Pulmonary Function Tests in Childhood Asthma: Which indices are Better for Assessment of Severity?

Abstract

To study pulmonary function tests in childhood asthma and to determine which indices are better for assessment of severity. This was a hospital-based, cross-sectional study. All consecutive children aged between 5 and 15 y with mild and severe persistent asthma were enrolled. Children in whom diagnosis of asthma was doubtful and those with chronic lung disease or suppurative lung disease were excluded. Diagnosis and classification was based on GINA guidelines. Age-/sex-matched controls who did not have history of wheezing any time in the past were selected. Detailed spirometry was performed on all children enrolled using RMS HELIOS 401. A total of 144 children were enrolled in the study (48 children in each group, i.e., control, mild and severe). Mean age of the study population was 9.06 ± 2.604 y with M:F ratio of 1.9:1. Mean percent of predicted values of FEV1, FVC, FEV1/FVC, FEF25-75, and PEFR in the control group was 94.83, 92.63, 103.25, 73.90, and 93.60; in the mild group was 90.58, 83.52, 111.10, 76.50, and 92.00; and in the severe group 57.56, 62.83, 92.85, 40.15, and 62.12, respectively. Values of all the indices decreased with increase in severity. FEV1 (95% CI: 0.884to0.971) having the highest correlation coefficient (-0.652) with respect to severity of asthma and FEV1/FVC having the least (-0.202). FEF25-75 (95% CI: 0.652 to 0.803) having a higher area under the curve, was a better spirometric parameter in predicting mild asthma. FEV1 was better index for assessing severity of asthma and FEF25-75 better in predicting mild asthma.