Reproducibility of the Six-Minute Walk Test in Children and Youth With Juvenile Idiopathic Arthritis

Objective: While the 6-minute walk test is increasingly being used in research to evaluate submaximal exercise capacity of children with juvenile idiopathic arthritis (JIA), psychometric properties with this population have not been well evaluated. We undertook this study to evaluate reproducibility (agreement and test–retest reliability) and to determine standard error of measurement (SEM) and smallest detectable difference (SDD) in children and youth with JIA. Methods: Participants (n = 22, mean ± SD age 13.1 ± 1.1 years, 63.6% female) completed a 6-minute walk test as part of their routine clinical assessment, and then repeated the 6-minute walk test at mean ± SD 8 ± 1.2 days later, in the same clinical setting with the same rater. Results: The intraclass correlation coefficient (95% confidence interval) was 0.86 (0.66–0.94); the SEM and SDD were 23.5 and 65.1 meters, respectively. Conclusion: These results provide evidence of good–excellent reproducibility of the 6-minute walk test with children and youth with JIA and support the use of the 6-minute walk test as a measure of submaximal exercise capacity in clinical practice and research.