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M.J. Oliveros1, P. Serón1, G. Marzuca1, C. Roman2, M. Galvez2, R. Navarro3, G. Latín4, T. Marileo5, J.P. Molina6, P. Sepúlveda1, S. Muñoz7
1Universidad de La Frontera, Medicina Interna, Facultad de Medicina, Temuco, Chile, 2Complejo Hospitalario San José, Santiago, Chile, 3Hospital Clínico Universidad de Chile, Santiago, Chile, 4Hospital San Borja Arriarán, Santiago, Chile, 5Hospital Regional de Antofagasta, Antofagasta, Chile, 6Hospital San Juan de Dios, Santiago, Chile, 7Universidad de La Frontera, Salud Pública, Facultad de Medicina, Temuco, Chile
Background: The Six-minute walk test (6MWT) is useful, simple and safe to assess functional capacity in different populations. The two-minute step test (2MST) was initially presented as an alternative to the 6MWT based on the association between the two tests in older adults, however some authors propose that it should not be a substitute but rather a complement in the fitness evaluation. Specifically in coronary disease, despite the potential and clinical utility of 2MST, the relationship of both tests in this population is unknown.
Purpose: To determine the relationship between 6MWT and 2MST, secondarily to explore the relationship of bio-demographic factors for both tests in subjects with treated cardiovascular disease.
Methods: 6MWT and 2MST were applied to subjects with coronary disease treated in 6 hospitals in Chile, between May 2019 and February 2020 in the context of the study randomized, multi-center, non-inferiority clinical trial conducted (Hybrid Cardiac Rehabilitation Trial, HYCARET). Additionally, lower limb strength (LFL) assessed by chair stand test, grip strength assessed by dynamometer, and physical measurements were applied. The correlation coefficient and its p-values was estimated to 6MWT and 2MST. The relationships between the both test and age, weight, height, and strength were analysed by correlation analysis. Finally, we explored the variability in both test attributable to bio-demographic variables using regression models.
Results: 163 participants performed both tests (average age = 58.7 years; 23.3% female; 67.5% revascularized by angioplasty; 31.3% revascularized by surgery). There is a weak positive correlation between 6MWT and 2MST in subjects with treated coronary disease (r=0.28, p=0.0003). Heart rate (MD 5.6 lpm) and diastolic blood pressure (MD 2.1 mm Hg) were higher at the end of 6MWT than 2MST. While age (r = -0.27), weight (r= 0.25), height (r= 0.49), LFL (r= 0.41) and grip strength (r= 0.53) correlate weakly or moderately to covered distance in 6MWT, the number of steps by 2MST correlates only weakly to height (r= 0.23), LFL (r= 0.34) and grip strength (r= 0.34). Age, weight, height, LFL and grip strength would explain better the meters walked in the 6MWT than the steps achieved in the 2MST.
Conclusion(s): In subjects with treated coronary disease, the distance walked in the 6MWT and the steps performed in the 2MST are weakly correlated. Both tests correlate differently to age, weight, height and muscle strength.
Implications: In subjects with treated coronary disease, it does not seem advisable to replace 6MWT with 2MST when it is possible to do so. Additionally, 2MST may provide additional information in the fitness evaluation. The usefulness of 2MST in this population needs to be further studied.
Funding, acknowledgements: Fondecyt Grant N° 1181734, financed by the National Agency for Research and Development (ANID), Chile.
Keywords: Fitness evaluation, Cardiac Rehabilitation
Topic: Cardiorespiratory
Did this work require ethics approval? Yes
Institution: Universidad de La Frontera
Committee: Comité Ético Científico de la Universidad de La Frontera
Ethics number: Acta N° 032_18
All authors, affiliations and abstracts have been published as submitted.
