The 1-minute sit-to-stand test to evaluate fibrotic interstitial lung disease

Fibrotic interstitial lung diseases (ILD) are a heterogeneous group of conditions. Progression criteria include clinical, imaging, and/or lung functional decline. Currently, the 6-min walk test (6MWT) is considered the gold standard for assessing exercise-induced desaturation. The 1-min sit-to-stand test (1STST) has the advantage of being easy to perform, making it feasible for use during clinical consultations. The aim of this study was to compare the 1STST with the 6MWT in patients with fibrotic ILD to detect exercise-induced desaturation.

A multicenter cross-sectional involved patients with fibrotic ILDs from two centers. The 6MWT and 1STST were performed with a 30-min rest period between the tests. The modified Borg scale was used to assess dyspnea and lower limb fatigue and continuous SpO2 and heart rate were monitored. Desaturation was defined as SpO2 < 90 % or decline >3 %.

Ninety patients were included. The median walking distance in the 6MWT was 432 m and the median number of repetitions in the 1STST was 22, with a significant correlation (p < 0.001, ρ = 0.383). In addition, the minimum SpO2 and the desaturation levels recorded during the tests exhibited a moderate significant correlation (p < 0.001, ρ = 0.502 and p < 0.001, ρ = 0.537, respectively). There was a strong association between the increase in Borg score for dyspnea and a moderate association between the increase in Borg score for lower limb fatigue after both tests (p < 0.001, ρ = 0.706 and p < 0.001, ρ = 0.656, respectively).

This study demonstrates a significant correlation between the 6MWT and the 1STST in detecting exercise-induced desaturation.