Reference Values for the Six Minute Walk Test in Children with Juvenile Idiopathic Arthritis

Aims: To (1) describe six-minute walk test (6MWT) reference values for children with Juvenile Idiopathic Arthritis (JIA) and (2) explore predictors of 6MWT distance. A secondary objective was to determine how 6MWT distances of children with JIA compare to those of children without JIA reported in the literature. Methods: Demographic, clinical, height, weight and 6MWT data were extracted from clinical records of 120 children with JIA (70.8% female, mean age=12.4 +/- 3.2 years) who attended a follow-up rheumatology clinic. A total of 272 6MWTs were included in the analyses. Linear mixed effects modeling was used to determine the relationship between predictive variables and 6MWT distance. 6MWT distances were compared to predicted values using published equations for estimating 6MWT distances in children without JIA. Results: Height, weight, and age were predictive of 6MWT distance (R-2 = 0.62). Mean 6MWT distances for children with JIA were lower than those reported for children without JIA (p < 0.001). Mean 6MWT distance was 84% and 78% of predicted values for children without JIA. Conclusion: The reference values and associated predictive model have application for assessing exercise capacity in children with JIA.