Understanding the measurement properties of the incremental shuttle walk test in patients with severe asthma

Abstract

Background and objective:We investigated the repeatability and validity of the incremental shuttle walk test (ISWT) distance compared to peak oxygen uptake (VO 2pk ) during maximal incremental cycle ergometer (ICE) and treadmill (ITM) tests in adults with severe asthma. Methods: Adults with severe asthma, Medical Research Council (MRC) dyspnoea ≥2, were recruited from specialists caring for patients with severe asthma. All participants performed three ISWT (familiarization and two subsequent tests on the same day), an ICE and an ITM in a randomized order, on separate days, to intolerance with expiratory gas analysis. Results: A total of 50 patients (32 females, mean (SD), age: 54 (13) years, forced expiratory volume in 1 s (FEV 1 ): 1.9 (0.8) L and body mass index (BMI): 32 (6) kg/m 2 ) completed all five tests. The mean (SD) ISWT distance for each test was 400 (156), 418 (142) and 438 (157) m (P = 0.001), respectively. There was a strong correlation between the ISWT distance with VO 2pk derived from ITM (r = 0.74, P < 0.001) and ICE (r = 0.75, P < 0.001). Conclusion: There was a small increase in the mean ISWT distance on sequential testing. In clinical practice, the coefficient of repeatability and heteroscedasticity need to be considered when assessing whether a true change has occurred within an individual patient. The ISWT has validity compared to VO 2pk on both ICE and ITM, but they are not interchangeable.

Modified Shuttle Test Distance Correlates With Peak Oxygen Uptake in Children and Adolescents With Severe Therapy-Resistant Asthma

“…Although several studies (Bradley et al, 1999; Vallier et al, 2016; Lanza et al, 2018; Majd et al, 2019) have shown a good association between maximal oxygen consumption (VO 2 peak) measured during CPET and the distance covered in the MST in adults, little is known for pediatric populations. Evidence suggests differences in both exercise capacity parameters and clinical characteristics of asthma between children and adults (Jenkins et al, 2003; Vinet et al, 2003).…”

Contemporary Concise Review 2019: Asthma

“…Subjects with asthma perceived themselves as unfit and were not confident with exercise, but they performed all the IST well, with a learned incremental increase seen between the three tests. The IST also correlated with the calculated and validated, but more complex, cardiopulmonary exercise test‐derived peak oxygen uptake (VO 2Pk ) …”

“…Exercise capacity and activity are frequently reduced in asthma of all severities, especially those with severe disease, yet as mentioned, this is often not measured, with reproducible, accurate but also practical measures required. A team of UK‐based researchers investigated the incremental shuttle walk test (IST), a field test, against the more involved and specialized cardiopulmonary exercise test in adults with severe asthma . Subjects with asthma perceived themselves as unfit and were not confident with exercise, but they performed all the IST well, with a learned incremental increase seen between the three tests.…”

Incremental shuttle walking test in patients with asthma: Shedding light on its measurement properties

“…We read with interest the study of Majd et al regarding the measurement properties of incremental shuttle walking test (ISWT) in patients with asthma. 1 In this elegant and well-designed study, authors investigated the reproducibility of ISWT and the correlation of ISWT distance with peak oxygen uptake values among patients with asthma. Exercise intolerance and reduced physical activity are common in this patient population, and current literature indicates that exercise training is an efficient adjunctive therapy among asthmatic patients.…”