Avaliação da capacidade cardiorrespiratória e validação do incremental shuttle walk test em indivíduos com Diabetes Mellitus Tipo 2

Abstract

Introduction: Type 2 Diabetes Mellitus (DM2) is characterized by hyperglycemia and resistance to the insulin action. It leads to a reduction in cardiorespiratory capacity. Although the gold standard for assessing cardiorespiratory capacity is VO2 peak using the cardiopulmonary exercise test (CPET), valid instruments that are simpler, more accessible to the general population, which reflect daily activities and responses to submaximal efforts are needed. The measurement properties of the Incremental Shuttle Walk Test (ISWT) have not yet been tested in individuals with DM2. Objective: To test the validity and reliability of the ISWT in individuals with DM2. Methods: Cross-sectional, methodological, and multicenter study. Individuals with DM2, aged >18 years, of both sexes, were included. The ISWT and the six-minute walk test (6MWT) were performed for construct validation (distance walked) and reliability (test and retest). For criterion validation, maximum CPET was performed to obtain oxygen consumption at peak effort (VO2 peak). The Pearson correlation coefficient was used to analyze the correlations between the distance covered in the ISWT, VO2 peak and distance in the 6MWT, the intraclass correlation coefficient was used to analyze reliability and the paired t-test was used to compare responses to the 6MWT and ISWT. Results: 50 participants were included, 50% female, 57±11 years old. The correlation between the distances covered in the ISWT and 6MWT was high (r=0.62; p<0.001). The test-retest reliability of the ISWT was very high (ICC=0.86; p<0.001). The correlation between peak VO2 and the distance covered in the ISWT was low (r=0.13; p=0.605). The distance covered in the 6MWT was greater compared to the ISWT (6MWT=560±83; ISWT=446±144m; p<0.05), as well as the peak heart rate (6MWT=118±17; ISWT=125±21bpm; p<0.05), the double-product (6MWT=16710.80±3664.43; ISWT=17742.82±4958.50mmHg.bpm; p<0.05), and the subjective perception of exertion (6MWT= 3±2; ISWT=4±2; p<0.05) at the end of the test were higher in the ISWT compared to the 6MWT. Conclusion: The ISWT is valid and reliable for assessing cardiorespiratory capacity in DM2 and imposes greater hemodynamic stress than the 6MWT in individuals with DM2.