TY - JOUR

T1 - Exhaled nitric oxide measure using multiple flows in clinically relevant subgroups of COPD

AU - Roberts, Nassim Bazeghi

AU - Gerds, Thomas A

AU - Budtz-Jørgensen, Esben

AU - Hove, Jens

AU - Vestbo, Jørgen

N1 - Copyright © 2011 Elsevier Ltd. All rights reserved.

PY - 2011

Y1 - 2011

N2 - Although there is widespread interest in fractional exhaled nitric oxide (FeNO) as a non-invasive, time and cost effective biomarker for assessing airway inflammation in chronic obstructive pulmonary disease (COPD), its usefulness is still controversial. We examined the FeNO levels in clinically meaningful subgroups of COPD in a group of 91 COPD patients with FEV(1) 17-77% of predicted. Multiple flow rates FeNO at 10, 30, 50, 100 and 200 mL/s were measured and a two-compartment model was used to estimate the diffusion Capacity (D), alveolar NO concentration (Calv) and airway wall NO concentration (Caw). All patients had spirometry, assessment of symptoms with questionnaires and low-dose CT scan as well as assessment of weight and body composition. We examined the following subgroups of COPD: Patients with 1) Severe emphysema, 2) Chronic bronchitis, 3) Frequent exacerbations, 4) Loss of lean body mass and 5) Low fat-free mass index. We used advanced non-linear mixed model adjusted for age and gender. The modelled differences in D, Calv or Caw among COPD subgroups were small and not statistically significant. The analysis showed significant effects of current smoking on Caw and of gender on D and Calv. The results were the same if the advanced non-linear mixed model was substituted by more standard analysis techniques. This study questions the relevance of using FeNO as a biomarker to evaluate local inflammation in COPD and points to a need for developing novel non-invasive biomarkers for research laboratory work and daily clinical practice.

AB - Although there is widespread interest in fractional exhaled nitric oxide (FeNO) as a non-invasive, time and cost effective biomarker for assessing airway inflammation in chronic obstructive pulmonary disease (COPD), its usefulness is still controversial. We examined the FeNO levels in clinically meaningful subgroups of COPD in a group of 91 COPD patients with FEV(1) 17-77% of predicted. Multiple flow rates FeNO at 10, 30, 50, 100 and 200 mL/s were measured and a two-compartment model was used to estimate the diffusion Capacity (D), alveolar NO concentration (Calv) and airway wall NO concentration (Caw). All patients had spirometry, assessment of symptoms with questionnaires and low-dose CT scan as well as assessment of weight and body composition. We examined the following subgroups of COPD: Patients with 1) Severe emphysema, 2) Chronic bronchitis, 3) Frequent exacerbations, 4) Loss of lean body mass and 5) Low fat-free mass index. We used advanced non-linear mixed model adjusted for age and gender. The modelled differences in D, Calv or Caw among COPD subgroups were small and not statistically significant. The analysis showed significant effects of current smoking on Caw and of gender on D and Calv. The results were the same if the advanced non-linear mixed model was substituted by more standard analysis techniques. This study questions the relevance of using FeNO as a biomarker to evaluate local inflammation in COPD and points to a need for developing novel non-invasive biomarkers for research laboratory work and daily clinical practice.

KW - Adult

KW - Aged

KW - Biological Markers

KW - Body Mass Index

KW - Breath Tests

KW - Disease Progression

KW - Exhalation

KW - Female

KW - Forced Expiratory Volume

KW - Humans

KW - Male

KW - Middle Aged

KW - Models, Theoretical

KW - Nitric Oxide

KW - Pulmonary Disease, Chronic Obstructive

KW - Pulmonary Emphysema

KW - Questionnaires

KW - Smoking

KW - Spirometry

U2 - 10.1016/j.rmed.2011.03.015

DO - 10.1016/j.rmed.2011.03.015

M3 - Journal article

C2 - 21530214

VL - 105

SP - 1338

EP - 1344

JO - Respiratory Medicine

JF - Respiratory Medicine

SN - 0954-6111

IS - 9

ER -