Assessment of the feasibility of 1-min sit-to-stand test in evaluating functional exercise capacity in interstitial lung disease patients

Six-min walk test (6MWT) is widely used exercise test for the evaluation of interstitial lung disease (ILD). However, the long test duration and need for long and flat surface hinder its routine use. One-min sit-to-stand test (1-STST) is devoid of such limitations, but has been scarcely evaluated. The study was conducted to evaluate the performance of 1-STST by correlating it with 6MWT in ILD patients. Stable ILD patients were prospectively enrolled. After initial spirometry, all patients performed 6MWT and 1-STST following the standard recommendations. Exercise capacity and physiological parameters (heart rate, pulse oxygen saturation, blood pressure and dyspnea [modified Borg scale]) including peripheral oxygen saturation (SpO2) were correlated after the tests using Pearson correlation, Intraclass correlation coefficient (ICC) and kappa (κ) coefficient. The results showed that the mean age of the patients (n= 60) was 58.8± 11.5 years (male:female= 1:1). Repetitions after 1-STST showed significant correlation with 6MWT (r = 0.48; P< 0.001). Changes in the physiological variables were similar (P> 0.05) with good consistency (ICC= 0.68–0.95) between 6MWT and 1-STST. Both lowest SpO2 and difference in SpO2 also showed good agreement (ICC= 0.86; 95% confidence interval [CI], 0.77–0.92 and ICC= 0.68; 95% CI, 0.47–0.81 respectively) and significant correlation (r = 0.76 and r= 0.52, respectively). 1-STST and 6MWT were consistent in identifying patients having oxygen desaturation ≥ 4% (κ= 0.56; 96% CI, 0.30–0.82). The results demonstrated that the performance of 1-STST was consistent with 6MWT in terms of exercise capacity and change in physiological parameters. 1-STST can be a valid alternative to 6MWT in the assessment of ILD patients, especially in peripheral health centers.