Price David B, Bosnic-Anticevich Sinthia, Pavord Ian D, Roche Nicolas, Halpin David M G, Bjermer Leif, Usmani Omar S, Brusselle Guy, Ming Simon Wan Yau, Rastogi Sarang
1Observational and Pragmatic Research Institute, Singapore, Singapore.
2Academic Primary Care, Division of Applied Health Sciences, University of Aberdeen, Polwarth Building, Foresterhill, Aberdeen, AB25 2ZD UK.
Clin Transl Allergy. 2019 Aug 21;9:41. doi: 10.1186/s13601-019-0282-7. eCollection 2019.
Blood eosinophil count (BEC) and fractional exhaled nitric oxide (FeNO) concentration are established biomarkers in asthma, associated particularly with the risk of exacerbations. We evaluated the relationship of BEC and FeNO as complementary and independent biomarkers of severe asthma exacerbations.
This observational study included data from the Optimum Patient Care Research Database. Asthma patients (18-80 years) with valid continuous data for 1 year before FeNO reading, ≥ 1 inhaled corticosteroid prescription, and BEC recorded ≤ 5 years before FeNO reading were separated into cohorts. Categorisation 1 was based on the American Thoracic Society criteria for elevated FeNO concentration (high: ≥ 50 ppb; non-high: < 25 ppb) and BEC (high: ≥ 0.300 × 10 cells/L; non-high: < 0.300 × 10 cells/L). Categorisation 2 (FeNO concentration, high: ≥ 35 ppb; non-high: < 35 ppb) was based on prior research. Reference groups included patients with neither biomarker raised.
In categorisation 1, patients with either high FeNO or high BEC (n = 200) had a numerically greater exacerbation rate (unadjusted rate ratio, 1.31 [95% confidence interval: 0.97, 1.76]) compared with patients in the reference group. Combination of high FeNO and high BEC (n = 27) resulted in a significantly greater exacerbation rate (3.67 [1.49, 9.04]). Similarly, for categorisation 2, when both biomarkers were raised (n = 53), a significantly greater exacerbation rate was observed (1.72 [1.00, 2.93]).
The combination of high FeNO and high BEC was associated with significantly increased severe exacerbation rates in the year preceding FeNO reading, suggesting that combining FeNO and BEC measurements in primary care may identify asthma patients at risk of exacerbations.
血液嗜酸性粒细胞计数（BEC）和呼出一氧化氮分数（FeNO）浓度是哮喘已确立的生物标志物，尤其与病情加重风险相关。我们评估了BEC和FeNO作为重度哮喘加重的互补且独立生物标志物之间的关系。
这项观察性研究纳入了最佳患者护理研究数据库的数据。将在进行FeNO读数前1年有有效连续数据、≥1次吸入性糖皮质激素处方且在进行FeNO读数前≤5年记录了BEC的哮喘患者（18 - 80岁）分为不同队列。分类1基于美国胸科学会关于FeNO浓度升高（高：≥50 ppb；非高：<25 ppb）和BEC（高：≥0.300×10⁹细胞/L；非高：<0.300×10⁹细胞/L）的标准。分类2（FeNO浓度，高：≥35 ppb；非高：<35 ppb）基于先前的研究。参照组包括两种生物标志物均未升高的患者。
在分类1中，FeNO高或BEC高的患者（n = 200）与参照组患者相比，其病情加重率在数值上更高（未调整的率比，1.31 [95%置信区间：0.97, 1.76]）。FeNO高且BEC高的组合（n = 27）导致病情加重率显著更高（3.67 [1.49, 9.04]）。同样，对于分类2，当两种生物标志物均升高时（n = 53），观察到病情加重率显著更高（1.72 [1.00, 2.93]）。
FeNO高和BEC高的组合与FeNO读数前一年重度加重率显著增加相关，这表明在初级保健中结合FeNO和BEC测量可能识别出有加重风险的哮喘患者。
