Reliability, validity, and responsiveness of the six-minute walk test in patients with heart failure. Six-Minute Walk Test and Cardiopulmonary Exercise Testing in Patients With Chronic Heart Failure: A Comparative Analysis on Clinical and Prognostic Insights Which field walking test should be used to assess functional exercise capacity in lung cancer? an observational study Randomized trial of Nordic walking in patients with moderate to severe heart failure. Relation of Longitudinal Changes in Quality of Life Assessments to Changes in Functional Capacity in Patients With Heart Failure With and Without Anemia. Six-minute-walk test in idiopathic pulmonary fibrosis: test validation and minimal clinically important difference. Daily walking performance as an independent predictor of advanced heart failure: Prediction of exercise capacity in chronic heart failure. Regression equations to predict 6-minute walk distance in middle-aged and elderly adults [Reference Equations for the 6-Minute Walk Test in Healthy Individuals.]
BACKGROUND Our purpose was to evaluate the reliability , validity , and responsiveness of the 6-minute walk test ( 6MWT ) in patients with heart failure ( HF ) enrolled in the R and omized Evaluation of Strategies for Left Ventricular Dysfunction ( RESOLVD ) pilot study . METHODS A total of 768 patients was enrolled in a multicenter r and omized clinical trial evaluating the effect of c and esartan , enalapril , and metoprolol on left ventricular ejection fraction ( LVEF ) , 6MWT distance , neurohormones , and quality of life . The 6MWT was performed once at screening and twice at baseline , 18 weeks , and 43 weeks by a st and ardized method . RESULTS Test-retest reliability at baseline ( intraclass correlation coefficient [ ICC ] = 0.90 ) , 18 weeks ( ICC = 0.88 ) , and 43 weeks ( ICC = 0.91 ) was very good . Baseline 6MWT distance was weakly inversely correlated to the quality -of-life cumulative score ( r = -0.26 , P = .0001 ) and moderately inversely correlated to the New York Heart Association functional classification ( NYHA-FC ) ( r = -0.43 , P = .001 ) . In the RESOLVD study , the 6MWT was not responsive to change when effect sizes and st and ardized response means were used . Disease-specific quality of life was responsive to change in patients treated with c and esartan and enalapril and NYHA-FC was responsive to change in the c and esartan and enalapril combination and for enalapril alone with small effect sizes . The 6MWT , NYHA-FC , and quality of life were not responsive to change during the metoprolol or placebo phase . CONCLUSIONS The 6MWT is highly reproducible in patients with symptoms of HF . It is somewhat correlated to NYHA-FC and quality of life . Overall , quality of life was most responsive to change , whereas 6MWT and NYHA-FC were comparable but less responsive to change in the RESOLVD study Background —The six-minute walk test ( 6MWT ) and cardiopulmonary exercise testing ( CPET ) are the 2 testing modalities most broadly used for assessing functional limitation in patients with heart failure ( HF ) . A comprehensive comparison on clinical and prognostic validity of the 2 techniques has not been performed and is the aim of the present investigation . Methods and Results —Two hundred fifty-three patients diagnosed with systolic ( n=211 ) or diastolic ( n=42 ) HF ( age : 61.9±10.1 years ; New York Heart Association Class : 2.2±0.78 ) underwent a 6MWT and a symptom-limited CPET evaluation and were prospect ively followed up . During the 4-year tracking period , there were 43 cardiac-related deaths with an annual cardiac mortality rate of 8.7 % . The 6MWT distance correlated with CPET-derived variables ( ie , peak Vo2 , Vo2 at anaerobic threshold , and Ve/Vco2 slope ) and was significantly reduced in proportion with lower peak Vo2 and higher Ve/Vco2 slope classes and presence of an exercise oscillatory breathing ( EOB ) pattern ( P<0.01 ) . However , no significant differences were observed in distance covered between survivors and nonsurvivors ( 353.2±95.8 m versus 338.5±76.4 m ; P = NS ) . At univariate and multivariate Cox proportional analyses , the association of the 6MWT distance with survival was not significant either as a continuous or dicotomized variable ( ≤300 m ) . Conversely , CPET-derived variables emerged as prognostic with the strongest association found for EOB ( systolic HF ) and Ve/Vco2 slope ( entire population with HF and patients with a 6MWT≤300 m ) . Conclusions —The 6MWT is confirmed to be a simple and reliable first-line test for quantification of exercise intolerance in patients with HF . However , there is no supportive evidence for its use as a prognostic marker in alternative to or in conjunction with CPET-derived variables Background There is emerging evidence regarding the efficacy of exercise training to improve exercise capacity for individuals with non-small cell lung cancer ( NSCLC ) .  Cardiopulmonary exercise testing ( CPET ) is the gold st and ard measure of exercise capacity ; however this laboratory test has limitations for use in research and clinical practice . Alternative field walking tests are the six-minute walk test ( 6MWT ) , incremental-shuttle walk test ( ISWT ) and endurance-shuttle walk test ( ESWT ) ; however there is limited information about their clinimetric properties in NSCLC . Aims : In NSCLC to determine the 1 ) criterion validity of the 6MWT , ISWT and ESWT against CPET ; 2 ) construct validity of the 6MWT , ISWT and ESWT against measures of function , strength , respiratory function and health-related quality of life ( HRQoL ) ; and 3 ) clinical applicability of the tests . Methods Twenty participants ( 40 % male , mean ± SD age 66.1 ± 6.5 years ) with stage I-IIIb NSCLC completed the 6MWT , ISWT , ESWT and CPET within six months of treatment . Testing order was r and omised . Additional measures included Eastern Cooperative Oncology Group Performance-Status ( ECOG-PS , function ) , respiratory function , h and -grip dynamometry and HRQoL. Correlations and regression analyses were used to assess relationships . Results The ISWT demonstrated criterion validity with a moderate relationship between ISWT distance and CPET peak oxygen consumption ( r = 0.61 , p = 0.007 ) . Relationships between CPET and six minute walk distance ( 6MWD ) ( r = 0.24 , p = 0.329 ) or ESWT time ( r = 0.02 , p = 0.942 ) were poor . Moderate construct validity existed for the 6MWD and respiratory function ( forced vital capacity % predicted r = 0.53 , p = 0.019 ; forced expiratory volume in the first second % predicted r = 0.55 , p = 0.015 ) . There were no relationships between the walking tests and measures of function , strength or HRQoL. The ESWT had a ceiling effect with 18 % reaching maximum time . No floor effects were seen in the tests . The mean ± SD time required to perform the individual 6MWT , ISWT and ESWT was 12.8 ± 2.5 , 14.7 ± 3.7 and 16.3 ± 5.0 min respectively ; in comparison to CPET which was 51.2 ± 12.7 min . Only one assessor was required to perform all field walking tests and no adverse events occurred . Conclusions The ISWT is a promising measure of functional exercise capacity in lung cancer . Findings need to be confirmed in a larger sample prior to translation into practice BACKGROUND Patients with heart failure are a growing population within cardiac rehabilitation . The purpose of this study was to compare , through a single-centre , parallel-group , r and omized controlled trial , the effects of Nordic walking and st and ard cardiac rehabilitation care on functional capacity and other outcomes in patients with moderate to severe heart failure . METHODS Between 2008 and 2009 , 54 patients ( aged 62.4 ± 11.4 years ) with heart failure ( mean ejection fraction = 26.9 % ± 5.0 % ) were r and omly assigned to st and ard cardiac rehabilitation care ( n = 27 ) or Nordic walking ( n = 27 ) ; both groups performed 200 to 400 minutes of exercise per week for 12 weeks . The primary outcome , measured after 12 weeks , was functional capacity assessed by a 6-minute walk test ( 6MWT ) . RESULTS Compared with st and ard care , Nordic walking led to higher functional capacity ( Δ 125.6 ± 59.4 m vs Δ 57.0 ± 71.3 m travelled during 6MWT ; P = 0.001 ) , greater self-reported physical activity ( Δ 158.5 ± 118.5 minutes vs Δ 155.5 ± 125.6 minutes ; P = 0.049 ) , increased right grip strength ( Δ 2.3 ± 3.5 kg vs Δ 0.3 ± 3.1 kg ; P = 0.026 ) , and fewer depressive symptoms ( Hospital Anxiety and Depression Scale score = Δ -1.7 ± 2.4 vs Δ -0.8 ± 3.1 ; P = 0.014 ) . No significant differences were found for peak aerobic capacity , left-h and grip strength , body weight , waist circumference , or symptoms of anxiety . CONCLUSIONS Nordic walking was superior to st and ard cardiac rehabilitation care  in improving functional capacity and other important outcomes in patients with heart failure . This exercise modality is a promising alternative for this population 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 Question naire , 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 data base from the FAIR-HF trial , which r and omized 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 Question naire , 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 RATIONALE The 6-minute-walk test ( 6MWT ) is a practical and clinical ly meaningful measure of exercise tolerance with favorable performance characteristics in various cardiac and pulmonary diseases . Performance characteristics in patients with idiopathic pulmonary fibrosis ( IPF ) have not been systematic ally evaluated . OBJECTIVES To assess the reliability , validity , and responsiveness of the 6MWT and estimate the minimal clinical ly important difference ( MCID ) in patients with IPF . METHODS The study population included all subjects completing a 6MWT in a clinical trial evaluating interferon gamma-1b ( n = 822 ) .  Six-minute walk distance ( 6MWD )  and other parameters were measured at baseline and at 24-week intervals using a st and ardized protocol . Parametric and distribution-independent correlation coefficients were used to assess the strength of the relationships between 6MWD and measures of pulmonary function , dyspnea , and health-related quality of life . Both distribution-based and anchor-based methods were used to estimate the MCID . MEASUREMENTS AND MAIN RESULTS Comparison of two proximal measures of 6MWD ( mean interval , 24 d ) demonstrated good reliability ( coefficient = 0.83 ; P < 0.001 ) . 6MWD was weakly correlated with measures of physiologic function and health-related quality of life ; however , values were consistently and significantly lower for patients with the poorest functional status , suggesting good construct validity . Importantly , change in 6MWD was highly predictive of mortality ; a 24-week decline of greater than 50 m was associated with a fourfold increase in risk of death at 1 year ( hazard ratio , 4.27 ; 95 % confidence interval , 2.57- 7.10 ; P < 0.001 ) . The estimated MCID was 24 - 45 m. CONCLUSIONS The 6MWT is a reliable , valid , and responsive measure of disease status and a valid endpoint for clinical trials in IPF PURPOSE The purpose of this study was to use an accelerometer to measure daily walking  performance in patients with chronic heart failure ( CHF ) to investigate if this parameter is a determinant of New York Heart Association class and indicative of maximal and functional exercise capacity . METHODS Fifty patients with CHF were instructed to wear an accelerometer for 7 consecutive days while going about their daily business . Maximal and functional exercise capacity was assessed by cardiopulmonary ( VO(2peak ) ) and 6-minute walk testing , respectively . RESULTS Patients in New York Heart Association I , II , and III reached an average total walking time ( TWT ) of 160.6 + /- 35.8 minutes , 133.9 + /- 59.0 minutes , and 76.1 + /- 22.5 minutes per day of which 19 % , 19 % , and 9 % where spent in the fast walking mode ( > 83 m/minute ) , respectively . The TWT correlated strongly with VO(2peak ) ( r = 0.72 ; P < .001 ) and 6-minute walk testing distance ( r = 0.68 ; P < .001 ) . The TWT and time spent in fast walking mode were the strongest determinants in discriminating moderate CHF . CONCLUSION Daily walking performance is a clear determinant of maximal and functional exercise capacities in patients with CHF .  Walking intensity in particular is an independent predictor in discriminating patients with advanced heart failure . Monitoring of daily walking performance might aid in detecting disease progression and improve clinical outcome Six-minute walk distance ( 6MWD ) is commonly used as a measure of functional exercise capacity in clinical practice and research . Regression equations to predict 6MWD in healthy individuals are available , but the equations predict distances that vary considerably for an individual . The aims of this study were to 1 ) measure 6MWDs in healthy Caucasian Australians aged 45 - 85 years ; 2 ) determine whether evidence exists for Australian-specific prediction equations for Caucasian individuals by comparing measured 6MWDs with predicted 6MWDs derived by using published regression equations ; and 3 ) develop regression equations for males and females . One hundred nine subjects ( 48 males ) completed the 6-minute walk test ( 6MWT ) . Measurements of height , leg length , weight , habitual physical activity , and peak heart rate ( HR ) achieved during the 6MWT were obtained . 6MWD ( better of two tests ) was 682 ± 73 m ( mean ± SD ) and 643 ± 70 m in the males and females , respectively ( p<0.01 ) . Published regression equations underestimated 6MWDs in female subjects . Gender-specific regression equations using age and anthropometric data explained 40 % and 43 % of the variance in 6MWD in males and females , respectively . Validation of the regression equations in a prospect i ve subject cohort is required The six-minute walk test ( 6MWT ) has been broadly used in clinical setting s. Several reference equations for prediction of the total distance walked during the test ( 6MWD ) are available in literature . The present review aim ed to critically discuss studies , published in Portuguese and English ( LILACS , SCIELO , MEDLINE , PUBMED ) , which evaluated normal values and created reference equations for predicting 6MWD in healthy subjects , comparing them with the results that were recently obtained in Brazilian individuals . Age , sex , weight , height and body mass index were the main demographic and anthropometric features more often correlated with 6MWD . The equations derived from these characteristics were able to explain between 25 and 66 % of the total variability in the 6MWD . Unfortunately , the foreign equations were not applicable to the Brazilian population . Even when the 6MWT was performed following strict st and ardization , the difference in 6MWT performance between foreign and Brazilian individuals remains , indicating the necessity of providing specific reference equations for each population and /or ethnic group . Accordingly , these equations developed in Brazil are probably the most appropriate for interpreting 6MWT performance in Brazilian patients with chronic diseases affecting the exercise capacity . Future studies are necessary with larger sample sizes ( e.g. multicentric ones ) and r and omized design for the reference values of the 6MWD to be considered reliable
Comparison of the studies investigating reliability shows that the 6MWT has good reproducibility .
The 6MWT demonstrates moderate correlation with peak VO(2 ) levels , and ability to predict VO(2 ) ( functional capacity ) dependent on distance walked .
Cut-off distances vary from 300 to 490 meters depending on the study ; if total distance walked remains equal or less than these values , the 6MWT retains its strong predictive value .
The 6MWT has good reliability , moderate validity , and a significant ability to predict functional capacity in patients with CHF who do not walk greater than 490 meters
PURPOSE To evaluate the reliability and validity of the six-minute walk test ( 6MWT ) with respect to its ability to predict functional capacity in patients with chronic heart failure .