Application of the Six-Minute Walk Test in Assessment of the Cardiopulmonary Function of Children With Idiopathic Scoliosis

Abstract

Study Design. A retrospective observational study. Obsjective. To assess whether the 6-minute walk test (6MWT) can predict cardiopulmonary function in children with idiopathic scoliosis (IS) as an alternative to the cardiopulmonary exercise test (CPET). Summary of Background Data. Cardiopulmonary functional impairment in the setting of IS is a common health problem. A simple and convenient assessment method is needed. Methods. We recruited 65 children (eight male, 57 female) aged 10.70–14.84 years old with IS. Radiographic characteristics of the cohort were measured, including Risser’s sign and Cobb angle. We measured cardiopulmonary exercise tolerance using both the 6MWT and CPET and their corresponding indicators, including six-minute walking distance (6MWD) and peak oxygen uptake (peak VO2), respectively. Pearson correlation analysis was used to determine the relationship between 6MWT indicators and IS parameters. Linear regression models were used to explore the relationship between 6MWT and CPET response indicators. Results. Over a third of the cohort (35.4%) had a Risser’s sign grade of 0, with 21.5% in grade 2 and 3, respectively. The cohort’s mean Cobb angle was 26.02 degrees. 6MWD was significantly positively correlated with Risser’s sign (R=0.258; P=0.038) and change in respiratory rate (△RR) positively correlated with vertebral rotation (R=0.264; P=0.034). 6MWD positively correlated with peak VO2, peak VO2/heart rate (HR) and metabolic equivalents (METs), and negatively correlated with ventilation equivalent of carbon dioxide slope (VE/VCO2 slope) (P<0.05). These four CPET indicators were found to be predicted from 6MWD in the linear regression model (P<0.05). Conclusion. CPET response indicators, especially peak VO2, can be predicted using 6MWD among other factors. The 6MWT can therefore be used to rapidly and efficiently predict the cardiorespiratory tolerance of children with IS. Level of Evidence. 3