TY - JOUR T1 - Correlation of Spirometry and Symptom Scores in Childhood Asthma and the Usefulness of Curvature Assessment in Expiratory Flow-Volume Curves JF - Respiratory Care SP - 1744 LP - 1752 VL - 52 IS - 12 AU - Johannes H Wildhaber AU - Josué Sznitman AU - Paul Harpes AU - Daniel Straub AU - Alexander Möller AU - Pavel Basek AU - Felix H Sennhauser Y1 - 2007/12/01 UR - http://rc.rcjournal.com/content/52/12/1744.abstract N2 - BACKGROUND: Spirometry, and in particular forced expiratory volume in the first second (FEV1), are standard tools for objective evaluation of asthma. However, FEV1 does not correlate with symptom scores, and hence its value in the assessment of childhood asthma may be limited. Therefore, some clinicians subjectively assess the presence of curvature in the maximum expiratory flow-volume (MEFV) curves obtained from spirometry, where concave patterns are observable despite normal FEV1 values. OBJECTIVE: To evaluate the usefulness of subjective and objective measures of the curvature in the descending phase of the MEFV curve for the assessment of asthma. METHODS: We obtained symptom scores and performed spirometry in 48 patients with asthma (21 females, mean ± SD age 10.8 ± 2.4 y). We measured FEV1, the ratio of FEV1 to forced vital capacity (FEV1/FVC), maximum expiratory flow at one quarter of the way, and at halfway, through the forced expiratory maneuver (MEF25 and MEF50, respectively), and maximum expiratory flow in the middle half of the forced expiratory maneuver (MEF25–75). Expiratory obstruction was ranked independently by 3 pediatric pulmonologists, by subjective assessment of the MEFV curve. In addition, the curvature of the descending limb of the MEFV curve was quantitatively estimated by introducing an “verage curvature index.” RESULTS: No significant correlations were found between FEV1, MEF50, MEF25, and MEF25–75, respectively, and symptom score (r = −0.22, p = 0.14; r = −0.23, p = 0.11; r = −0.28, p = 0.057; r = −0.27, p = 0.06). A weak correlation was found for FEV1/FVC and symptom score (r = −0.33, p = 0.021). However, quantitatively determined average curvature index (ACI) correlated significantly better with measured symptom scores (r = 0.53, p < 0.001) and were in good agreement with the assessment of expiratory obstruction from subjective curvature assessment. CONCLUSIONS: Our general findings show that individual lung function variables do not correlate well with symptoms, whereas subjective curvature assessment is thought to be helpful. With the average curvature index we have illustrated a potential clinical usefulness of quantifying the curvatures of MEFV curves. ER -