Validity of the six-minute step test of free cadence in patients with chronic obstructive pulmonary disease

Abstract

Objectives: to evaluate the concurrent validity of the six-minute step test (6MST) in assessing exercise capacity of COPD patients using the six-minute walk test (6MWT) as a gold-standard. The predictive validity of the 6MST was assessed to determine a cut-off point for identification of low exercise capacity. Method: thirty-two COPD patients (50-87 years old) with mild to very severe obstruction performed the 6MST and 6MWT twice. Results:Concurrent validity: a strong positive correlation (Pearson) between the number of ascents on the first (T1), second (T2) and the best of both (T1 or T2) tests during the 6MWT was observed. Although a moderate negative correlation with BODE index and FEV1 was found, it was considered insufficient to test the validity, therefore ROC curves were not applied. The predictive validity (ROC) of the 6MST to identify low physical capacity (compared with the 6MWT) using the performance of T1 or T2, or solely T1 was considered accurate, and the area under the curve was 0.8 (IC95% 0.62-0.98) and 0.85 (IC95% 0.70-0.99), respectively. To classify patients, the cut-off points of 86 and 78 steps were chosen, with both values showing 90% of sensitivity and specificity of 64% and 68% for T1 or T2, or solely T1, respectively. Conclusion: The number of steps on the 6MST was valid to verify exercise capacity in COPD patients and the cut-off point of 78 steps was able to identify patients with poor exercise tolerance. Values under this cut-off point are considered to identify patients with a poorer prognosis.

Exercise Capacity Impairment Can Predict Postoperative Pulmonary Complications after Liver Transplantation

“…The 6MST has been used to assess exercise capacity in patients with chronic obstructive lung disease and interstitial lung disease, but, to the best of our knowledge, has not been previously evaluated in ESLD subjects [10,11] .…”

Simple Lower Limb Functional Tests in Patients With Chronic Obstructive Pulmonary Disease: A Systematic Review

“…Puhan et al described the 1-minute STS test as a stronger predictor of 2-year death; a higher number of movements was observed at baseline in those patients who would survive in comparison to non-survivors (19.5 versus 11.8 repetitions; AUC=0.78 of ROC curve) 38 . On the other hand, van Gestel et al, concluded that although the 1-minute STS was associated with objectively measured physical activity, it cannot be used to identify patients with an inactive lifestyle (AUC=0.31) 42 .Step test: A wide variety of protocols concerning the step test have been described in fifteen studies9,10,22,[44][45][46][47][48][49][50][51][52][53][54][55] . There is no standardization regarding cadence (self-paced or externally paced), step height, test duration and how the results should be presented 284(Table 1).…”

“…A step test can be performed with constant or incremental work rates. constant work rate, and patients were instructed to step up and down as many times as cutoff of 78 steps identified patients with an impaired exercise tolerance50 . Furthermore, the 6MST is reproducible 45 when performed by the same examiner, and showed to be The paced step test (PST) could also be considered a constant workload test because the stepping rate was kept constant throughout the test (15 steps/minute) until exhaustion.The difference is that the speed is externally paced and patients were instructed to…”

Supervised exercise protocol for lower limbs in subjects with chronic venous disease: an evaluator-blinded randomized clinical trial

“…The step test (ST) will be used to assess exercise capacity and will follow the recommendations previously published [30]. It will last 6 minutes (ST6), and the values of heart rate, systemic arterial pressure, dyspnea score by the modified BORG scale (0-10) and oxyhemoglobin saturation by a digital oximeter (SpO2%) will be registered at baseline and after the test.…”