Which field test should be used to compare the functional exercise capacities of patients with type 2 diabetes mellitus with and without diabetic peripheral neuropathy? Cross-sectional study.

ABSTRACT

BACKGROUND: The 6-minute step test (6MST) has begun to be used as a simple and effective alternative for assessing functional exercise capacity. There is no study using 6MSTs to evaluate the exercise capacities of patients with type 2 diabetes mellitus (DM) with and without diabetic peripheral neuropathy (DPN). OBJECTIVE: To compare the cardiorespiratory responses of the 6-minute walk test (MWT) and the 6MST exercise tests and to analyze the usability of the 6MST in Type 2 DM patients with and without neuropathy. METHODS: 32 non-neuropathic Type 2 DM, 32 neuropathic Type 2 DM patients, and 30 healthy volunteers were included in this cross-sectional study. Functional exercise capacity was evaluated with the 6MWT and the 6MST. The 30-second sit-stand test (30s STS) was used to evaluate general lower extremity muscle strength and function. RESULTS: There was a significant difference in the results of 6MWT (m), 6MST (number of steps), and 30s STS of the three groups (p<0.05). The 6MST results of patients with neuropathic Type 2 DM were significantly lower than those of non-neuropathic diabetics and those who were healthy (number of steps; 114.07±25.57 vs. 133.48±33.57 vs. 160.35±28.52, respectively) (p=0.001). The change in cardiorespiratory response in systolic blood pressure, heart rate, perceived dyspnea, and leg fatigue severity was significantly higher at 6MST than 6MWT in the three groups (p<0.05). 6MST was correlated with 6MWT (r=0.679, p=0.001), and 30s STS (r=0.589, p=0.001) in patients with Type 2 DM. CONCLUSIONS: Cardiorespiratory responses increased more in 6MST compared to 6MWT. In patients with Type 2DM, 6MWT and 6MST were moderately correlated with each other. 6MST is an effective and safe assessment method that may better reveal the differences in functional exercise capacity between neuropathic and non-neuropathic individuals in clinics.