論文No2832
Ratio of FEV1/Slow Vital Capacity of < 0.7 Is Associated With Clinical, Functional, and Radiologic Features of Obstructive Lung Disease in Smokers With Preserved Lung Function
Spyridon Fortis,Alejandro P. Comellas,Surya P. Bhatt,...David Couper,Donald Tashkin,Igor Barjaktarevic
CHEST, VOLUME 160, ISSUE 1, P94-103, JULY 01, 2021
＜背景＞
軽度の呼気気流制限は通常のFEV1/FVC比にもとづくスパイロメトリの基準では認識できないかもしれない。
＜目的＞
強制肺活量(FVC)の代わりにslow肺活量(SVC)を使用することで
早期あるいは軽度の閉塞性肺疾患患者のスパイロメトリによる同定の感度が上がるかを検討する。
＜方法＞
the Subpopulations and Intermediate Outcome Measures in COPD Studyコホートで
登録時の気管支拡張薬吸入後のFEV1/FVC≥ 70%およびFEV1%≥ 80%の854名の現喫煙者および既喫煙者を対象とした。
ベースラインの特徴、胸部ＣＴスキャンの特徴、増悪、
COPD（気管支拡張薬吸入後のFEV1/FVC <0.7)への進行を、
気管支拡張薬吸入後のFEV1/SVC ≥ 70%の734名およびFEV1/SVC <0.7の120名のフォローアップ期間で比較した。
多変量線形およびロジスティック回帰モデル、負の二項モデル、間隔打ち切り比例ハザード回帰モデルで、
臨床背景、喫煙状態で補正後にFEV1/SVC<0.7とこれらのアウトカムとの関連を検討した。
＜結果＞
FEV1/SVC <0.7の参加者はFEV1/SVC≥ 0.7の参加者よりも高齢で、FEV1が低く、肺気腫が多かった。
補正後解析で、FEV1/SVC <0.7の群は肺気腫の率が0.45% (95% CI, 0.09%-0.82%)、
ガストラッピングの率が2.52%(95% CI, 0.59%-4.44%)、
parametric response mappingによる機能的細気道のパーセントが2.78%(95% CI, 0.72%-4.83%) 、
ベースラインでFEV1/SVC≥ 0.7群よりも多かった。
フォローアップ中央値1500日で、FEV1/SVC <0.7群は増悪と関連していなかった(incident rate ratio [IRR], 1.61; 95% CI, 0.97-2.64)。
しかし、重症の増悪とは関連していた (IRR, 2.60; 95% CI, 1.04-4.89)。
FEV1/SVC <0.7群は臨床背景、喫煙で補正後に3年フォローアップ後に
COPDへの進展と関連していた(hazard ratio, 3.93; 95% CI, 2.71-5.72)。
気管支拡張薬吸入前のFEV1/SVC <0.7あるいはFEV1/SVC <lower limit of normalと
胸部ＣＴ、COPDとの関連でも同様の結果であった。
＜感想＞
喫煙歴があり、FEV1/FVCが正常でもFEV1/SVCが70%未満の群では、将来のCOPDへの進行、重症増悪のリスクがあったようです。
Background
Mild expiratory flow limitation may not be recognized using traditional spirometric criteria based on the ratio of FEV1/FVC.≥ 0.7
Research Question
Does slow vital capacity (SVC) instead of FVC increase the sensitivity of spirometry to identify patients with early or mild obstructive lung disease?
Study Design and Methods
We included 854 current and former smokers from the Subpopulations and Intermediate Outcome Measures in COPD Study cohort with a postbronchodilator FEV1/FVC ≥ 0.7 and FEV1 % predicted of ≥ 80% at enrollment. We compared baseline characteristics, chest CT scan features, exacerbations, and progression to COPD (postbronchodilator FEV1/FVC, < 0.7) during the follow-up period between 734 participants with postbronchodilator FEV1/SVC of ≥ 0.7 and 120 with postbronchodilator FEV1/SVC < 0.7 at the enrollment. We performed multivariate linear and logistic regression models and negative binomial and interval-censored proportion hazards regression models adjusted for demographics and smoking exposure to examine the association of FEV1/SVC < 0.7 with those characteristics and outcomes.
Results
Participants with FEV1/SVC < 0.7 were older and had lower FEV1 and more emphysema than those with FEV1/SVC ≥ 0.7. In adjusted analysis, individuals with postbronchodilator FEV1/SVC < 0.7 showed a greater percentage of emphysema by 0.45% (95% CI, 0.09%-0.82%), percentage of gas trapping by 2.52% (95% CI, 0.59%-4.44%), and percentage of functional small airways disease based on parametric response mapping by 2.78% (95% CI, 0.72%-4.83%) at baseline than those with FEV1/SVC ≥ 0.7. During a median follow-up time of 1,500 days, an FEV1/SVC < 0.7 was not associated with total exacerbations (incident rate ratio [IRR], 1.61; 95% CI, 0.97-2.64), but was associated with severe exacerbations (IRR, 2.60; 95% CI, 1.04-4.89). An FEV1/SVC < 0.7 was associated with progression to COPD during a 3-year follow-up even after adjustment for demographics and smoking exposure (hazard ratio, 3.93; 95% CI, 2.71-5.72). We found similar results when we examined the association of prebronchodilator FEV1/SVC < 0.7 or FEV1/SVC less than the lower limit of normal with chest CT scan features and progression to COPD.
Interpretation
Low FEV1 to SVC in current and former smokers with normal spirometry results can identify individuals with CT scan features of COPD who are at risk for severe exacerbations and is associated with progression to COPD in the future.
Trial Registry
ClinicalTrials.gov; No.: NCT01969344T4; URL: www.clinicaltrials.gov
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