Photo Credit: humonia
The following is a summary of “Reliability and validity of the Chester step test in patients with interstitial lung disease,” published in the November 2024 issue of Pulmonology by Alves et al.
Researchers conducted a retrospective study to evaluate the measurement properties of the Chester Step Test (CST) in patients with interstitial lung diseases (ILD).
They assessed patients with ILD using the CST and the 6-minute walk test (6MWT). Participants performed the 1st CST (CST-1) and 6MWT, followed by a 2nd CST (CST-2) after 48–72 hours, with a second rater observing one session. Relative reliability was measured using intraclass correlation coefficients (ICC1,1 and ICC2,1), and absolute reliability was assessed through the standard error of measurement (SEM), minimal detectable change at 95% CI (MDC95), and the Bland-Altman method. The SEM and MDC95 were also expressed as percentages of the mean. Construct validity was explored by correlating the number of steps in the best CST with the distance covered in the 6MWT using the Spearman correlation coefficient (rs).
The results showed 66 patients with ILD, with a mean age of 65.5 ± 12.9 years, 48.5% men, forced vital capacity (FVC) of 79.4 ± 18. pp, and diffusing capacity for carbon monoxide (DLCO) of 49.0 ± 18.3 pp. Relative reliability had intraclass correlation coefficients (ICC) ranging from 0.95 to 1.0, and absolute reliability metrics demonstrated excellent outcomes with no systematic bias. The SEM was 11.8 steps (14.7%), while the minimal detectable change at MDC95 was 32.6 steps (40.7%). A significant, positive, and strong correlation was observed between the CST and the 6MWT, with a Spearman correlation coefficient of 0.85 (P =0.001).
Investigators concluded the CST as a reliable and valid test for assessing exercise capacity, particularly in patients with ILD in limited space environments.
Source: sciencedirect.com/science/article/pii/S2531043722002549
