Symptomatic smokers without COPD have physiological changes heralding the development of COPD

Abstract

BackgroundChronic Obstructive Pulmonary Disease (COPD) is a major health problem, mainly due to cigarette smoking. Most studies in COPD are dedicated to fully developed COPD in older subjects, even though development of COPD may start soon after smoking initiation. Therefore, there is a need to diagnose this “early disease” by detecting the initial events responsible for ultimate development of COPD.MethodsMeasurement of maximum mid expiratory flow between 25–75 of vital capacity (MMEF) in a routine spirometry, that detects small airways disease, was used to investigate if MMEF abnormalities in smokers without COPD (noCOPD) would relate to respiratory symptoms and identify smokers that might progress to COPD. For this purpose we studied 511 smokers, 302 COPD and 209 noCOPD, followed long term with spirometry including MMEF, CO diffusion capacity (DLCO), 6-minute walking test (6MWT), MRC Dyspnoea Scale, and COPD Assessment Test (CAT). Three spirometries V1,V2,V3 (5±2.5 and 10±4 years apart respectively from V1) were performed to assess functional decline and development of COPD.Results65% of noCOPD had an abnormal MMEF (<80%) and 38% an abnormal DLCO. NoCOPD with MMEF<80% performed worse in the 6MWT (p=0.01), were more dyspnoeic (p=0.01) and had higher prevalence of chronic bronchitis than noCOPD with MMEF>80% (p=0.04). 21% of noCOPD with MMEF<80%, and 2.7% with MMEF>80% developed COPD by V3 (p=0.0004).ConclusionsThe MMEF, a functional test available in a routine spirometry, can detect early lung abnormalities and identify the subset of symptomatic smokers with pathologic changes that might lead to COPD.

Small airway function measured using forced expiratory flow between 25% and 75% of vital capacity and its relationship to airflow limitation in symptomatic ever-smokers: a cross-sectional study

“…Our study has limitations. It was a cross-sectional study but the value of FEF 25-75 as a monitoring tool has also been demonstrated longitudinally15 21 22 and our study provided a larger sample confirming the prevalence of low FEF 25-75 in smokers with and without AL. FEF 25-75 is a highly variable spirometric measure but we used FEF 25-75 z-score to optimise the interpretive accuracy.…”

“…We hypothesised that low FEF 25-75 , would be ubiquitous in patients with AL, as this has been demonstrated to precede the development of AL 21 22. Furthermore, we hypothesised that patients with low FEF 25-75 but without AL would have physiological indicators of the risk of developing AL, even after the correction for potential confounders such as smoking history.…”

Chronic Bronchitis Affects Outcomes in Smokers without Chronic Obstructive Pulmonary Disease (COPD)

“…During follow-up, 14% of smokers with noCOPD developed COPD, of which 63% did not have CB and 37% had it, indicating that in this population, having CB does not affect the FEV 1 decline neither is it a risk factor for the eventual development of COPD. Contrary to the noCOPD, the FEV 1 decline in COPD smokers was dependent in part on the presence of CB, since COPD with CB decline more than COPD without CB (41 ± 48 vs. 22 ± 53 mL/year; p < 0.01, Table 2 ), and in part on the smoking activity, which further accelerates the FEV 1 decline [ 18 ].…”

“…An explanation for this symptom probably resides in the extra amount of ventilation necessary for any degree of work even in noCOPD smokers, as demonstrated in a recent report [ 24 ]. These smokers might have early airway abnormalities and abnormal DLco, secondary to gas exchange abnormalities aggravated by the presence of CB, explaining the presenting symptoms [ 18 ]. Interestingly, the percentage of patients with a severity of dyspnoea above mMRC ≥ 2 was similar in chronic bronchitis with and without COPD, probably due to the fact that smokers noCOPD were able to exercise more than smokers with COPD, thus experimenting similar degrees of dyspnoea for a heavier exercise load.…”

Chronic obstructive lung diseases as a risk factor for severe COVID-19 (review)

“…Эпидемиологические исследования показывают, что в России распространенность ХОБЛ среди лиц с респираторными симптомами составляет 21,8 %, а в общей популяции -15,3 % [6,14]. 65 % курящих имеют патологические изменения в легких, которые могут привести к ХОБЛ [13]. Даже у тех длительно курящих людей, которые считают себя здоровыми, выраженные нарушения бронхиальной проходимости отмечались в 15 % случаев [5].…”