prevalence of small-airway dysfunction among stable chronic obstructive pulmonary disease patients with different gold stages and its role in the impact of disease

Abstract

Chronic obstructive pulmonary disease (COPD) represents a main public health problem that in the latest Global Burden of Disease report has increased to the third most frequent cause of death worldwide.1 In recent years, increasing attention has been made to the role of the small airways in respiratory diseases, and their exact contribution to the pathophysiology of asthma and COPD continues to be clarified. It is thought that the small airways play a distinct role in specific disease patterns. Most of the available information is derived from clinical studies or review articles, and there is very little data available on the natural history of small airway disease during the onset or progression of asthma and COPD. It is difficult to make a comparison between studies of the role of the small airways because both asthma and COPD are heterogeneous conditions. Most studies have been performed in small population samples, and different techniques to characterize aspects of small airways function have been employed in order to assess inflammation and remodelling. Most studies have been done on small population samples, and various techniques to describe aspects of small airway function have been used to evaluate inflammation and regeneration. Most evaluation methods for small airway dysfunction are largely confined to research purposes, but some encouraging data support the use of some techniques in everyday clinical practice, especially for early-stage diseases, when subjects are usually asymptomatic and routine lung function tests may be within the normal range. In this context, more clinical trials and real-world responses are needed in large populations. 2 It has been proposed that lung function loss and increased airway responsiveness may be due to small airways dilation due to parenchymal damage. These structural changes can vary between patients, depending on different factors.3 In patients with COPD, small airway dysfunction (SAD) is considered a functional marker of the disease. However, the exact role of SAD in the clinical manifestation of COPD is not fully understood. Furthermore, it is not known whether SAD may have a relationship with the effects of the disease.4,5 In Italy, Ernesto Crisafulli’s et al. study shows that in COPD patients there is a progressive and increasing peripheral airway dysfunction among GOLD stage classifications. Distributions of SAD among COPD patients classified according to the old and the new GOLD stages (GOLD 1, 2, 3, 4 and GOLD A, B, C, D) was categorized in patients with (74%) and without (26%) SAD, respectively. The proportion of small airway dysfunction in GOLD B higher than GOLD A, at about 88% and 49% respectively. The prevalence of small airway dysfunction in GOLD D was highest with 96%, compared to about 61% of GOLD C and only 49% of GOLD A. Moreover, it demonstrated a strong relationship between SAD as assessed by means of Impulse Oscillometry (IOS) and impact of disease measured by CAT and that SAD is able to identify patients with high disease impact .6 In Viet Nam, these is little research of small airway dysfunction in COPD patients. Therfore we decided to study: “Prevalence of small- airway dysfunction among stable chronic obstructive pulmonary disease patients with different GOLD stages and its role in the impact of disease ” with 2 specifics objectives: 1. To investigate the prevalence and characteristics of small-airway dysfunction among stable chronic obstructive pulmonary disease patients at Unit for Management of Asthma and Chronic Obstructive Pulmonary disease outpatients- Bach Mai hospital. 2. To describes the impact of small-airway dysfunction in chronic obstructive pulmonary disease patients at Unit for Management of Asthma and Chronic Obstructive Pulmonary disease outpatients- Bach Mai hospital