A comparison of informative between 6-minute walking test and sit-to-stand test in patients with fibrosing interstitial lung diseases

Abstract

Physical intolerance is an important sign of many chronic respiratory diseases. The most useful tool for clinical evaluation of physical status is six-minute walking test (6-MWT), but sometimes its technical requirements are not feasible. By this reason, a search for alternative field tests have being going on in the last years, but the diagnostic yield of the new exercise tests for most chronic bronchopulmonary diseases is not clear.The aim of this study was to compare results of 6-MWT and 30-seconds sit-to-stand (30-s-STS) test in patients with fibrosing interstitial lung diseases (ILDs) and restrictive abnormalities of lung function.Methods. This was a cross-sectional non-randomized open comparative study. Patients with ILDs were asked to perform 6-MWT and 30-s-STS test with 30 min interval. We also analyzed medical history, lung function, and dyspnea assessed with Medical Research Council (MRC).Results. The study included 25 ILD patients (11 males; 14 women); 75% of patients had restrictive lung function disorders. The mean distance walked in 6-MWT (6MD) was 380.4 ± 111.9 m (M ± SD), 14 (56%) patients desaturated during the test. The mean number of repetitions in 30-s-STS test was 12 (10 – 13) during 30 s; 5 (20%) patients desaturated during the test. 6MD showed moderate correlation with the number of repetitions in 30-s-STS test and to dyspnea on exertion. The number of repetitions in the 30-s-STS test was not associated with any clinical or functional parameters. To the end of exercise, the number of patients who desaturated increased, the desaturation was greater, and post-exercise SpO2 was lower in 6-MWT compared to 30-s-STS test.Conclusion. 30-s-STS test was less informative in terms of reduced physical tolerance and desaturation on exertion compared to 6-MWT in patients with fibrosing ILDs and restrictive abnormalities of lung function.