Six-minute walk test as clinical end point in cardiomyopathy clinical trials, including ATTR-CM: a systematic literature review.

Aim: The six-minute walk test (6MWT) is a common measure of functional capacity in patients with heart failure (HF). Primary clinical study end points in cardiomyopathy (CM) trials, including transthyretin-mediated amyloidosis with CM (ATTR-CM), are often limited to hospitalization and mortality. Objective: To investigate the relationship between the 6MWT and hospitalization or mortality in CM, including ATTR-CM. Method: A PRISMA-guided systematic literature review was conducted using search terms for CM, 6MWT, hospitalization and mortality. Results: Forty-one studies were identified that reported 6MWT data and hospitalization or mortality data for patients with CM. The data suggest that a greater 6MWT distance is associated with a reduced risk of hospitalization or mortality in CM. Conclusion: The 6MWT is an accepted alternative end point in CM trials, including ATTR-CM.

Prognostic Value of a 6-Minute Walk Test in Patients With Transthyretin Cardiac Amyloidosis.

BACKGROUND: The 6-minute walk test (6MWT) represents a comprehensive functional assessment that is commonly used in patients with heart failure; however, data are lacking in patients with transthyretin cardiac amyloidosis (ATTR-CA). OBJECTIVES: This study aimed to assess the prognostic importance of the 6MWT in patients with ATTR-CA. METHODS: A retrospective analysis of patients diagnosed with ATTR-CA at the National Amyloidosis Centre who underwent a baseline 6MWT between 2011 and 2023 identified 2,141 patients, of whom 1,118 had follow-up at 1 year. RESULTS: The median baseline 6MWT distance was 347 m (Q1-Q3: 250-428 m) and analysis by quartiles demonstrated an increased death rate with each distance reduction (deaths per 100 person-years: 6.3 vs 9.2 vs 13.6 vs 19.0; log-rank P < 0.001). A 6MWT distance of <350 m was associated with a 2.2-fold higher risk of mortality (HR: 2.15; 95% CI: 1.85-2.50; P < 0.001), with a similar increased risk across National Amyloidosis Centre disease stages (P for interaction = 0.761) and genotypes (P for interaction = 0.172). An absolute (reduction of >35 m) and relative worsening (reduction of >5%) of 6MWT at 1 year was associated with an increased risk of mortality (HR: 1.80; 95% CI: 1.51-2.15; P < 0.001 and HR: 1.89; 95% CI: 1.59-2.24; P < 0.001, respectively), which was similar across the aforementioned subgroups. When combined with established measures of disease progression (N-terminal pro-B-type natriuretic peptide progression and outpatient diuretic intensification), each incremental increase in progression markers was associated with an increased death rate (deaths per 100 person-years: 7.6 vs 13.9 vs 22.4 vs 32.9; log-rank P < 0.001). CONCLUSIONS: The baseline 6MWT distance can refine risk stratification beyond traditional prognosticators. A worsening 6MWT distance can stratify disease progression and, when combined with established markers, identifies patients at the highest risk of mortality.

Responsiveness and minimal clinically important difference of the 6-minute walk distance in patients undergoing colorectal cancer surgery.

PURPOSE: This study aimed to clarify the responsiveness and minimal clinically important difference (MCID) of the 6-minute walk distance (6MWD) from before and 1 week after surgery in patients with colorectal cancer (CRC). METHODS: This retrospective cohort study enrolled 97 patients with primary CRC scheduled for surgery. An anchor-based approach estimated the MCID of the 6MWD, with postoperative physical recovery and EuroQol 5-dimension 5L questionnaire assessments serving as anchors. Effect size (ES) and standardized response mean (SRM) of the 6MWD were calculated to evaluate responsiveness, and the receiver operating characteristic (ROC) curve was used to estimate the MCID of the 6MWD. RESULTS: Of the 97 patients, 72 were included in the analysis. The absolute value of ES and SRM of the 6MWD were 0.69 and 0.91, respectively. The ROC curve indicated that the optimal cut-off values for estimating the MCID of the 6MWD were -60 m (area under the curve [AUC] = 0.753 [95% CI: 0.640-0.866]) and -75 m (AUC = 0.870 [95% CI: 0.779-0.961]) at each anchor. CONCLUSION: From before to 1 week after surgery, the responsiveness of the 6MWD was favorable, and the MCID of the 6MWD was -75 to -60 m in patients with CRC.

Exercise capacity prior to major cancer surgery: A cross-sectional observational study of the validity of the 6-minute walk and 30-second sit-to-stand tests.

INTRODUCTION: Cardiopulmonary exercise testing (CPET) is the gold standard for measuring exercise capacity, however, it is resource intensive and has limited availability. This study aimed to determine: 1) the association between the 6-min walk test (6MWT) and the 30-s sit-to-stand test (30STS) with CPET peak oxygen uptake (VO2peak) and anaerobic threshold (AT) and 2) 6MWT and 30STS cut points associated with a higher risk of postoperative complications. METHODS: A cross-sectional study, retrospectively analyzing data collected from a tertiary cancer center over a 23-month period. Measures included CPET VO2peak and AT, 6MWT and 30STS test. Correlations were used to characterize relationships between variables. Receiver operating characteristic curve analyses determined 6MWT and 30STS cut points that aligned with CPET variable cut points. RESULTS: Note that, 156 participants were included. The 6MWT and 30STS displayed moderate correlations with VO2peak, rho = 0.65, p = 0.01 and rho = 0.52, p < 0.005 respectively. Fair correlations were observed between AT and 6MWT (rho = 0.36, p = 0.01) and 30STS (rho = 0.41, p < 0.005). The optimal cut points to identify VO2peak < 15 mL/kg/min were 493.5 m on the 6MWT and 12.5 stands on the 30STS test and for AT < 11 mL/kg/min were 506.5 m on the 6MWT and 12.5 stands on the 30STS test. CONCLUSION: Both the 6MWT and 30STS test could be used as alternative tools for measuring exercise capacity preoperatively in the cancer setting where CPET is not available. A range of 6MWT and 30STS cut points, according to sensitivity and specificity levels, may be used to evaluate risk of postoperative outcomes.

Usefulness of oxygen uptake efficiency slope in a 6 min walk test in chronic heart failure.

AIMS: Frailty is an obstacle to performing cardiopulmonary exercise test (CPET) in patients with chronic heart failure (CHF). We evaluated the usefulness of oxygen uptake efficiency slope (OUES) using a 6 min walk test (6MWT) with portable gas analysis compared with CPET-derived parameters in patients with CHF. METHODS AND RESULTS: Patients with CHF who underwent both the 6MWT with portable gas analysis and CPET between December 2016 and May 2020 were retrospectively investigated. The 6MWT-derived and echocardiographic parameters were compared with the OUES and peak oxygen consumption (VO2) from the CPET. Forty patients were analysed; 50% were male with a mean age of 55.45 ± 14.70 years. Twenty-six patients (65%) had New York Heart Association Functional Classification II or III dyspnoea. Twenty-five patients (62.5%) had heart failure (HF) with preserved ejection fraction (EF) (left ventricular EF > 50%), and nine patients (22.5%) had HF with reduced EF (EF < 40%). During the 6MWT, the peak VO2 was 14.97 ± 3.80 mL/kg/min, which was only 74% of the peak VO2 in the CPET, 20.18 ± 5.64 mL/kg/min. The OUES in the 6MWT was lower than that in the CPET (1528.87 ± 579.01 in the 6MWT vs. 1638.69 ± 601.31 in the CPET). The 6 min walk distance (6MWD) and OUES in the 6MWT were positively correlated with the OUES in the CPET (6MWD, r = 0.434, P = 0.005; OUES, r = 0.729, P < 0.001). The OUES in the 6MWT showed the strongest correlation with the OUES in the CPET. When we divided patients into two groups according to peak VO2 in the CPET, the correlation between OUES values of the 6MWT and that of the CPET was consistently confirmed (peak VO2 ≥ 20 mL/kg/min group, r = 0.661, P = 0.001; peak VO2 < 20 mL/kg/min group, r = 0.526, P = 0.021). In addition, the 6MWD, OUES, and peak VO2 in the 6MWT were associated with peak VO2 in the CPET (6MWD, r = 0.627, P < 0.001; OUES, r = 0.452, P = 0.003; and peak VO2, r = 0.492, P = 0.001). CONCLUSIONS: In frail patients with CHF who have difficulty performing maximal exercises, the OUES through the 6MWT may be applied instead of the OUES and peak VO2 from the CPET.

Hemodynamic, ventilatory and gas exchange responses to exercise using a cycle ergometer and the incremental shuttle walk test in pregnant women.

BACKGROUND: Cardiovascular disease, including hypertension, in pregnant women is a leading cause of morbidity and mortality globally. The development of reference intervals for cardiovascular responses using exercising testing to measure oxygen utilisation (V̇O2) with cardiopulmonary exercise testing (CPET), and distances walked using the incremental shuttle walk test (ISWT), may be promising methods to assess and stratify pregnant women regarding their risk of adverse pregnancy outcomes, to encourage exercise during pregnancy, and to improve exercise prescriptions during pregnancy. We aimed to determine the reference intervals for V̇O2 at rest, anaerobic threshold (AT), and submaximal exercise using CPET, and the reference interval for the ISWT, to develop a correlation equitation that predicts submaximal V̇O2 from the distance walked in the ISWT, and to explore the relationship between hemoglobin (Hb) and ferritin concentration and V̇O2 at AT in women in second trimester. METHODS: After prospective IRB approval (HREC 15/23) and clinical trials registration (ANZCTR ACTRN12615000964516), and informed written consent, we conducted CPET and the ISWT according to international guidelines in a university associated tertiary referral obstetric and adult medicine hospital, in healthy pregnant women in second trimester (14 to 27 gestational weeks). Hemoglobin and ferritin concentrations were recorded from pathology results in the participants' medical records at the time of exercise testing. Adverse events were recorded. RESULTS: About 90 participants undertook CPET, 28 of which also completed the ISWT. The mean ± SD age and body mass index (BMI) were 32 ± 3.2 years, and 25 ± 2.7 kg/m2. Median (IQR) gestation was 23 (22-24) weeks. One in 4 women were 24 weeks or greater gestation. The reference intervals for V̇O2 at rest, AT, and submaximal exercise were 2.9 to 5.3, 8.1 to 20.7, and 14.1 to 30.5 mL/kg/min respectively. The reference interval for the ISWT was 218 to 1058 meters. The correlation equation to predict submaximal V̇O2 from the distance walked in the ISWT was submaximal V̇O2 (mL/kg/min) = 0.012*distance walked in ISWT (m) + 14.7 (95%CI slope 0.005-0.070, Pearson r = 0.5426 95%CI 0.2126-0.7615, P = .0029). Hemoglobin concentration was positively correlated with V̇O2 at AT (AT V̇O2 (mL/kg/min) = 0.08*Hb (g/L) + 4.9 (95%CI slope 0.0791-0.143, Pearson r = 0.2538 95%CI 0.049-0.438, P = .016). There was no linear association between ferritin and submaximal V̇O2 (Pearson r = 0.431 P = .697). There were no maternal or fetal complications. CONCLUSIONS: CPET and ISWT are safe and feasible in women in second trimester including those at or beyond 24 weeks gestation. We have established the reference interval for V̇O2 at rest, AT, and submaximal exercise by CPET, the reference interval for the distance walked for the ISWT, and a correlation equation to predict submaximal V̇O2 for use in clinical practice and research. Hemoglobin rather than ferritin is likely correlated with exercise capacity in pregnancy suggesting vigilance to correct lower hemoglobin levels may positively impact maternal health. CLINICAL TRIALS REGISTRY: The study was prospectively registered with the Australian and New Zealand Clinical Date of registration - 15/9/2015; Date of initial participant enrolment - 4/11/2015; Clinical trial identification number; ACTRN12615000964516; URL of the registration site - https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=369216.

Preoperative 6-minute walk distance is associated with postoperative complications in patients undergoing laparoscopic gastrointestinal cancer surgery.

OBJECTIVE: The 6-min walk test (6MWT) is a simple and valid method to evaluate cardiopulmonary function. We performed this prospective study in patients undergoing laparoscopic gastrointestinal cancer surgery to explore the association between preoperative 6MWT performance and overall postoperative complications. METHODS: This study was registered at clinicaltrials.gov (NCT03711526). The study consecutively enrolled patients receiving laparoscopic gastrointestinal cancer surgery in our institution. All patients performed the 6MWT upon recruitment and received 30 days of postoperative follow-up. The primary outcome was overall complications, defined by ≥ grade I Clavien-Dindo (CD) classification (2004) complications. Multivariable logistic regression was used to test the association of 6-min walk distance (6MWD) with the outcome. RESULTS: A total of 184 patients were included in the final analyses. In the 37 (20.1 %) patients with overall complications, the mean (standard deviation) preoperative 6MWD was 469.1 (86.8) m. In patients with no complications, the 6MWD was 502.6 (90.2) m. The mean difference was 33.5 m (95 % confidence interval, 1.3, 65.7; P = 0.042). A longer preoperative 6MWD was associated with a lower odds of developing postoperative complications (odds ratio, 0.994 per meter increase; 95 % confidence interval, 0.989, 0.999; p = 0.023). CONCLUSION: This study indicated an association between the preoperative 6MWD and postoperative complications in patients undergoing laparoscopic gastrointestinal cancer surgery.

Pulmonary function test results are correlated with 6-minute walk distance, distance-saturation product, and 6-minute walk work in patients with lymphangioleiomyomatosis.

BACKGROUND AND OBJECTIVE: Lymphangioleiomyomatosis (LAM) is a rare multicystic lung disease. Although a correlation between pulmonary function test (PFT) results and exercise capacity appears probable, it has not yet been demonstrated. The aim of this study was to assess whether PFT results correlate with 6-minute walk test (6MWT) results in patients with LAM. METHODS: We conducted a retrospective study of all patients with a diagnosis of LAM followed in a French reference centre over a 13-year period. PFT and 6MWT data were collected. Distance-saturation product (DSP) and 6-minute walk work (6MWORK) were calculated. RESULTS: A total of 62 patients were included. Their median forced expiratory volume in 1 s (FEV1) was 82.7 % predicted and their median forced vital capacity (FVC) was 96.7 % predicted. The median diffusing capacity of the lungs for carbon monoxide (DLCO) was 58.5 % predicted and was decreased in 79 % of the patients. The median 6-minute walk distance was 535 m, which was 90.9 % of the 602 m predicted distance. The median DSP was 497.4 m % and the median 6MWORK was 32,910 kg.m. The distance walked during the 6MWT was significantly correlated with FVC%predicted (R = 0.435), FEV1 %predicted (R = 0.303), TLC%predicted (R = 0.345), FRC%predicted (R = 0.262), RV/TLC ratio (R = -0.271), and DLCO%predicted (R = 0.279). DSP and 6MWORK were each significantly correlated with different PFT results. CONCLUSION: The present study shows that PFT results are potential predictors of the exercise capacity in patients with LAM. Additional studies are required to evaluate the interest of DSP and 6MWORK in LAM.

Relación entre la distancia recorrida en la prueba de caminata de 6 minutos y el sexo, la edad, comorbilidades y la disnea en pacientes con EPOC / Relationship between the Distance Traveled in the Test of 6- Minute Walk and Sex, Age, Comorbidities and Dyspnea in Patients with CORP

Introducción: la enfermedad pulmonar obstructiva crónica (EPOC) es un trastorno res-piratorio caracterizado por síntomas clínicos y compromiso funcional que afecta la ca-pacidad aeróbica limitando las actividades cotidianas y la calidad de vida. La prueba de caminata de 6 minutos (C6M) es una prueba sencilla y de bajo costo que evalúa la capa-cidad de los pacientes para realizar sus actividades cotidianas. Objetivo: evaluar la re-lación entre la capacidad aeróbica medida por la distancia recorrida en la C6M y el se-xo, edad, disnea y comorbilidades cardiometabólicas en pacientes con EPOC. Material y métodos: estudio de corte transversal, descriptivo, basado en pruebas de caminatas de 6 minutos (C6M) realizadas en pacientes con EPOC. Resultados: se evaluaron 101 pacientes, hombres (63,4%), con una edad promedio de 74,1±8,7 años. Al correlacionar C6M con otras variables se encontraron diferencias estadísticamente significativas. La distancia media recorrida fue mayor en hombres que en mujeres (DM: 58,3 metros, IC 95%; 16 - 100,6, p=0,007). Los pacientes < 75 años, sin comorbilidades y disnea < 2 tu-vieron mejor desempeño en la C6M que los > 75 años (DM; 62,012 metros IC 95% 21,5 - 102,4, p=0,003), con comorbilidades (DM: 42,2 metros, IC 95%, 0.003 - 84,4; p=0,050) y disnea ≥ 2 (DM: 65,8 IC 95% 23,9 - 107,6, p=0,002). Conclusiones: el sexo femenino, la presencia de comorbilidad cardiovascular y metabólica, y la edad se asocian con dis-minución en la capacidad física aeróbica y funcional en los pacientes con EPOC. (AU)

Introduction: chronic obstructive pulmonary disease (COPD) is a respiratory disorder characterized by clinical symptoms and functional impairment that affects aerobic capacity, limiting daily activities and quality of life. The 6-minute walk test (C6M) is a simple, low-cost test that assesses a patient's ability to perform their daily activities. Objective: to evaluate the relationship between aerobic capacity measured by the distance covered in the C6M and gender, age, dyspnea and cardiometabolic comorbidities in patients with COPD. Materials and methods: cross-sectional, descriptive study, based on 6-minute walk tests (C6M) performed in patients with COPD. Results: 101 male patients (63.4%), with a mean age of 74.1 ± 8.7 years, were evaluated. When correlating C6M with other variables, statistically significant differences were found. The mean distance traveled was greater in men than in women (MD: 58.3 meters, 95% CI: 16 - 100.6, p=0.007). Patients <75 years old, without comorbidities and dyspnea <2 had better performance in the C6M than those >75 years old (MD; 62 meters CI 95% 21.5 - 102.4, p=0.003), with comorbidities (MD: 42.2 meters, 95% CI, 0.003 - 84.4; p=0.050) and dyspnea ≥ 2 (MD: 65.8, 95% CI 23.9 - 107.6, p=0.002). Conclusions: female sex, the presence of cardiovascular and metabolic comorbidity, and age are associated with decreased aerobic and functional physical capacity in patients with COPD. (AU)

Validity of the 30-Second Chair-Stand Test to Assess Exercise Tolerance and Clinical Outcomes in Patients with Esophageal Cancer: A Retrospective Study with Reference to 6-Minute Walk Test Results.

This retrospective study aimed to investigate the validity of a 30-sec chair stand test (CS-30) as a simple test to assess exercise tolerance and clinical outcomes in 53 Japanese patients with esophageal cancer. There was a strong correlation between the results of CS-30 and the 6-min walk test (6MWT), the gold standard for assessing exercise tolerance (r=0.759). Furthermore, fewer patients whose CS-30 score was greater than 16 (the cutoff value defined based on 6MWT) experienced pneumonia in their postoperative course. These results suggest that exercise tolerance could be assessed using CS-30, and its cutoff value may be useful in predicting postoperative pneumonia risk.

The 2 min step test: A reliable and valid measure of functional capacity in older adults post coronary revascularisation.

PURPOSE: Exercise training is the central component in Cardiac Rehabilitation (CR). A baseline assessment of aerobic capacity is paramount for exercise prescription and safety. The Two-Minute Step Test (2MST) has been used to measure aerobic capacity in healthy older adults. However, the reliability and validity of the 2MST in older adults post-coronary revascularisation (CRV) is unknown. METHODS: A prospective observational study was conducted in a single CR centre. Two 2MSTs and one six-minute walk test (6MWT) were completed in a single session. The 2MST measurements were recorded by two raters for each individual. The six-minute walk distance (6MWD) and 2MST steps recorded by both raters were analysed to determine the relationship and agreement between measurements. RESULTS: Thirty one participants with a median (IQR) age of 66 (62,73) years old were included in the study post CRV. Strong positive correlations were found between steps achieved during the 2MSTs and the 6MWD (r = 0.87, 95% CI 0.82-0.91, p < 0.0001). Excellent inter-rater reliability was demonstrated between raters during the 2MSTs (ICC = 0.999-1.000, p = 0.000). Excellent relative test-retest reliability was demonstrated in both 2MSTs recorded by both raters (ICC = 0.927-0.934, p = 0.000). However, absolute test-retest reliability may have been limited by a learning effect between repeated 2MSTs. CONCLUSIONS: The results of this study indicate that the 2MST may be used as an alternative to the 6MWT as an outcome measure for aerobic capacity in older adults post-CRV. However, a practice trial is recommended at baseline to account for a learning effect.

Body functions and structure, activity, and participation limitations of adult cystic fibrosis patients under the international classification of functioning, disability, and health framework.

Objective: There is no study in the literature evaluating impairments and functional limitations in adults with cystic fibrosis (CF) under the framework of the International Classification of Functioning, Disability, and Health (ICF). To evaluate the adults with CF using ICF model. Methods: Twenty-three adults with CF and 23 age-sex matched healthy individuals included in this cross-sectional study. The participants evaluated according to the selected items for domain b, domain s, and domain d from the Obstructive Pulmonary Diseases (OPD) Comprehensive Core Set. The body composition, pulmonary functions, respiratory and peripheral muscle strength/endurance tests and anxiety/depression level were evaluated for domain b and s. For domain d, the Incremental Shuttle Walk Test (ISWT) and Short Form-36 (SF-36) Health Survey were used. Results: The fat-free mass (p = .044), pulmonary functions (p < .05), respiratory muscle endurance (p = .010), absolute and %quadriceps muscle strength (p = .001, p = .025, respectively), number of sit-ups (p = .020), walking speed (p = .035), ISWT and ISWT% distance (p < .001) and peak oxygen consumption (p < .001) were significantly lower in adults with CF compared to healthy individuals (p < .05). There were only significant differences in SF-36 physical functioning and role physical subdimension scores between groups (p = .009, p = .045 respectively). Conclusions: The ICF framework is applicable to comprehensively evaluate limitations of adults with CF among rehabilitation professionals. Especially age, respiratory function, respiratory muscle strength and endurance, dyspnea perception, peripheral muscle endurance were related to activity and participation limitation.

Clinically Meaningful Change in 6 Minute Walking Test and the Incremental Shuttle Walking Test following Coronary Artery Bypass Graft Surgery.

The 6-min walk test (6MWT) and incremental shuttle walk test (ISWT) are widely used measures of exercise tolerance, which depict favorable performance characteristics in a variety of cardiac and pulmonary conditions. Both tests are valid and reliable method of assessing functional ability in cardiac rehabilitation population. Several studies have calculated the minimal clinically important difference (MCID) of these exercise tests in different populations. The current study aims to estimate MCID of 6MWT and ISWT in patients after Coronary artery bypass graft (CABG) surgery. In this descriptive observational study, nonprobability purposive sampling technique was used to assess 89 post CABG patients. The participants performed the 6MWT and ISWT along with vital monitoring on third, fifth and seventh post operative days. The data was with calculation of 6MWT and ISWT MCID through distribution and anchor-based methods. Results showed significant improvement (p < 0.001) in 6MWT as well as in ISWT after seven days of in-patient cardiac rehabilitation. The minimal detectable difference of 6MWT determined by the distribution-based method was 36.11 whereas MCID calculated by Anchor based method was 195 m. The minimal detectable difference of ISWT determined by the distribution-based method was 9.94 whereas MCID calculated by Anchor based method was 42.5 m. In conclusion our results will assist the future researchers and clinicians to interpret clinical trials as well as to observe the clinical course of post operative cardiac patients.

Exercise Self-Efficacy and patient global assessment were associated with 6-min walk test distance in persons with rheumatoid arthritis.

INTRODUCTION: Low functional capacity is related to future loss of daily function and cardiovascular events. The present study explored the associations of patient-reported outcome measures (PROMs) and disease-specific measures with functional capacity as measured by the 6-min walk test (6MWT) in persons with rheumatoid arthritis (RA). METHODS: Seventy-nine participants from rheumatology outpatient clinics were included. The distance walked during the 6MWT (6MWD) was the dependent variable in multivariable regression analyses. Model 1 included the independent variables sex, age (in tertiles to improve model fit), and body mass index (BMI). Building on Model 1, Model 2 added smoking, patient global assessment (PGA), Exercise Self-Efficacy, Hospital Anxiety and Depression Scale's Depression score, and Cohen's Perceived Stress Scale score, whereas Model 3 added smoking, disease duration, present use of glucocorticosteroids, seropositivity, Disease Activity Score 28-C-Reactive Protein (DAS28-CRP), and a comorbidity variable. RESULTS: Median age was 65 years, 76% were female, and median 6MWD was 493 m. In Model 1, BMI and age were significantly associated with the 6MWD (R2 = 0.42). In Model 2, PGA and Exercise Self-Efficacy were also significantly associated with the 6MWD, with standardized regression coefficients of - 0.21 (p = 0.03) and 0.26 (p = 0.004) respectively (R2 = 0.54). The RA-specific variables in Model 3 were not significantly associated with the 6MWD (R2 = 0.49). CONCLUSION: The PROMs PGA and Exercise Self-Efficacy were significantly associated with functional capacity as measured by the 6MWT in persons with RA, whereas disease-specific measures such as DAS28-CRP and disease duration were not. Key Points • Functional capacity measured with the 6-minute walk test was significantly associated with body mass index, age, patient global assessment, and Exercise Self-Efficacy in persons with RA. • Patient-reported outcome measures explained more of the variation in functional capacity than objective or composite measures of disease and are relevant measures in clinical follow-up. • Techniques that enhance self-efficacy for exercise should be incorporated into clinical practice to promote physical activity.

Cardiorenal syndrome and the association with fitness: Data from a telerehabilitation randomized clinical trial.

AIMS: To investigate the associations of cardiorespiratory fitness with cardiac, vascular, renal and cardiorenal characteristics in chronic heart failure in a telerehabilitation randomized clinical trial. Secondly, to evaluate the associations of cardiorenal syndrome with the effects of exercise. METHODS AND RESULTS: Sixty-nine heart failure patients attended baseline examination, and 61 patients were randomly assigned 1:1 to 3-month telerehabilitation or control. Data were collected at baseline and 3-month post-intervention, including echocardiography and vascular ultrasound, laboratory tests, exercise test with peak oxygen consumption (VO2peak ) measurement and 6-min walk test (6MWT). Baseline VO2peak and 6MWT distance was 0.85 mL*min-1 *kg-1 lower and 20 m shorter per 10 mL/min/1.73m2 lower estimated glomerular filtration rate (both P < 0.001). Heart failure patients with cardiorenal syndrome had 3.5 (1.1) mL*min-1 *kg-1 lower VO2peak and diastolic dysfunction grade 2-3, and elevated filling pressure was >50% more common compared with those without (all P < 0.05). At the 3-month post-intervention follow-up, only the non-CRS patients in the intervention group increased VO2peak (0.73 (0.51) mL*min-1 *kg-1 ), whereas VO2peak in the CRS subpopulation of controls decreased (-1.34 (0.43) mL*min-1 *kg-1 ). Cardiorenal syndrome was associated with a decrease in VO2peak in CRS patients compared with non-CRS patients, -0.91 (0.31) vs. 0.39 (0.35) mL*min-1 *kg-1 respectively, P = 0.013. CONCLUSIONS: Cardiorenal syndrome was negatively associated with VO2peak and 6MWT distance in chronic HF, and the associations were stronger than for heart failure phenotypes and other characteristics. The effect of exercise was negatively associated with cardiorenal syndrome. Exercise seems to be as important in heart failure patients with cardiorenal syndrome, and future studies should include CRS patients to reveal the most beneficial type of exercise.

Predicting recovery and disability after surgery in patients with severe obesity: The role of the six-minute walk test.

The most appropriate method to predict postoperative outcomes in patients with severe obesity undergoing elective non-bariatric surgery is not known. We conducted a single-centre prospective cohort study in patients with a body mass index of at least 35 kg/m2 undergoing non-bariatric, non-cardiac surgery. Patients completed the six-minute walk test prior to surgery. Disability was measured before and six months after surgery using the World Health Organization disability assessment schedule. Primary outcome measures included quality of recovery at one month and significantly increased disability at six months after surgery. A total of 293 patients participated. The median body mass index was 41 kg/m2. Patients generally recovered well. Following surgery, 9% of patients experienced a poor quality of recovery and 7% developed a significant increase in disability. The proportion of patients free from clinically significant disability increased from 66% prior to surgery to 90% at six months after surgery. The distance walked in six minutes was weakly predictive of poor recovery at one month and significantly increased disability at six months; weight and body mass index were not. The area under the receiver operating characteristic curve was 0.65 (95% confidence intervals 0.51 to 0.78) for poor recovery and 0.64 (95% confidence intervals 0.51 to 0.77) for increased disability. A preoperative six-minute walk test distance of 308 m was the best cut-off value for predicting increased postoperative disability (sensitivity 0.68, specificity 0.63). The six-minute walk test was most discriminatory at shorter distances. This population of patients with severe obesity appeared to recover well and had few adverse outcomes. The degree of functional capacity was more important than the degree of obesity in predicting postoperative outcomes.

Relationship of subjective and objective sleep measures with physical performance in advanced-stage lung cancer patients.

Advanced lung cancer patients suffer from deteriorated physical function, which negatively impacts physical and psychological health. As little is known about sleep and physical function in this population, this study aimed to examine the association between subjective and objective sleep parameters and physical function among them. 164 advanced lung cancer patients were included. Objective sleep was measured by actigraphy (measured on non-dominant wrist for 72 h), and subjective sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI). Performance-based physical function was measured by Timed Up and Go Test (TUGT), 6-Minute Walk Test (6MWT), Sit-to-Stand Test, and One-leg Standing Test. Univariable and multivariable regression analyses were employed to examine the association between sleep and physical function. Total sleep time (TST) was significantly associated with the 6MWT (ß = 0.259; 95% CI 0.120, 0.398; P < 0.001), TUGT (ß = - 0.012; 95% CI = - 0.017, - 0.008; P < 0.001) and Sit-to-Stand Test (ß = 0.027; 95% CI = 0.018, 0.035; P < 0.001) after adjustment for multiple covariates. PSQI global score was only significantly associated with TUGT (ß = 0.140; 95% CI = 0.000, 0.280; P = 0.050) after adjustment for multiple covariates. Shorter sleep duration significantly predicted poorer physical performance in advanced lung cancer patients, and more attention is required for those with less than 4.3 h of sleep on average.Trial registration: ClinicalTrials.gov, NCT03482323. Registered 29 March 2018, https://clinicaltrials.gov/ct2/show/NCT03482323 ; ClinicalTrials.gov, NCT04119778. Registered 8 October 2019, https://clinicaltrials.gov/ct2/show/NCT04119778 .

Reference Equation for the Six-Minute Walk Test in Brazilian Patients with Obesity

Abstract Background: Obesity has repercussions on functional capacity (FC). The six-minute walk test (6MWT) is a useful tool for assessing submaximal FC, and the distance reached at 6 minutes of walking (D6MW) is a relevant prognostic marker. Objective: This paper aims to establish a reference equation for the distance predicted in 6MWT in obese Brazilian subjects. Methods: This study included 460 patients (306 women), with a body mass index (BMI) > 30 kg/m2, 71% (328) of whom presented a grade III obesity (BMI ≥ 40 Kg/m²) and were evaluated with 6MWT. Heart rate, blood pressure, oxygen saturation and Borg scale perception of effort were recorded before and after the 6MWT. For statistical analysis, Kolmogorov-Smirnov tests, an unpaired T-Test, Pearson's correlation, and multiple linear regression were used, together with a significance level set at p<0.05. Results: Gender, age, and BMI were significantly correlated with D6MW and were identified by multiple linear regression as the best predictors of the D6MW. Together, they explain 48.7% of the D6MW variance for obese Brazilian subjects. Based on these findings, an equation was proposed - D6MW = 930.138 + (27.130 x Genderfemales = 0; males = 1) − (5.550 x BMI kg/m2) − (4.442 x Age years). When the average of the D6MW obtained with the above equation was compared to the average calculated with the equations described in medical literature for healthy and obese individuals, the latter tended to overestimate the D6MW. Conclusion: The proposed reference equation exhibited better assessment of FC in obese Brazilian patients, providing proper subsidies for the follow up ofinterventions in this population..

A role for cardiopulmonary exercise testing in detecting physiological changes underlying health status in Idiopathic pulmonary fibrosis: a feasibility study.

INTRODUCTION: There is limited data available on the use of CPET as a predictive tool for disease outcomes in the setting of IPF. We investigated the feasibility of undertaking CPET and the relationship between CPET and quality of life measurements in a well-defined population of mild and moderate IPF patients. METHODS: A prospective, single-centre observational study. RESULTS: Thirty-two IPF patients (mild n = 23, moderate n = 9) participated in the study, n = 13 mild patients attended for repeat CPET testing at 12 months. At baseline, total K-BILD scores and total IPF-PROM scores significantly correlated with 6MWT distance, but not with baseline FVC % predicted, TLco % predicted, baseline or minimum SpO2. VO2 peak/kg at AT positively correlated with total scores, breathlessness/activity and chest domains of the K-BILD questionnaire (p < 0.05). VO2 peak significantly correlated with total IPF PROM scores and wellbeing domains (p < 0.05), with a trend towards statistical significance for total IPF-PROM and VO2 peak/kg at anaerobic threshold (p = 0.06). There was a statistically significant reduction in FVC% predicted at 12 months follow up, although the mean absolute decline was < 10% (p < 0.05). During this period VO2 peak significantly reduced (21.6 ml/kg/min ± 2.9 vs 19.1 ± 2.8; p = 0.017), with corresponding reductions in total K-BILD and breathlessness/activity domains that exceeded the MCID for responsiveness. Lower baseline VO2 peak/kg at anaerobic threshold correlated with greater declines in total K-BILD scores (r = - 0.62, 0.024) at 12 months. Whilst baseline FVC% predicted or TLco % predicted did not predict change in health status, CONCLUSION: We have shown that it is feasible to undertake CPET in patients with mild to moderate IPF. CPET measures of VO2 peak correlated with both baseline and change in K-BILD measurements at 1 year, despite relatively stable standard lung function (declines of < 10% in FVC), suggesting its potential sensitivity to detect physiological changes underlying health status.

Incidence and Prognostic Significance of Hypoxemia in Fibrotic Interstitial Lung Disease: An International Cohort Study.

BACKGROUND: Hypoxemia is a cardinal feature of fibrotic interstitial lung disease (ILD). The incidence, progression, and prognostic significance of hypoxemia in patients with fibrotic ILD currently is unknown. RESEARCH QUESTION: What are the epidemiologic features of hypoxemia and its additive prognostic value in a current risk prediction model of fibrotic ILD? METHODS: We identified 848 patients with fibrotic ILD (258 with idiopathic pulmonary fibrosis [IPF]) in five prospective ILD registries from Australia, Canada, and Switzerland. Cumulative incidence of exertional and resting hypoxemia from the time of diagnosis was estimated at 1-year intervals in patients with baseline 6-min walk tests, adjusted for competing risks of death and lung transplantation. Likelihood ratio tests were used to determine the prognostic significance of exertional and resting hypoxemia for 1-year mortality or transplantation when added to the ILD-GAP model. The cohort was divided into derivation and validation subsets to evaluate performance characteristics of the extended model (the ILD-GAP-O2 model), which included oxygenation status as a predictor. RESULTS: The 1-, 2-, and 5-year overall cumulative incidence was 6.1%, 17.3%, and 40.1%, respectively, for exertional hypoxemia and 2.4%, 5.6%, and 16.5%, respectively, for resting hypoxemia, which were significantly higher in patients with IPF compared with patients without IPF (P < .001 for both). Addition of exertional or resting hypoxemia to the ILD-GAP model improved 1-year mortality and transplantation prediction (P < .001 for both). The ILD-GAP-O2 model showed improved discrimination (C-index, 0.80 vs 0.75) and model fit (Akaike information criteria, 400 vs 422) in the validation cohort, with comparable calibration. INTERPRETATION: Patients with IPF have higher cumulative incidence of exertional and resting hypoxemia than patients without IPF. The extended ILD-GAP-O2 model provides additional risk stratification for 1-year prognosis in fibrotic ILD.