Validation and Cardiorespiratory Response of the 1-Min Sit-to-Stand Test in Interstitial Lung Disease

Abstract

Purpose To assess the 1-min sit-to-stand test (1STS) test-retest reliability and construct validity and its associated cardiorespiratory response in comparison to the 6-min walk test (6MWT) and symptom-limited cycling cardiopulmonary exercise test (CPET) in people with interstitial lung disease (ILD). Methods Fifteen participants with ILD performed two 1STS tests, a 6MWT and a CPET. The three tests were administered on three separate visits, and cardiorespiratory parameters were continuously recorded during the tests. Results The number of repetitions during both 1STS tests was 22 +/- 4 and 22 +/- 4 (mean difference of 0.53 +/- 2.00 repetitions, P = 0.32) with an intraclass correlation of 0.937 (95% confidence interval, 0.811-0.979]) and a minimal detectable change of 2.9 repetitions. The number of 1STS repetitions was highly correlated with the 6MWT distance (r = 0.823, P < 0.001) and with the peak cycling power output expressed in % predicted values (r = 0.706, P < 0.003). Oxygen consumption (VO2) peak during the 1STS reached 83% and 78% of VO2 peak during 6MWT and CPET, respectively. Peak 1STS HR, minute ventilation (V-E,), VO2 values, as well as nadir SpO(2) were achieved during the recovery phase of the test, whereas peak 6MWT and CPET HR, V-E, VO2 and nadir SpO(2) always occurred at the end of the test. The three tests elicited a similar fall in SpO(2) ranging between 8% and 12%. Symptom scores after the 1STS were similar to those seen at the end of the 6MWT but lower than those of CPET. Conclusions The 1STS showed excellent test-retest reliability in patients with ILD in whom it elicited a substantial, but submaximal cardiorespiratory response. Our data also support the construct validity of the 1STS to assess functional exercise capacity in patients with ILD and to detect exercise-induced O-2 desaturation.