Glucocorticosteroid is known to be the most effective anti-inflammatory agent at present for asthma treatment. However, some asthmatics are insensitive or resistant to steroid. The purpose of this study was to examine the sensitivity to the conventional short course of steroid burst in asthma. Ninety-two consecutive patients with moderate to severe asthma were classified as steroid-sensitive asthma (SSA) or steroid insensitive asthma (SIA) according to their presence or absence of improvement in morning forced expiratory volume in one second (FEV1) by ? 15% after asthma treatment with drugs including prednisolone 30mg/day for 7 days. Fifty-six (60.9%) patients had SIA. The SIA patients had a significantly higher age (p<0.01), a trend of longer duration of asthma (p=0.06), more severe asthma (p<0.01), and a more frequent association with other thoracic diseases including emphysema (p?0.01) than the SSA patients. However, there were no significant differences between SIA and SSA in sex, smoking, family history of atopy, and total serum IgE levels. The degree of improvement in FEV1 following a short course of steroid burst was significantly related to metacholine airway hyper responsiveness (r=0.366, p?0.01), and to peripheral blood eosinophil counts (r=0.235,p?0.01) in all patients.
In conclusion, these results showed that about half of patients with moderate to severe asthma were insensitive to the conventional short course of steroid burst, and that the steroid sensitivity was dependent on asthma severity and might also be related to irreversible airflow limitation resulting from long-standing asthma.
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