Risk Factors Associated with Persistent Airflow Limitation in Patients with Severe Asthma

Background and Asthma is a widespread chronic inflammatory disease of the airways that may become uncontrollable in severe subtypes, even with radical treatments. The present study attempts to determine the risk factors of the irreversible airway obstruction in severe asthma patients. The study population were 72 patients with severe asthma, aged 16- 75 year old. Spirometry was performed and after receiving Salbutamol the subjects were divided into two groups (n= 36 per group). Group I included patients with severe reversible asthma and group II had severe irreversible asthma. Clinical risk factors were considered including age of the first onset of asthma, smoking, BMI, aspirin allergy, taking corticosteroids, and history of animals contact. Moreover, the level of total serum IgE, and the percentage of eosinophils in peripheral blood smear and sputum were investigated. Afterwards, a comparison was made between the two groups. Adult-onset rate was significantly higher in patients with irreversible asthma (P=0.34). Smoking rate (P= 0.003), serum IgE levels (P =0.003), percentage of sputum eosinophil (P =0.003) were significantly higher among patients with irreversible asthma. There was no significant difference between the two groups in the use of corticosteroids, BMI, aspirin sensitivity, history of contacts with animals, and peripheral blood eosinophil levels. Smoking is a great risk factor and its quitting is of great benefit for patients with asthma. Serum IgE and sputum eosinophil levels may be considered as co-factors in patients with irreversible asthma.