論文No1409
Airway calibre variation is a major determinant of exhaled nitric oxide's ability to capture asthma control
Alain Michils, Amaryllis Haccuria, Sebastien Michiels, Alain Van Muylem
European Respiratory Journal 2017 50: 1700392; DOI: 10.1183/13993003.00392-2017
＜背景＞
気道径の変化は呼気一酸化窒素(FENO)に影響を与える可能性があり、喘息コントロールにおいての支障になるかもしれない。
この研究では１秒量(FEV1)がFENOの喘息コントロールへの反映に影響するかを調べた。
＜方法＞
FENO、ACQ(喘息コントロール質問票）、FEV1を５２７名の患者の１８１９回の受診で最低２回測定した。
FENO-ACQの不一致の決定因子をロジスティック回帰分析で調べた。
FENOが喘息悪化や改善を２回の受診間で捉えることができたかは、層別化ＲＯＣ曲線で調べた。
＜結果＞
FEV1とFENO変化が同じ方向のときには、FENO-ACQの不一致は３倍に増幅した(P<0.001)。
FEV1とFENOが逆向きに動いたときのＡＵＣ値は0.765(95% CI 0.713–0.805) (改善時; p<0.001) and 0.769 (95% 0.706–0.810) (悪化時; p<0.001)であった。
FEV1とFENOが同じ向きに変化したときのＡＵＣ値は 0.590 (95% 0.531–0.653) (改善時; p=0.001) and 0.498 (95% 0.416–0.567) (悪化時; p=0.482)であった。
＜感想＞
喘息コントロールはFENOの変化で判断することも多いですが、FEV1の変化がFENOと同じ向きだとFENOの影響が薄まり、FEV1とFENOが逆向きだとFENOの影響が強まったようです。
Changes in airway calibre have the potential to modify exhaled nitric oxide fraction (FENO) values and could hamper how FENO captures changes in asthma control. Here, our objective was to assess whether forced expiratory volume in 1 s (FEV1) variations alter the ability of FENO to reflect asthma control.
FENO, asthma control (Asthma Control Questionnaire (ACQ)) and FEV1 were measured at least two times in 527 patients during 1819 pairs of visits. Determinants of FENO–ACQ discordance probability were evaluated through a logistic regression analysis. The effectiveness of FENO at capturing either asthma control worsening or improvement between two visits was then assessed by undertaking a stratified receiver operating characteristic curves analysis.
When FEV1 and FENO change in the same direction, the odds of FENO–ACQ being discordant are multiplied by 3 (p<0.001). The area under the curve values were 0.765 (95% CI 0.713–0.805) (improvement; p<0.001) and 0.769 (95% 0.706–0.810) (worsening; p<0.001) or 0.590 (95% 0.531–0.653) (improvement; p=0.001) and 0.498 (95% 0.416–0.567) (worsening; p=0.482) when FEV1 and FENO changed in the opposite or same direction, respectively.
The manner in which FENO and FEV1 vary concomitantly when asthma control changes determines the ability of FENO to capture this change: parallel or opposite changes in FEV1 and FENO either decrease or increase this ability to capture asthma control changes.