Is there a learning effect when the 6-minute walk test is repeated in people with suspected pulmonary hypertension?

Abstract

The aim of the study was to determine if there was a difference in 6-minute walk distance (6MWD) when two 6-minute walk tests (6MWTs) were performed at the initial assessment prior to attendance at the pulmonary hypertension (PH) clinic and at the 6-month follow-up. Two 6MWTs were performed at both visits on a 32-m continuous track in the physiotherapy hospital outpatient setting using standard instructions and encouragement. Two hundred and fourteen participants completed two 6MWTs at the initial assessment and 71 participants at the 6-month follow-up (mean (standard deviation) age: 57 (16) years; body mass index: 27 (6) kg/m2). Using the better 6MWT, the mean distances walked were 429 (136) and 447 (130) m, respectively. There was a significant increase in 6MWD when a second 6MWT was performed at initial assessment (mean difference [95% confidence interval (CI)]: 19 m (14–24), p < 0.001) and at the follow-up (mean difference [95% CI]: 19 m (10–27), p < 0.001) but not in those who walked <300 m at the initial assessment (mean difference [95% CI]: 9 m (−5 to 22), p = 0.208). There were no adverse events during testing. Prior to attendance at the PH Clinic when people are asked to perform the 6MWT for the first time and at the 6-month follow-up, two walk tests should be performed in order to eliminate a learning effect and to ensure accuracy of measurement.

Intra- and inter-rater reproducibility of the 6-minute walk test and the 30-second sit-to-stand test in patients with severe and very severe COPD

“…The findings in our study group of patients with severe and very severe COPD contradict previous findings of regular systematic bias in studies on heterogeneous groups of patients with varying severity of COPD (stage II–IV/moderate to very severe). 21 , 22 , 24 – 26 , 28 , 46 Without making the reservation that four of the previous studies used 30 minutes of rest between the two test trials and three studies used 24 hours and up to 7 days, their average intra-rater differences ranged from 16 to 37 m. 21 , 22 , 25 , 26 , 28 , 34 , 46 Previous studies on intra-rater reliability have shown learning improvements from the first to the second 6MWT in 70%–82% of the patients while we found improvements in 56% of the patients on T1 and in 62% of the patients from T1 to T2. 22 , 25 – 27 Due to the concern that the learning effect exceeds the minimal important difference (MID) of 30 m documented in previous studies it is currently recommended by the ERS/ATS to complete at least two 6MWT when assessing patients with COPD.…”

“…Results from studies on various patient groups show that patients typically perform better if the 6MWT and 30sec-STS are repeated, indicating that there is a systematic bias, commonly due to a learning effect. 29 – 34 Because learning effect has been an issue of concern in patients with COPD, the recommendation is to use a standardized instruction and to use the highest recorded value from at least two test trials for the 6MWT with a minimum of 30 minutes rest in between test trials. 9 , 10 This recommendation is primarily based on studies on heterogeneous groups of patients with varying severity of COPD (stage II–IV/moderate to very severe).…”

6-minute walking test: a useful tool in the management of heart failure patients

“…The number of laps and the additional distance covered are recorded and the 6MWD is calculated. 5,6 A learning effect has been suggested and two measurements have been proposed at the initial assessment to ensure accuracy; 17 this effect may be less important in older patients with severe respiratory impairment and severe HF. 18…”

Practice effect and cueing of 2-minute walk test, 6-minute walk test and 10-meter walk test in frail older adults with and without dementia - Recommendations to walk tests protocols

“…Significant practice effect associated with the walk tests has been previously reported when the walk tests were repeated on the same occasion or on the same day (Adsett et al, 2011;Gibbons et al, 2010;Jenkins and Cecins, 2010), over consecutive days (Brooks et al, 2002;Hernandes et al, 2011;Kervio et al, 2003) and consecutive weeks (Bohannon et al, 2015;Guyatt et al, 1984) in younger adults with normal cognition. The practice effect has been shown to persist even up to two to six months (Spencer et al, 2018(Spencer et al, , 2008Wu et al, 2003). On the contrary, prior studies on people with chronic lung disease (Eiser et al, 2003) and healthy older adults (Peel and Ballard, 2001) found that the practice effect existed only if the walk tests were repeated on the same occasion, not over an one-week interval.…”