambulatory aids all had a PJP above 10 W/kg. Using this threshold, the receiver operating characteristic curve (ROC) analysis showed PJP to be highly sensitive evaluation of ambulatory ability (sensitivity 95.8%, specificity 52.1%).

COPD patients with severe diffusion defect in carbon monoxide diffusing capacity predict a better outcome for pulmonary rehabilitation

PURPOSE

The aim of this study was to compare the effects of pulmonary rehabilitation (PR) on six-minute walk test (6mWT) between chronic obstructive pulmonary disease (COPD) patients with moderate or severe carbon monoxide diffusion defects. We also evaluated dyspnea sensation, pulmonary functions, blood gases analysis, quality of life parameters and psychological symptoms in both groups before and after pulmonary rehabilitation.

METHODS

Patients with COPD underwent a comprehensive 8-week out-patient PR program participated in this study. Patients grouped according to diffusion capacity as moderate or severe. Outcome measures were exercise capacity (6mWT), dyspnea sensation, pulmonary function tests, blood gases analysis, quality of life (QoL) and psychological symptoms.

RESULTS

A total of 68 patients enrolled in the study. Thirty-two (47%) of them had moderate diffusion defect [Tl_CO; 52 (47-61)mmol/kPa] and 36 (53%) of them had severe diffusion defect [Tl_CO; 29 (22-34)mmol/kPa]. At the end of the program, PaO₂ (p=0.001), Modified Medical Research Council dyspnea scale (p=0.001), 6mWT (p<0.001) and quality of life parameters improved significantly in both groups (p<0.05). Also the improvement in Dl_CO (p=0.04) value and FEV₁% (p=0.01) reached a statistically significant level in patients with severe diffusion defect. When comparing changes between groups, dyspnea reduced significantly in patients with severe diffusion defect (p=0.04).

CONCLUSION

Pulmonary rehabilitation improves oxygenation, severity of dyspnea, exercise capacity and quality of life independent of level of carbon monoxide diffusion capacity in patents with COPD. Furthermore pulmonary rehabilitation may improve Dl_CO values in COPD patients with severe diffusion defect.

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.

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

OBJECTIVES

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

DESIGN

Cross-sectional study.

SETTING

University teaching hospital.

PARTICIPANTS

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

OUTCOME MEASURES

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

RESULTS

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

CONCLUSION

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

A prospective randomized wait list control trial of intravenous iron sucrose in older adults with unexplained anemia and serum ferritin 20-200 ng/mL

Anemia is common in older persons and is associated with substantial morbidity and mortality. One third of anemic older adults have unexplained anemia of the elderly (UAE). We carried out a randomized, wait list control trial in outpatients with UAE and serum ferritin levels between 20 and 200 ng/mL. Intravenous iron sucrose was given as a 200-mg weekly dose for 5 weeks either immediately after enrollment (immediate intervention group) or following a 12-week wait list period (wait list control group). The primary outcome measure was changed in 6-minute walk test (6MWT) distances from baseline to 12 weeks between the two groups. Hematologic, physical, cognitive, and quality of life parameters were also assessed. The study was terminated early after 19 subjects enrolled. The distance walked in the 6MWT increased a mean 8.05±55.48 m in the immediate intervention group and decreased a mean 11.45±49.46 m in the wait list control group (p=0.443). The hemoglobin increased a mean 0.39±0.46 g/dL in the immediate intervention group and declined a mean 0.39±0.85 g/dL in the wait list control group (p=0.026). Thus, a subgroup of adults with UAE may respond to intravenous iron. Enrollment of subjects into this type of study remains challenging.

Tele-accelerometry as a novel technique for assessing functional status in patients with heart failure: feasibility, reliability and patient safety

BACKGROUND

The six-minute walk test (6MWT) is an established measure of functional exercise capacity associated with clinical prognosis in Chronic Heart Failure (CHF). The aim of this study is to evaluate the employment of tele-accelerometry for the remote assessment of 6MWT in CHF.

METHODS

155 patients were subjected to tele-accelerometry in form of monthly 6MWTs in their home surroundings. Accelerometer output included steps/6 min and walking speed. Data was directly transferred via mobile network to the Telemedicine Centre subsequent to test completion. 6MWT distance was measured by hand wheel and steps were counted with a digital hand-counter at baseline (Test 1) and at 12 months follow-up (Test 2).

RESULTS

Accelerometer accuracy was within the 99th percentile. There was a significant correlation between step count, walking speed and measured 6MWT distance (Test 1: steps: r=0.80, P<0.001; Test 2: steps: r=0.90, P<0.001 and Walking Speed Test 1: r=0.80, P<0.001; Walking Speed Test 2: r=0.86, P<0.001). The reproducibility of tele-accelerometry was within 95% margin for all performance parameters, which showed stronger associations to quality of life questionnaire (Short Form - 36) Physical Component Score (PCS) than New York Heart Association (NYHA) functional class.

CONCLUSION

Tele-accelerometry is feasible in patients with CHF and output parameters are indicative of exercise capacity. The benefit of this approach lies in its simplicity under every day circumstances by enabling routine performance testing to assess patients' functional status.