An Equation With Clinical Applicability and Adequate Validity to Predict the Maximum Oxygen Consumption of Individuals Post-stroke.

ABSTRACT

OBJECTIVE: To develop an equation with clinical applicability and adequate validity to predict the maximum oxygen consumption (V̇o2max) of individuals post-stroke. DESIGN: A cross-sectional study. SETTING: A university laboratory. PARTICIPANTS: Individuals post-stroke in the chronic phase (at least 6 months post-stroke). Step-1 (equation development) n=50, aged 55±12 years; Step-2 (validity investigation) n=20, aged 58±8 years (N=50 [step 1], N=20 [step 2]). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE(S) Step-1 (equation development) multiple linear regression analysis was performed. DEPENDENT VARIABLE V̇o2max (mL/kg/min) in the cardiopulmonary exercise test. INDEPENDENT VARIABLES age (years), sex (1-women, 2-men), body mass index (BMI) (kg/m2), and distance (meters) in the Six-Minute Walk Test (6MWT) (6MWT-Equation) or in the Incremental Shuttle Walk Test (ISWT) (ISWT-Equation). Step-2 (validity investigation) agreement between the V̇o2max measured and predicted was evaluated with the intraclass correlation coefficient (ICC) with 95% confidence interval (CI) and the Bland-Altman method (α=5%). RESULTS: In step-1 (equation development), the 4 independent variables for each equation were retained (6MWT-Equation R2=0.68, P<.001; ISWT-Equation R2=0.58, P<.001). In step-2 (validity investigation), the 6MWT-Equation showed an ICC of 0.73 (95% CI=0.30, 0.89; P=.004) and a mean bias of 0.003 mL/kg/min; and the ISWT-Equation showed an imprecise ICC of 0.55 (95% CI=-0.12, 0.82; P=.045) and a mean bias of 0.971 mL/kg/min. 6MWT-Equation (V̇o2max=22.239+0.02 × distance in the 6MWT+4.039 × sex-0.157 × age-0.265 × BMI) showed adequate validity. CONCLUSIONS: An equation with clinical applicability and adequate validity in the investigated sample was developed to predict the V̇o2max of individuals post-stroke in the chronic phase (6MWT-Equation). Future studies with larger sample should investigate its external validity.