Fractional Exhaled Nitric Oxide Testing: Diagnostic Utility in Asthma, Chronic Obstructive Pulmonary Disease, or Asthma-chronic Obstructive Pulmonary Disease Overlap Syndrome.

Jeffrey A Miskoff,Moiuz Chaudhri,Asa Dewan

doi:10.7759/cureus.4864

Abstract

Asthma and chronic obstructive pulmonary disease (COPD) can present as unique conditions or as a combination known as asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS). These condition(s) can be categorized as obstructive conditions, causing inflammation of small airways leading to decrease airflow, mucus production, and bronchoconstriction. Asthma and COPD affect every age, gender, ethnicity, and socioeconomic status, thus increasing mortality and morbidity burden in our society. Fractional exhaled nitric oxide (FeNO) is an endogenous gaseous molecule which can be measured in the human breath test because of airway inflammation. It has been studied extensively as a marker of inflammation and has been incorporated into an algorithm for asthma management. The purpose of this study was to investigate whether FeNO testing can lead to a change in the diagnosis. A retrospective chart review of 95 patients with asthma, COPD, and ACOS was performed, and FeNO levels were recorded. Out of 95 patients, 36%, 24%, and 22% of the patients had an initial diagnosis of asthma, COPD, and ACOS, respectively. After the FeNO testing, the number of patients with the final diagnosis of asthma and ACOS increased, and COPD decreased. Our results support the utility of FeNO as a viable marker in diagnosing and managing complex cases of asthma, COPD, and ACOS.

Highlights

Asthma and chronic obstructive pulmonary disease (COPD) are respiratory conditions which commonly present with airflow limitation; the patient often complains of experiencing shortness of breath
Our analysis focused on patients who underwent Fractional exhaled nitric oxide (FeNO) testing starting November 1, 2016, to February 28th, 2017
Before FeNO testing, our cohort was characterized as 34 asthmatics, 23 with COPD, 21 with asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS), and 17 patients without the diagnosis of asthma, COPD, or ACOS

Summary

Introduction

Asthma and chronic obstructive pulmonary disease (COPD) are respiratory conditions which commonly present with airflow limitation; the patient often complains of experiencing shortness of breath. Asthma and COPD exacerbation present with increased airway inflammation, mucus production, and air trapping. Data suggests that COPD is the third- and fourth-most cause of deaths in the United States and the world, respectively [1,2,3]. Some reports suggest that COPD will be the third leading cause of deaths in the world by 2020 [4,5]. COPD is a chronic, indolent condition with a prevalence of 10% in the general population and 50% in smokers. The average cost per simple and complex COPD exacerbation admission is 7242 dollars and 20757 dollars respectively.

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