Can functional walk tests add value to the prediction of cardiorespiratory fitness after stroke? A prospective cohort study

Mari Gunnes; Inger-Lise Aamot Aksetøy; Turid Follestad; Bent Indredavik; Torunn Askim

doi:10.1371/journal.pone.0255308

Can functional walk tests add value to the prediction of cardiorespiratory fitness after stroke? A prospective cohort study

PLoS One. 2021 Aug 2;16(8):e0255308. doi: 10.1371/journal.pone.0255308. eCollection 2021.

Authors

Mari Gunnes^{1

2}, Inger-Lise Aamot Aksetøy³, Turid Follestad⁴, Bent Indredavik^{1

2}, Torunn Askim^{1

2}

Affiliations

¹ Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.
² Stroke Unit, Department of Internal Medicine, St. Olav's University Hospital, Trondheim, Norway.
³ Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.
⁴ Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.

Abstract

Background: Cardiorespiratory fitness is often impaired following stroke, and peak oxygen consumption (VO2peak) is an important prognostic value of all-cause mortality. The primary objective was to investigate whether functional walk tests assessed in the subacute phase after stroke added value in predicting VO2peak in chronic stroke, in addition to age, sex and functional dependency. Secondary objectives were to investigate associations between daily physical activity and functional walk tests, and with VO2peak in chronic stroke.

Methods: This prospective cohort study included eligible participants originally included in the randomized controlled trial Life After Stroke. Functional walk tests, i.e., six-minute walk test (6MWT) and maximal gait speed, were assessed at inclusion and 18 months later. VO2peak [ml/kg/min] was assessed by a cardiopulmonary exercise test on a treadmill 20 months after inclusion. Daily physical activity was measured by a uniaxial accelerometer (activPAL) at 18-month follow-up.

Results: Ninety-two community-dwelling individuals, with a mean (SD) age of 69.2 (10.6) years and 33 (35.9%) women, were included 3 months after stroke onset. Eighty-three (90.2%) participants had a modified Rankin Scale (mRS) score of 1 or 2, indicating functional independence. An overall assessment of four prediction models indicated the combination of age, sex, mRS and 6MWT as predictors to be the best fitted model in predicting VO2peak (adjusted R2 = 0.612). Secondary results showed statistically significant, but not clinically significant, associations between daily physical activity and functional walk tests, and with VO2peak.

Conclusions: 6MWT add significant value to the prediction of mean VO2peak in the chronic phase in mild strokes, in combination with age, sex and functional dependency. This prediction model may facilitate clinical decisions and rehabilitation strategies for mildly affected stroke survivors in risk of low levels of VO2peak. Future studies should validate the model in various stages after stroke and in patients moderately and severely affected.

MeSH terms

Aged
Cardiorespiratory Fitness* / physiology
Exercise Test / methods
Female
Humans
Male
Middle Aged
Oxygen Consumption*
Prognosis
Prospective Studies
Stroke Rehabilitation
Stroke* / physiopathology
Walk Test* / methods

Grants and funding

The financial support for this study was granted as a doctoral scholarship from The Norwegian Fund for Postgraduate Training in Physiotherapy, in addition to the Liaison Committee for education, research and innovation in Central Norway (TA). Life After Stroke (LAST), the original study on which the present article is based, was funded by the Research Council of Norway (grant no 205309/H10) (BI). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.