Physical activity level and performance in the six-minute walk test of children and adolescents with sickle cell anemia

Background: To establish determinants of maximum walking distance in the 6-minute walk test of children and adolescents with sickle cell anemia, and to compare the performance in this test with physical activity level between patients and healthy controls.

Methods: A cross-sectional study was performed in which the participants answered the Physical Activity Questionnaire for Older Children and Adolescents, and completed the 6-minute walk test.

Main results: Fifty-seven patients and 58 controls were studied. By univariate analysis of the patients, age (p<0.0001) and indirect bilirubin (p=0.008) were associated with maximum walking distance in the 6-minute walk test. In multivariate analysis, age was positively associated (p<0.0001; beta: 0.75), while body mass index was inversely associated with distance walked (p=0.047; beta: -0.32). This yields the following equation: maximum distance walked=487.7 (age×18.3)-(12×body mass index) meters. Patients reported a lower physical activity level however there was no significant difference in the distance walked in six minutes between patients (500.6±88.7m) and controls (536.3±94m).

Conclusion: The determinants for the 6-minute walk test in children and adolescents with sickle cell anemia were age and body mass index. There was no significant difference in the 6-minute walk test but patients with sickle cell anemia had a lower physical activity level compared to healthy controls.