Concurrence of 1- and 3-Min Sit-to-Stand Tests with the 6-Min Walk Test in Idiopathic Pulmonary Fibrosis

Abstract

<b><i>Background:</i></b> In idiopathic pulmonary fibrosis (IPF), some physiological parameters measured during a 6-min walk test (6-MWT) impart reliable prognostic information. Sit-to-stand tests (STSTs) are field exercise tests that are easier to implement than the 6-MWT in daily practice. <b><i>Objectives:</i></b> The aims of the study were to test the reproducibility and compare 2 STSTs (the 1-min STST [1-STST] and the semi-paced 3-min chair rise test [3-CRT]) in IPF, and to determine if selected physiological parameters (speed of displacement and changes in pulse oxygen saturation [SpO₂]) are interchangeable between the STSTs and the 6-MWT. <b><i>Methods:</i></b> Thirty-three patients with stable IPF were studied in 3 French expert centers. To test reproducibility, intra-class correlations (ICCs) of parameters measured during tests performed 7–14 days apart were calculated. To test interchangeability, the agreement and correlation of physiological responses measured during STSTs and during 6-MWT were studied. <b><i>Results:</i></b> Vertical displacements and changes in SpO₂ during both STSTs were reproducible, with ICCs ranging from 0.78 [0.63–0.87] to 0.95 [0.92–0.97]. Vertical displacements during 1-STST and 3-CRT were correlated with 6-MWT distance (correlation coefficients (<i>r</i>) of 0.72 and 0.77, respectively; <i>p</i> &#x3c; 0.001). Similarly, correlations were found between changes in SpO₂ measured during the 2 STSTs and the 6-MWT, with coefficients ranging from 0.73 to 0.91 (<i>p</i> &#x3c; 0.001). Distance walked and SpO₂ during 6-MWT were well estimated from vertical displacement and SpO₂ during the 2 STSTs, respectively. <b><i>Conclusion:</i></b> The correlations found between the 2 STSTs and the 6-MWT suggest that STSTs may be of interest to assess displacement and exercise-induced changes in SpO₂ in IPF patients.