Walk Test In Individuals Research Articles

Reliability and Validity of 3-Meter Backward Walk Test in Individuals with Balance Impairments: A Literature Review

Reliability and Validity of 3-Meter Backward Walk Test in Individuals with Balance Impairments: A Literature Review

Cardiorespiratory fitness in individuals with type 2 diabetes mellitus: a systematic review and meta-analysis.

To conduct a systematic review and meta-analysis assessing the cardiorespiratory fitness (CRF) among individuals with and without type 2 diabetes. The current review was registered in PROSPERO under the number CRD42018082718. MEDLINE, EMBASE, and Cochrane Library databases were searched from inception through February 2022. Eligibility criteria consisted of observational or interventional studies that evaluated CRF through cardiopulmonary exercise testing or six-minute walk test in individuals with type 2 diabetes compared with individuals without type 2 diabetes. For data extraction, we used baseline CRF assessments of randomized clinical trials or follow-up CRF assessments in observational studies. We performed a meta-analysis using maximal oxygen consumption (VO2 max), and distance walked in the 6MWT as primary outcomes. They were extracted and expressed as mean differences (MDs) and 95% CIs between treatment and comparator groups. The meta-analysis was conducted using Review Manager (RevMan) software. Out of 8,347 studies retrieved, 77 were included. Compared with individuals without type 2 diabetes, individuals with diabetes achieved a lower VO2 max (-5.84 mL.kg-1.min-1, 95% CI -6.93, -4.76 mL.kg-1.min-1, p = <0.0001; I2 = 91%, p for heterogeneity < 0.0001), and a smaller distance walked in 6MWT (-93.30 meters, 95% CI -141.2, -45.4 meters, p > 0.0001; I2: 94%, p for heterogeneity < 0.0001). Type 2 diabetes was associated with lower cardiorespiratory fitness, as observed by lower VO2 max on maximal tests, and smaller distance walked in 6MWT, however the quality of studies was low.

Concurrent validity of walking speed measured by a wearable sensor and a stopwatch during the 10-meter walk test in individuals with stroke

BackgroundWalking speed is often measured with a stopwatch throughout stroke recovery. Wearable sensors also have been used recently to measure walking speed and provide information about spatiotemporal characteristics of walking.Research Question:Do walking speeds measured with stopwatch and APDM wearable sensors have concurrent validity? MethodsIndividuals with chronic stroke (n = 62) performed the 10-meter walk test at comfortable and maximal speeds. Walking speeds were measured with a stopwatch and APDM Opal wireless wearable sensors (3-unit). Tests of concurrent validity between stopwatch and APDM (Bland-Altman plots, systematic and proportional bias, and intraclass correlations) and test-retest reliability between trials (intraclass correlations, standard error of measurement, and minimal detectable change) were performed. ResultsWalking speeds measured with APDM were ∼0.07 m/s slower than those measured with stopwatch (systematic bias; t ≥ 13.1, p < 0.001). Intraclass correlations ranged from poor to excellent. There were greater differences in walking speeds between APDM and stopwatch for individuals with faster walking speeds (proportional bias). Test-retest reliability was excellent for both APDM and stopwatch (intraclass correlation≥0.94). Standard error of measurement ranged from 0.04 to 0.07 m/s and minimal detectable change ranged from 0.10 to 0.19 m/s.Significance:It may be inappropriate to use walking speed measurements from APDM sensors and stopwatch interchangeably in individuals with chronic stroke. Differences in walking speeds may reflect stopwatch error or the derivation of walking speed from wearable sensors. Test-retest reliability was excellent for both stopwatch and APDM, but minimal detectable change values were large. Large changes in walking speed may be required to be confident that the change is a true and clinically meaningful change and not measurement error. The validity and reliability of measuring walking speed with wearable sensors in individuals with chronic stroke has important implications for determining community ambulation, assessing improvements after rehabilitation, and developing exercise prescriptions.

Minimally Important Difference of the 20-m 6-Minute Walk Test in Individuals With COPD.

The 20-m 6-min-walk test (6MWT20) is a valid, reliable alternative for functional capacity assessment; however, its responsiveness and minimally important difference (MID) have yet to be investigated. The aim of this study was to assess the responsiveness and MID of the 6MWT20 in individuals with COPD. Fifty-three subjects completed the study from August 2011-March 2020. The following were assessed: lung function, activities of daily living (ADLs), functional capacity 6MWT20, dyspnea, health status, quality of life, and limitations in ADLs. The primary outcome was the 6MWT20 distance. The study demonstrated that the 6MWT20 is responsive to pulmonary rehabilitation (PR), with an average improvement of 39 ± 36.3 m (P < .001) and an effect size of 1.07. The learning effect declined to 1.45% after PR, with an intraclass correlation coefficient of 0.99 (95% CI 0.98-0.99). The receiver operating characteristic curve indicated a cutoff point of 20 m for the MID of the 6MWT20 based on the MIDs for the modified St George Respiratory Questionnaire (sensitivity 87%, specificity 69%, area under the curve 0.80 [95% CI 0.66-0.90], P < .001, Youden index 0.56) and the number of steps (sensitivity 92%, specificity 73%, area under the curve 0.83 [95% CI 0.70-0.92], P < .01, Youden index 0.56). The 6MWT20 is responsive to PR, and the MID for the test is 20 m (17-47 m).

Validity and reliability of the 2-minute walk test in individuals with spinal cord injury

Study designMulticentre-observational study.ObjectivesThe 6-minute walk test (6mWT) is an established assessment of walking function in individuals with spinal cord injury (SCI). However, walking 6 min can be demanding for severely impaired individuals. The 2-minute walk test (2mWT) could be an appropriate alternative that has already been validated in other neurological disorders. The aim of this study was to assess construct validity and test-rest reliability of the 2mWT in individuals with SCI. In addition, the influence of walking performance on sensitivity to change of the 2mWT was assessed.SettingSwiss Paraplegic Center Nottwil, Switzerland; Balgrist University Hospital, Zürich, Switzerland.MethodsFifty individuals (aged 18–79) with SCI (neurological level of injury: C1-L3, AIS: A-D) were assessed on two test days separated by 1 to 7 days. The first assessment consisted of a 2mWT familiarization, followed by a 2mWT and 10-meter walk test (10MWT) (including the Walking Index for Spinal Cord Injury (WISCI II)) in randomized order. The second assessment consisted of 2mWT and 6mWT in randomized order. Tests were separated by at least 30 min of rest.ResultsThe interclass correlation coefficient between the 2mWT assessed on the first and second test day was excellent (r = 0.980, p < 0.001). The 2mWT correlated very strongly with the 6mWT (r = 0.992, p < 0.001) and the 10MWT (r = 0.964, p < 0.001), and moderately with the WISCI II (r = 0.571, p < 0.001). Sensitivity to change was slightly affected by walking performance.ConclusionThe 2mWT is a valid and reliable alternative to the 6mWT to measure walking function in individuals with SCI.Trial registrationNCT04555759.

Genetic subgroup learnings from MMPOWER-3 trial: Elamipretide improved six-minute walk test in individuals with mtDNA replisome disorders

Genetic subgroup learnings from MMPOWER-3 trial: Elamipretide improved six-minute walk test in individuals with mtDNA replisome disorders

Impact of resistance training on the 6-minute walk test in individuals with chronic obstructive pulmonary disease: A systematic review and meta-analysis.

The aim of this systematic review was to assess functional improvement, measured by the 6-minute walk test (6MWT) after the application of a resistance training (RT) protocol in people with chronic obstructive pulmonary disease (COPD). The search involved the databases ClinicalTrials.gov, Cochrane Central Register of Controlled Trials, EMBASE, PubMed and Scopus from the beginning of inception to September 1, 2019. Randomized controlled trials evaluating the functional impact of RT were included. The quality of the trials was assessed with the Physiotherapy Evidence Database (PEDro) scale. Calculations were performed according to mean difference (MD) for differences between pre- and post-intervention in 6MWT distance and according to the standardized mean difference (SMD) for post-treatment results of the 6MWT and quadriceps muscle strength (QMS) improvement. In total, 23 studies (690 patients) met the inclusion criteria. Meta-analysis was used to compute the best improvement on the 6MWT with an analysis of improvement pre- versus post-treatment (MD 37.3, 95% confidence interval [CI] 9.8; 64.8, I2=86%, p=0.008) versus post-treatment alone, intervention versus control group (MD 15.5, 95% CI -7.7; 38.6, I2= 71%, p = 0.19). QMS was significantly improved (SMD 2.9, 95% CI 1.1; 4.7, I2= 91%, p = 0.002). The results of the meta-analysis show a significant improvement in walking ability and performance measured by the 6MWT and an improvement in QMS for people with COPD responding to the therapy. The main limitation of this review is the significant heterogeneity across the study results. Furthermore, the statistical significance does not totally coincide with the clinical significance. RT is recommended to reduce muscle dysfunction and seems useful when combined with endurance training.

Six-Minute Walk Test in Individuals With Unilateral Lower Limb Amputations.

Background:The 6-minute walk test (6MWT) is one of the common clinical tests to assess rehabilitation progress and needs in individuals with lower-limb amputation (iLLAs). However, the analysis of this test is mostly limited to the distance parameter. The first aim was to investigate effort intensity and spatiotemporal parameters of 6MWT in iLLAs using inertial measurement units (IMUs) and heart rate (HR) monitor, and second, to assess physical, physiological, and pain-related aspects of fatigue over 6MWT.Methods:Eleven unilateral iLLAs (57.91±15.63 years old) participated in this study. To evaluate HR and spatiotemporal parameters over 6MWT, data were classified using 6 intervals of 1 minute each (I1-I6). The pain level of participants was estimated using the visual analog scale (VAS).Results:Our results showed that the means of normalized HR gradually increased over 6MWT (I1: 61.59±10.73 HRmax%, I6: 70.15±12.26 HRmax%, P = .003). Variability of HR during the first interval of 6MWT was higher than the others (P < .05). The stance ratio of the gait cycle increased over 6MWT (P < .05). Cadence and speed decreased over 6MWT (P < .05). VAS score after 6MWT was significantly higher than before 6MWT (P = .016).Conclusion:In this preliminary study, effort intensity over 6MWT gradually increased because of enhancement of HR. Deterioration of speed and cadence and enhancement of stance ratio over 6MWT imply potential physical aspects of fatigue and instability.Level of Evidence:Level III, retrospective comparative study.

Validity and Reliability of The 3-Meter Backward Walk Test in Individuals with Stroke

ObjectivesThe 3-m backward walk test (3MBWT) is used to evaluate neuromuscular control, proprioception, protective reflexes, fall risk and balance. The aim of our study was to reveal the test-retest reliability and validity of the 3MBWT in stroke patients. Materials and MethodsThis study included a total of 41 stroke patients [age 59 (35–78) years]. 3MBWT, Berg Balance Scale (BBS), Timed Up and Go test (TUG) were applied to the patients. The second evaluation (retest) was carried out by the same physiotherapist two days following the first evaluation (test) in order to measure test-retest reliability. ResultsCronbach's alpha coefficient was found to be 0.974 (excellent). For intra-rater agreement, the ICC values in the individual test were 0.985. The SEM value was 1.11 sec, the MDC value was found to be 1.57 sec. A moderate correlation was revealed between the 3 m-backward walking speed and BBS (r: -0.691, p: 0.001) and TUG (r: 0.849, p: 0.001). ConclusionsThe 3MBWT was observed to be valid and reliable in stroke individuals. It is an effecive and reliable tool for measuring dynamic balance and falls in stroke.

Reliability of the six-minute walk test in individuals with stroke: systematic review and meta-analysis.

The six-minute walking test (6MWT) is a simple and widely used measure of functional capacity. The aim of this systematic review is to summarize findings on reliability of 6MWT in subjects who have had a stroke. Two independent investigators conducted an extensive search in multidisciplinary electronic databases from inception to August 2019, and selected complete original studies on the reliability of the 6MWT used to assess individuals with stroke. Two reviewers independently extracted data and evaluated methodological quality. Outcome for meta-analysis was reliability, measured by intraclass correlation coefficient (ICC). In addition, standard error of measurement (SEM) and minimal detectable change (MDC) were recorded. Of the 241 potentially relevant articles screened, 6 met inclusion criteria and 5 of them were included in meta-analysis. Combined correlation coefficient of .98 (confidence interval .98-.99) was found for test-retest reliability. Only one study investigated inter-rater and intra-rater reliability. SEM and MDC values were rarely reported. The 6MWT has high test-retest reliability, when used to assess individuals with stroke. Other types of reliability and SEM and MDC need further investigations in populations with a stroke.

The minimal important difference for the endurance shuttle walk test in individuals with chronic obstructive pulmonary disease following a course of pulmonary rehabilitation

The endurance shuttle walk test (ESWT) is frequently used as an outcome measure for pulmonary rehabilitation (PR). The minimal important difference (MID) for the ESWT after a course of rehabilitation has not been conclusively confirmed in the literature. The aim was to establish the MID for the ESWT following the 6-week PR programme in patients with chronic obstructive pulmonary disease (COPD). Following the completion of the 6-week PR programme, data from 531 participants were included in the analysis to estimate the MID for the ESWT using both anchor-based and distribution-based methods. Mean age (standard deviation (SD)) was 69.4 (9.1) years, 303 male, FEV1/FVC 0.51 (0.16). The baseline incremental shuttle walk test (ISWT) was 217.7 (SD 139.8) metres and ESWT 195.8 (SD 118.8) seconds, which increased to 279.6 (SD 149.5) metres and 537.4 (SD 378.3) seconds, respectively, following PR. The mean change was 61.8 (95% confidence interval (CI) 56.0–67.5) metres for the ISWT and 342.0 (95% CI 312.4–371.6) seconds for the ESWT. The distribution method (0.5 × SD) yielded an MID of 173.7 seconds, the global rating of change scale method yielded a value of 279.2 (95% CI 244.9–313.5) seconds for those rating themselves as ‘slightly improved’ and the ROC method 207 seconds. There was no agreement between the approaches employed. However, we propose that the MID for the ESWT in COPD following a 6-week PR programme is between 174 and 279 seconds.

Reliability and Validity of the 6 Minute Walk Test in Individuals with Facioscapulohumeral Dystrophy (P3.120)

Reliability and Validity of the 6 Minute Walk Test in Individuals with Facioscapulohumeral Dystrophy (P3.120)

Multidirectional walk test in individuals with Parkinson's disease: a validity study.

Gait parameters of forward, backward, and sideways walk were studied when the participants walked overground in four directions at their self-selected speed and were compared with walking in the four directions on an instrumented GAITRite walkway. Intraclass correlation coefficients between the overground walk test measures and the instrumented walkway measures of gait speed, cadence, and stride length for the forward walk were 0.85, 0.88, and 0.87, respectively. For the backward walk, the coefficients were 0.91 for gait speed, 0.75 for cadence, and 0.93 for stride length. For the sideways walk, the coefficients were 0.92 for gait speed, 0.93 for cadence, and 0.94 for stride length. Gait parameters of forward, backward, and sideways walk obtained by the overground walk test had excellent agreement with those obtained by the instrumented walkway. The quick timed test provided quantitative data for gait evaluation and was valid for clinical use.

Cytokine response to the 6-min walk test in individuals with different degrees of COPD.

Physical exercise is a key part of rehabilitation programs in chronic obstructive pulmonary disease (COPD) patients, although it could modulates immune system responses by altering the cytokine profile of such individuals. Furthermore, the degree of severity of COPD could influence the inflammatory response induced by exercise. To evaluate the cytokine profile of individuals with different degrees of COPD in response to a 6-min walk test (6MWT). Forty-one patients with COPD were classified according to the severity of the disease by Global Initiative for Chronic Obstructive Lung Disease method: moderate = 14 individuals; severe = 14 individuals; very severe = 13 individuals. Blood sample collection was performed in the subjects pre and post a 6MWT. Cytokine plasma levels were analyzed to determine the cytokine profile using a Cytometric Bead Array technique (Becton Dickinson, San Jose, CA, USA) assay in flow cytometry. A significant difference was observed in the interleukin (IL)-6 levels after test between very severe and severe groups (P = 0.036). Also, lower levels of IL-4 were observed in the severe group compared with the very severe and the moderate groups in the pretest (P = 0.029; P = 0.003, respectively), and different values between the moderate and severe groups in the post-test (P = 0.044). A significant time pre-post effect was found in the IL-4 levels on the very severe group (P = 0.046). After the 6MWT, a discrete inflammatory response was observed in COPD patients, independent of the degree of severity. The results concerning IL-4 and IL-6 levels can be indicative of an attempt to control inflammation after the 6MWT in COPD patients.

Reliability of the Non-Instrumented Walk Test in Persons with Parkinson’s disease

Purpose: To study the reliability of a Non-Instrumented Walk Test in individuals with Parkinson’s disease (PD). Method: Thirty individuals (21 Males) with PD were studied. Their mean age was 68.90 ± 9.28 years. The average time since diagnosis was 8.75 ± 5.68 years. The reliability of the manual Non-Instrumented Walk Test was studied while “OFF” and “ON” dopaminergic medication. Subjects walked at their self-selected, usual speed during a Non-Instrumented Walk Test and while walking on a computerized instrumented walkway. Intraclass correlation coefficients (ICCs) were calculated and means were compared for three gait parameters as measured by the two methods. Results: During “OFF” medication testing, ICCs between the Non-Instrumented Walk Test and the instrumented measures for gait speed, cadence and stride length were 0.96 (p < 0.0005), 0.72 (p = 0.001) and 0.97 (p < 0.0005), respectively. During “ON” medication testing, the ICCs were 0.96 (p < 0.0005), 0.86 (p < 0.0005) and 0.96 (p < 0.0005), respectively. The means of the non-instrumented measures tended to be lower than those obtained on the instrumented walkway. Conclusions: The Non-Instrumented Walk Test is a quick, simple and inexpensive gait evaluation for individuals with PD. The method is sufficiently reliable to be used clinically in this population during different medication cycles.Implications for RehabilitationThe Non-Instrumented Walk Test in individuals with PD is reliable.Results supported the use of the measure. This simple walk test is quick and easy to administer in both clinical and community settings.

Test-Retest Reliability of the 6-Minute Walk Test in Individuals With Down Syndrome

Casey AF, Wang X, Osterling K. Test-retest reliability of the 6-minute walk test in individuals with Down syndrome. ObjectivesTo evaluate the reliability of the 6-minute walk test (6MWT) in individuals with Down syndrome and explore factors affecting walking distance. DesignFour repeated walk tests in the span of 2 weeks including 2 practice walks. SettingAll tests were carried out in a 40-meter corridor at a university sport complex. ParticipantsAdolescents and young adults with Down syndrome (N=55) aged 11 to 26 years. InterventionNot applicable. Main Outcome MeasureParticipants were instructed to walk as far as possible for the duration of 6 minutes. Distance walked, heart rate, blood pressure, and perceived exertion were measured across 4 tests (t1, t2, t3, and t4). ResultsThe walking distances for t1, t2, t3, and t4 averaged 395, 428, 433, and 436 meters, respectively. The 6-minute walk distance (6MWD) during t1 and t2 was significantly different from that during t3 and t4 (t54=−6.475, P<.001). Repeated analysis of variance showed no significant difference between the distance walked in t3 and t4 (433±64m vs 436±68m) (F1,54=2.439, P=.124). Body mass index as well as levels of intellectual disability and physical activity all affected the distance walked to different degrees. ConclusionsThe 6MWT showed good test-retest reliability and increased the walking distance after 2 practice walks, emphasizing the need to account for a learning effect among people with Down syndrome. Reported 6MWD appears lower than that previously reported for individuals without Down syndrome.

Minimal Detectable Changes of the Berg Balance Scale, Fugl-Meyer Assessment Scale, Timed “Up & Go” Test, Gait Speeds, and 2-Minute Walk Test in Individuals With Chronic Stroke With Different Degrees of Ankle Plantarflexor Tone

Hiengkaew V, Jitaree K, Chaiyawat P. Minimal detectable changes of the Berg Balance Scale, Fugl-Meyer Assessment Scale, Timed “Up & Go” Test, gait speeds, and 2-minute walk test in individuals with chronic stroke with different degrees of ankle plantarflexor tone. ObjectiveTo determine test-retest reliability and absolute and relative minimal detectable changes at the 95% confidence level (MDC95) of measures to detect postural balance and lower limb movements in individuals with chronic stroke who were able to walk and had differences in ankle plantarflexor tone. DesignTest-retest study. Data were collected on 2 occasions, about 6 days apart. SettingOutpatient physical therapy clinics. ParticipantsVolunteers (N=61) with chronic stroke who were able to walk and had differences in ankle plantarflexor tone: no increase in ankle plantarflexor tone (n=12), a slight increase in ankle plantarflexor tone (n=32), and a marked increase in ankle plantarflexor tone (n=17). InterventionNot applicable. Main Outcome MeasuresReliability and absolute and relative MDC95 of the Berg Balance Scale (BBS), the lower limb subscale of Fugl-Meyer Assessment (FMA-LE), the Timed “Up & Go” test (TUG), the comfortable gait speed (CGS), the fast gait speed (FGS), and the 2-minute walk test (2MWT). ResultsExcellent reliability of the BBS, FMA-LE, TUG, CGS, FGS, and 2MWT for all the participants combined and for the subgroups was shown. All the participants combined showed the absolute and relative MDC95 in the BBS of 5 points and 10%, FMA-LE of 4 points and 16%, TUG of 8 seconds and 28%, CGS of 0.2m/s and 34%, FGS of 0.1m/s and 21%, and 2MWT of 13m and 23%. The absolute and relative MDC95 of the subgroups were varied based on ankle plantarflexor tone. ConclusionsThe BBS, FMA-LE, TUG, CGS, FGS, and 2MWT are reliable measures to detect postural balance and lower limb movements in individuals with chronic stroke who have differences in ankle plantarflexor tone. The absolute and relative MDC95 of each measure are dissimilar in those with differences in ankle plantarflexor tone. The relative MDC95 seems more useful than the absolute MDC95 because the relative value can be used for a single individual.

Responsiveness and Validity of the Six-Minute Walk Test in Individuals With Traumatic Brain Injury

A simple test of aerobic fitness for patients with traumatic brain injury (TBI) that is valid, reliable, and responsive to change is needed to provide clinicians a functional measure of cardiorespiratory capacity. The purpose of this study was to examine the validity and responsiveness to change of the Six-Minute Walk Test (6MWT) in individuals with TBI. A cohort, pretest-posttest, comparison study was conducted. Twenty-one patients performed the 6MWT upon admission to and prior to discharge from a postacute rehabilitation facility. Heart rate and distance traveled were recorded. A physiologic cost index (PCI) (beats per meter) was calculated based on steady-state heart rate. At discharge, all participants were able to perform a graded treadmill exercise test to exhaustion during which peak oxygen consumption (Vo(2)) was measured. Between admission and discharge, mean total distance increased from 342.6 m (SD=127.0) to 408.9 m (SD=124.2), and work increased from 27,185 kg·m (SD=10,528) to 34,114 kg·m (SD=12,057). The effect size indexes were 1.10 and 1.12 for distance and work, respectively. Correlations (r) between the discharge peak Vo(2) and the discharge 6MWT distance, PCI, and work were .58, -.61, and .47, respectively. Stratification by gait speed may have improved responsiveness, especially for the slow ambulators. All measures correlated well with peak Vo(2), establishing an acceptable level of criterion-related (concurrent) validity. The addition of heart rate and calculating the PCI was only slightly better at predicting peak Vo(2), albeit nonsignificant, than a simple measure of total distance. The 6MWT provides a good estimate of peak aerobic capacity, and some measures are more responsive to change than others in patients recovering from TBI.

Triangulating Clinically Meaningful Change in the Six-minute Walk Test in Individuals with Chronic Heart Failure: A Systematic Review

The purpose of the present review was to use existing, published data to provide an estimate of the amount of change in six-minute walk test distance (Δ6MWT) that represents a clinically meaningful change in individuals with chronic heart failure (CHF). THE PRESENT REVIEW INCLUDED TWO SEPARATE LITERATURE SEARCHES OF THE CINAHL AND MEDLINE DATABASES FOR ARTICLES THAT: (1) reported the intraclass correlation coefficient (ICC) of the 6MWT in individuals with CHF, and (2) used the 6MWT along with either aerobic capacity or health-related quality of life (HRQL) as study endpoints in randomized controlled trials (RCTs) of exercise-based intervention for individuals with CHF. The ICCs were used to calculate the minimum detectable difference (MDD) at the 95% confidence interval for each included study. The Δ6MWT associated with aerobic capacity and HRQL within-group effect sizes for the intervention and control groups in each included RCT was analyzed using receiver operating characteristic (ROC) curves. Thirteen articles reported the ICC for the 6MWT. The mean (standard deviation) MDD calculated based on these data was 43.1(16.8) m. Eighteen RCTs measured the 6MWT and either aerobic capacity and/or HRQL. A Δ6MWT of 40-45 m was associated with at least moderate aerobic capacity and HRQL effect sizes in the intervention groups. The Δ6MWT thresholds that discriminated between intervention and control groups using ROC curves revealed the following sensitivity/specificity for the respective thresholds: 19 m, 94.4/83.3%, 32 m, 83.3/94.4%, and 48 m 44.4/100% (AUC = .935, p = .009, CI(95%) .855, 1.015). A Δ6MWT of approximately 45 m appears to exceed measurement error and be associated with significant changes in either aerobic capacity and/or HRQL.

Measurement properties of the 6‐min walk test in individuals with exercise‐induced pulmonary arterial hypertension

Exercise-induced pulmonary arterial hypertension (EIPAH) is associated with reduced peak exercise cardiac output (CO) and aerobic capacity (peak ). We investigated the validity of the encouraged 6-min walk test (6MWT) to identify exercise limitation and estimate aerobic capacity in subjects with EIPAH. Seventeen subjects with EIPAH (56 ± 14 years, 15 women) and 20 healthy controls (57 ± 13 years, 19 women) underwent two encouraged 6MWTs and a symptom-limited cardiopulmonary exercise test (CPET). To measure central haemodynamics, subjects with EIPAH performed the CPET with a pulmonary artery catheter in situ. Compared with controls, subjects with EIPAH had reduced peak (1.2 ± 0.4 vs 1.7 ± 0.5, L/min, P < 0.01), 6-min walk distance (6MWD) (575 ± 86 vs 669 ± 76 m, P < 0.001) and 6-min walk work (6MWW) (39 ± 11 vs 45 ± 7 km.kg, P < 0.01). In subjects with EIPAH, there was a moderate correlation between 6MWD and peak (r= 0.72, P < 0.01) and a strong correlation between 6MWW and peak (r= 0.86, P < 0.001). There were significant correlations between 6MWD and peak CO (r= 0.59, P < 0.05), and between peak and peak CO (r= 0.55, P < 0.05). Peak heart rate was similar in the CPET and 6MWT in subjects with EIPAH (133 ± 15 vs 133 ± 19 beats/min, P= 0.8). The encouraged 6MWT identifies reduced exercise capacity and provides a valid estimate of aerobic capacity in EIPAH.