Li Albert M, Tsang Tony W T, Lam Hugh S, Sung Rita Y T, Chang Anne B
Department of Paediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
Respirology. 2008 May;13(3):400-7. doi: 10.1111/j.1440-1843.2007.01222.x.
Studies of Western populations have shown that increased exhaled nitric oxide (FeNO) and/or sputum eosinophils (sp-Eos) are predictive of asthma exacerbations. However, the utility of these measurements in different populations and settings is unknown. This study aimed to determine the predictors for failure of reduction of inhaled corticosteroid (ICS) doses in children with stable asthma.
Fifty children (median age 11.8 years, interquartile range (IQR) 5.9 years) had their dose of ICS halved every 8 weeks until they reached the study end-point (exacerbation or weaned off ICS). Spirometry, FeNO and induced sputum cells were measured at baseline and at each stage of ICS reduction.
Eleven subjects suffered an asthma exacerbation and the remainder was successfully weaned off ICS. Subjects with an exacerbation were older (15.4 years (IQR 5.4) vs 11.4 years (IQR 3.9), P = 0.019) and more likely to be boys (P = 0.035). FeNO (median 156 p.p.b. (IQR 131) vs 76.1 p.p.b. (IQR 79.5), P = 0.013) and sp-Eos (17.3% (IQR 33.8%) vs 7.1% (IQR 9.9%), P = 0.019) were significantly greater in those who had an exacerbation. The areas under the receiver operating characteristic curves for FeNO (0.78, 95% CI: 0.59-0.97, P = 0.013) and sp-Eos (0.76, 95% CI: 0.56-0.96, P = 0.016) were similar (P = 0.88) and both were significantly greater than that for FEV(1)% predicted (0.12, 95% CI: 0.08-0.56, P = 0.0013).
Older boys with raised FeNO and sp-Eos are at higher risk of failure of reduction in their ICS dose. Monitoring airway inflammation in children with asthma using FeNO or sp-Eos is clinically useful in guiding ICS dose reduction in a non-Western outpatient setting.
针对西方人群的研究表明，呼出一氧化氮（FeNO）增加和/或痰液嗜酸性粒细胞（sp-Eos）增多可预测哮喘发作。然而，这些测量指标在不同人群和环境中的效用尚不清楚。本研究旨在确定稳定期哮喘儿童吸入性糖皮质激素（ICS）剂量降低失败的预测因素。
五十名儿童（中位年龄11.8岁，四分位间距（IQR）5.9岁）每8周将ICS剂量减半，直至达到研究终点（发作或停用ICS）。在基线以及ICS剂量降低的每个阶段测量肺功能、FeNO和诱导痰液细胞。
11名受试者哮喘发作，其余受试者成功停用ICS。发作的受试者年龄较大（15.4岁（IQR 5.4）对11.4岁（IQR 3.9），P = 0.019）且更可能为男孩（P = 0.035）。发作的受试者FeNO（中位值156 ppb（IQR 131）对76.1 ppb（IQR 79.5），P = 0.013）和sp-Eos（17.3%（IQR 33.8%）对7.1%（IQR 9.9%），P = 0.019）显著更高。FeNO（0.78，95%CI：0.59 - 0.97，P = 0.013）和sp-Eos（0.76，95%CI：0.56 - 0.96，P = 0.016）的受试者工作特征曲线下面积相似（P = 0.88），且均显著大于预测的FEV(1)%的曲线下面积（0.12，95%CI：0.08 - 0.56，P = 0.0013）。
FeNO和sp-Eos升高的年长男孩降低ICS剂量失败的风险更高。在非西方门诊环境中，使用FeNO或sp-Eos监测哮喘儿童的气道炎症对指导ICS剂量降低具有临床意义。
