Relationship Between Asthma Control Score and Small AIrway Dysfunction in Patients With Bronchial Asthma

Objective: To determine the correlation between asthma control score and small airway dysfunction. Patients and methods: Patients presenting to the OPD of Pulmonology with a diagnosis of asthma were enrolled in the study. Their asthma control was assessed via a validated scale rating from 5-25 (Asthma control test) and their spirometry was performed. Mid-expiratory flow (FEF25-75%) was taken to measure small airway dysfunction. All the spirometric parameters including FEV1, FVC, FEV1/FVC, PEFR, and FEF25-75% were obtained. The data was analyzed via SPSS 22. Pearson’s correlation between ACT score and FEF25-75% was calculated. A p-value of <0.05 was taken as significant. Results: A total of 78 adult patients were enrolled of which 42.3% were males. The Mean age of them was 46.79 (±17.7), BMI 26.86 (± 7.2), and FEV1 was 53.1% predicted (± 20.7). Five percent of patients had normal FEV/FVC but low FEF25-75%. The Pearson’s correlation between ACT score and FEF25-75% was 0.289 (p=008). After linear regression analysis, an R2 of 0.11 was obtained. Conclusion: We found a statistically significant but weak correlation between asthma control score and small airway dysfunction. FEF25-75% may be of value in the diagnosis of asthma when the patient has symptoms and conventional spirometry is normal.