在一组未经选择的哮喘患者中，呼出气一氧化氮阈值与痰嗜酸性粒细胞计数≥3%相关。

Exhaled nitric oxide thresholds associated with a sputum eosinophil count ≥3% in a cohort of unselected patients with asthma.

机构信息

Department of Pulmonary Medicine, CHU Sart-Tilman, Liege, I GIGA Research Group, University of Liege, Belgium.

出版信息

Thorax. 2010 Dec;65(12):1039-44. doi: 10.1136/thx.2009.124925. Epub 2010 Jul 29.

DOI:10.1136/thx.2009.124925

PMID:20671307

Abstract

BACKGROUND

It has been claimed that exhaled nitric oxide (FeNO) could be regarded as a surrogate marker for sputum eosinophil count in patients with asthma. However, the FeNO threshold value that identifies a sputum eosinophil count ≥3% in an unselected population of patients with asthma has been poorly studied.

METHODS

This retrospective study was conducted in 295 patients with asthma aged 15–84 years recruited from the asthma clinic of University Hospital of Liege. Receiver-operating characteristic (ROC) curve and logistic regression analysis were used to assess the relationship between sputum eosinophil count and FeNO, taking into account covariates such as inhaled corticosteroids (ICS), smoking, atopy, age and sex.

RESULTS

Derived from the ROC curve, FeNO ≥41 ppb gave 65% sensitivity and 79% specificity (AUC=0.777, p=0.0001) for identifying a sputum eosinophil count ≥3%. Using logistic regression analysis, a threshold of 42 ppb was found to discriminate between eosinophilic and non-eosinophilic asthma (p<0.0001). Patients receiving high doses of ICS (≥1000 μg beclometasone) had a significantly lower FeNO threshold (27 ppb) than the rest of the group (48 ppb, p<0.05). Atopy also significantly altered the threshold (49 ppb for atopic vs 30 ppb for non-atopic patients, p<0.05) and there was a trend for a lower threshold in smokers (27 ppb) compared with non-smokers (46 ppb, p=0.066). Age and sex did not affect the relationship between FeNO and sputum eosinophilia. When combining all variables into the logistic model, FeNO (p<0.0001), high-dose ICS (p<0.05) and smoking (p<0.05) were independent predictors of sputum eosinophilia, while there was a trend for atopy (p=0.086).

CONCLUSION

FeNO is able to identify a sputum eosinophil count ≥3% with reasonable accuracy and thresholds which vary according to dose of ICS, smoking and atopy.

摘要

背景

有人声称，呼出气一氧化氮（FeNO）可以作为哮喘患者痰中嗜酸性粒细胞计数的替代标志物。然而，在未选择的哮喘患者人群中，能够识别痰中嗜酸性粒细胞计数≥3%的 FeNO 阈值尚未得到充分研究。

方法

这项回顾性研究在列日大学医院的哮喘诊所招募了 295 名年龄在 15-84 岁的哮喘患者，使用受试者工作特征（ROC）曲线和逻辑回归分析来评估痰中嗜酸性粒细胞计数与 FeNO 之间的关系，同时考虑了吸入性皮质类固醇（ICS）、吸烟、特应性、年龄和性别等协变量。

结果

从 ROC 曲线得出，FeNO≥41 ppb 对识别痰中嗜酸性粒细胞计数≥3%具有 65%的敏感性和 79%的特异性（AUC=0.777，p=0.0001）。使用逻辑回归分析发现，阈值为 42 ppb 可区分嗜酸性粒细胞性和非嗜酸性粒细胞性哮喘（p<0.0001）。接受高剂量 ICS（≥1000 μg 倍氯米松）治疗的患者 FeNO 阈值明显低于其他组（27 ppb 比 48 ppb，p<0.05）。特应性也显著改变了阈值（特应性患者为 49 ppb，非特应性患者为 30 ppb，p<0.05），吸烟者的阈值较低（27 ppb），而非吸烟者的阈值较高（46 ppb，p=0.066）。年龄和性别并不影响 FeNO 与痰嗜酸性粒细胞增多之间的关系。当将所有变量结合到逻辑模型中时，FeNO（p<0.0001）、高剂量 ICS（p<0.05）和吸烟（p<0.05）是痰嗜酸性粒细胞增多的独立预测因素，而特应性呈趋势（p=0.086）。