Spirometric indices of early airflow impairment in individuals at risk of developing COPD: Spirometry beyond FEV1/FVC

Abstract

Spirometry is the current gold standard for diagnosing and monitoring the progression of Chronic Obstructive Pulmonary Disease (COPD). However, many current and former smokers who do not meet established spirometric criteria for the diagnosis of this disease have symptoms and clinical courses similar to those with diagnosed COPD. Large longitudinal observational studies following individuals at risk of developing COPD offer us additional insight into spirometric patterns of disease development and progression. Analysis of forced expiratory maneuver changes over time may allow us to better understand early changes predictive of progressive disease. This review discusses the theoretical ability of spirometry to capture fine pathophysiologic changes in early airway disease, highlights the shortcomings of current diagnostic criteria, and reviews existing evidence for spirometric measures which may be used to better detect early airflow impairment.

<p>FEF_25-75% Values in Patients with Normal Lung Function Can Predict the Development of Chronic Obstructive Pulmonary Disease</p>

“…Instead, several studies have investigated the parameters associated with FEF 25-75% and obstructive disease. 20 Although objective criteria for analysis are lacking, the concavity of the flow-volume curve is often used for classifying the obstructive pattern of patients. 20…”

“…The impairment of FEF 25-75% indicates the impairment of medium-sized and small airways. 20 Compromised FEF 25-75% is frequently observed in patients with bronchial hyper-responsiveness in asthma or allergic rhinitis. 21 Children with allergic rhinitis/asthma and decreased FEF 25-75% have elevated values of fractional exhaled nitric oxide.…”

“…Instead, several studies have investigated the parameters associated with FEF 25-75% and obstructive disease. 20 Although objective criteria for analysis are lacking, the concavity of the flow-volume curve is often used for classifying the obstructive pattern of patients. 20 Recently, the global concavity index (100*[reference FEF50%–measured FEF50%]/reference FEF50%) and peripheral concavity index ([reference FEF75%-measured FEF75%]/reference FEF75%) were reported to be related to obstructive disease.…”

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

“…1 Our goal was to use the information commonly obtained by routine spirometry further, which could be useful for identifying early airflow abnormalities predictive of the development of COPD. 38 In our analysis, FEV 1 to SVC ratio of < 0.7 was not associated with high mMRC, CAT score, or chronic bronchitis, likely because the participants in the study had relatively preserved lung function and they were fairly asymptomatic. In a similar study by Saint-Pierre et al 7 that included adults with a prebronchodilator FEV 1 to FVC ratio of more than the LLN and total lung capacity of more than the LLN, the average of mMRC was only 1.5 in those FEV 1 to SVC ratio of less than the…”

Early diagnosis of COPD: myth or a true perspective

“…The alternative spirometric ratios used to investigate earlier changes not detected by FEV 1 /FVC or FEV 1 and that detect small airway abnormalities, air trapping and hyperinflation are described below [42].…”