Objective: To evaluate the accuracy of the modified Borg scale to estimate lung impairment, measured via FEV(1) in children and adolescents with cystic fibrosis.
Methods: This cross-sectional prospective study was conducted with cystic fibrosis patients, 6-18 y old. With the modified Borg scale we evaluated their subjective perceptions of dyspnea before and after submaximal exercises, and its correlation with lung function (spirometry), 6-min walk test (6MWT), and nutritional status according to body mass index.
Results: Forty-one patients (mean +/- SD age range 11.1 +/- 4.1 y), were included in the study. The median (and interquartile range) modified Borg scale score after 6MWT was 2 (1-3). The mean percent-of-predicted FEV(1) (FEV(1)%) was 97 +/- 32%. The Z score of the 6MWT distance (6MWTZ) for 61% of the patients was < or = -2. The modified Borg scale correlated weakly with the other variables when all patients in the sample were analyzed. There was a significantly greater correlation of the Borg-scale score with FEV(1)% (r = -0.59, P = .003) and with 6MWTZ (r = 0.46, P = .03) when patients older than 9 years were evaluated separately. The receiver operating characteristic curve analysis revealed that a modified-Borg-scale cut-off point of 2.5 generated an area of 0.80, a sensitivity of 80%, a specificity of 77%, and an accuracy of 0.78 to predict FEV(1)% lower than 80% in the group of patients older than 9 years.
Conclusions: The modified Borg scale is accurate to assess the subjective perception of dyspnea of children older than 9 years and adolescents with cystic fibrosis.