Control of asthma and its correlation to non-specific bronchial hyperreactivity in young patients

Abstract

One of the most important purposes of treatment of asthma is achievement and maintenance of control of the disease. The present study investigated relationship between a level of asthma control and bronchial hyperreactivity (BHR). This study involved 145 outpatients aged 18 to 34 yrs. The control of asthma was evaluated using the Asthma Control Test (ACT). The ACT score of 25 indicated the full control of asthma, the scores between 20 and 24 indicated the good control and the scores < 20 suggested the poor control. BHR was assessed in the methacholine challenge test; PD20  was the dose of methacholine causing 20 % fall in FEV₁. PD 20 ≤ 0.046 mg suggested high BHR, PD 20 ranged 0.047 mg to 0.228 mg indicated moderate BHR, and PD 20 of 0.229–0.471 mg corresponded to low BHR. Asthma was fully controlled in 17 mild asthma patients (22 %) and was poorly controlled in 13 of them (17 %). No-one of moderate and severe asthma patients had the full control of the disease. Good control of moderate and severe asthma was found in 22 (50 %) and 2 (8 %) respectively, poor control was estimated in 22 (50 %) and 23 (92 %) patients respectively. The mean methacholine concentrations in mild, moderate and severe asthma groups were 0.304 ± 0.011 mg, 0.211 ± 0.019 mg and 0.101 ± 0.015 mg respectively (p = 0.03). BHR was low in all patients with fully controlled asthma with no regards to its severity. The patients with well controlled asthma had predominantly low and moderate BHR, and 9 % of them had high BHR. BHR was also high in 57 % of the patients with poorly controlled asthma. There was a close correlation between the ACT score and PD20 of methacholine (r = 0.78; р < 0.001). In conclusion, the results revealed insufficient quality of outpatient treatment of asthma, particularly of moderate and severe asthma. ACT is reasonable to be used in wide clinical practice, especially in primary care settings.