The relationship of sit-to-stand tests with 6-minute walk test in children with chronic respiratory diseases

<bold>Background:</bold> The sit-to-stand tests have been reported as a valid method of assessing functional exercise capacity, as it can elicit sub-maximal effort, in both clinical and research setting in children with cystic fibrosis (CF) and bronchiectasis. However, findings in asthma, primary ciliary dyskinesia (PCD), and Kartagener's syndrome (KS), which have heterogeneous clinical presentation and progression, are limited. The present study aimed to investigate the relationship of the 1-minute sit-to-stand test (1mSTS) and 30-seconds sit-to-stand test (30sSTS) with 6-minute walk test (6MWT) in children with chronic respiratory diseases. <bold>Method:</bold> A total of 159 children (mean age: 11.74±3.41 years) with chronic respiratory diseases (asthma n=40, PCD n=28, KS n=21, CF n=31, and idiopathic/postinfectious bronchiectasis n=39) were assessed with 1mSTS, 30sSTS, and 6MWT. Fatigue and dyspnea were rated using Borg category-ratio scale (CR10) before and after each test. <bold>Results:</bold> The 1mSTS and 30sSTS were moderately correlated with 6MWT in children with asthma (r=0.601, r=0.637, respectively) and PCD (r=0.680, r=0.682, respectively); and strongly correlated with 6MWT in children with KS (r=0.811, r=0.823, respectively), CF (r=0.865, r=0.847, respectively), and idiopathic/postinfectious bronchiectasis (r=0.851, r=0.828, respectively) (p<0.001). <bold>Conclusion:</bold> Considering the values of correlation, KS, CF, and idiopathic/postinfectious bronchiectasis may further impair functional exercise capacity compared to asthma and PCD. The present study showed that both 1mSTS and 30sSTS may be used as a valid and alternative measurement of functional exercise capacity in children with chronic respiratory diseases.