Six-minute walk test in children with chronic conditions

Objectives The 6-minute walk test (6MWT) is a frequently used indicator of functional exercise capacity. The goals of this study were to compare the 6-minute walk performance of three paediatric patient groups with that of healthy peers, to assess differences between published reference values and to investigate which anthropometric characteristics best predict 6-minute walk performance. Methods 47 children with haemophilia (mean (SD) age 12.5 (2.9) years), 44 with juvenile idiopathic arthritis (JIA) (mean age 9.3 (2.2) years) and 22 with spina bifida (SB) (mean age 10.3 (3.1) years) were included. Subjects performed a 6MWT, and the distance walked (6MWD) was compared with published reference values. Results The haemophilia, JIA and SB patients achieved 90%-92%, 72%-75% and 60%-62% of predicted walking distances, respectively. There were significant associations between 6MWD and age, height and weight in the haemophilia group and 6MWD and height in the JIA group. None of the anthropometric variables was significantly related to 6MWD in the SB group. All anthropometric variables were strongly correlated with walking distance-body weight product (6Mwork) in all groups. Height explained 24% (haemophilia) and 11% (JIA) of the variance in 6MWD and 84% (haemophilia), 78% (JIA) and 73% (SB) of the variance in 6Mwork. Conclusions Walking distances of children with haemophilia, JIA and SB are significantly reduced compared with healthy references. Walking distance-body weight product seems to be a better outcome measure of the 6MWT compared with distance walked alone. Height is the best predictor of 6MWD and 6Mwork.