Six-minute stepper test for evaluating functional exercise capacity in patients with sarcoidosis

Background: Researchers and clinicians may benefit from alternative tests that do not require large physical spaces or corridors for simply evaluating functional exercise capacity in the clinical practice. Objective: Aim of this study was to investigate whether six-minute stepper test (6MST) is a valid tool for measuring functional exercise capacity in patients with sarcoidosis. Methods: Thirty-six patients with sarcoidosis and 18 healthy controls were evaluated with 6MST and sixminute walk test (6MWT). Patients performed 6MST twice. Cardiovascular and symptom responses to tests including heart rate, blood pressure, SpO(2), levels of dyspnea and fatigue were recorded. Results: Receiver operating characteristic (ROC) curve analysis revealed an area under the ROC curve of 0.74 for 6MST in identifying the patients and controls, indicating acceptable discriminative ability. Patients performed significantly worse in 6MST compared to controls (277 +/- 54 vs 349 +/- 87 steps; p <0.001). 6MST was able to explain 66% of variance in 6MWT (p<0.001), and there was a strong relationship between 6MWT and 6MST (r = 0.812). SpO(2) responses to tests were similar, however, 6MST generated more severe heart rate, dyspnea and fatigue responses. Intraclass correlation coefficient calculated for initial and retest scores of 6MST was 0.990, indicating excellent test-retest reliability. However, there was a systematical improvement (similar to 4%) in retest 6MST scores. Conclusions: 6MST is a valid and reliable alternative test for measuring functional exercise capacity in sarcoidosis. 6MST may also help better testing the upper limits of cardiac system and physical endurance as it is more physically demanding than 6MWT. (C) 2022 Elsevier Inc. All rights reserved.

Automated summary

The study aimed to investigate the validity of the six-minute stepper test (6MST) for measuring functional exercise capacity in patients with sarcoidosis. The results demonstrated that 6MST had acceptable discriminative ability and could explain a significant portion of the variance in the six-minute walk test (6MWT). It was found that 6MST is a valid and reliable alternative test for assessing functional exercise capacity in sarcoidosis patients.