Alternative definitions of chronic bronchitis and their correlation with CT parameters

Abstract

IntroductionPhenotyping of chronic bronchitis (CB) using COPD assessment tool (CAT) scores and St George’s Respiratory Questionnaire (SGRQ) has rarely been attempted. The present study defined CB using CAT 1 and 2 scores and the questions on the severity of cough and sputum from the SGRQ. Furthermore, the predictability of CT parameters was also assessed for each CB definition.Materials and methodsPatients enrolled in the Korean Obstructive Lung Disease study from June 2005 to October 2015 were evaluated for this study. The patients were spirometrically diagnosed with COPD and had a smoking history of >10 pack-years. Volumetric CT scans were performed for each patient upon enrollment in the cohort. Two definitions of CB using CAT 1/2 scores and SGRQ questions were used to phenotype CB among the study patients. Receiver operating characteristic curve analysis was performed to estimate the predictability of CT parameters for the CB phenotypes.ResultsUsing CAT 1/2 scores, 57 of 279 (20.4%) patients had CB, and 178 of 573 (31.1%) had CB when the SGRQ questions were used to phenotype it. Total CAT and SGRQ scores were significantly higher in the CB group than those in the non-CB group for both definitions of CB. Forced expiratory volume in 1 second was lower for both CAT-defined and SGRQ-defined CB than that in the non-CB group. Mean wall thickness was significantly higher for both CB groups than in the non-CB group. Expiratory lung volume was higher and mean lung density was significantly lower for the SGRQ-defined CB group than non-CB group.ConclusionThe 2 CB definitions using CAT scores and the SGRQ questions correlated with associated CT airway parameters. SGRQ-defined CB better reflected the accompaniment of small airway obstruction when compared with CAT-defined CB.

<p>Mixed Phenotype of Emphysema and Airway Wall Thickening Is Associated with Frequent Exacerbation in Chronic Obstructive Pulmonary Disease Patients</p>

“…[20][21][22][23] In addition, we assumed that the component of bronchial wall thickening was added to the emphysema component, which eventually contributed to poor outcome. Chronic bronchitis patients with COPD are characterized by airway wall thickening as detected via thoracic CT. 6,14 Such patients are often more symptomatic and show more frequent exacerbations compared to patients without chronic bronchitis. [24][25][26][27] Furthermore, MWA% is also correlated with small airway disease, 10 and it may also have had a detrimental effect on COPD patients with mixed phenotype.…”

“…In accordance with previous studies, the cut-off level dividing normal lung density and area of low attenuation was -950 HU. [13][14][15] A modified sharpening filter with a 3×9×3 kernel size was used for more accurate airway measurement. The validation process using polyacrylic tubes was performed beforehand, and the software discriminated the airway lumen and the inner and outer boundaries of the airway wall automatically by the full-width-maximum method.…”

“…The validation process using polyacrylic tubes was performed beforehand, and the software discriminated the airway lumen and the inner and outer boundaries of the airway wall automatically by the full-width-maximum method. [14][15][16] Wall area (WA) percentage, which was defined as WA/(WA + lumen area (LA)) × 100, was measured in each segmental bronchus. The mean value of each dimension value was used for statistical analyses.…”

<p>CAT Score and SGRQ Definitions of Chronic Bronchitis as an Alternative to the Classical Definition</p>

“…[18][19][20] In addition, various studies have used other definitions to classify COPD patients into CB and non-CB groups. 12,[21][22][23][24][25] Therefore, study heterogeneity has imposed some limitations on interpreting the prevalence and outcome of CB, and there have been several interesting reports regarding differences in clinical outcomes in CB patients classified according to different definitions. 24,25 Many studies have used the St. George's Respiratory Questionnaire (SGRQ) score to define CB.…”

“…12,[21][22][23][24][25] Therefore, study heterogeneity has imposed some limitations on interpreting the prevalence and outcome of CB, and there have been several interesting reports regarding differences in clinical outcomes in CB patients classified according to different definitions. 24,25 Many studies have used the St. George's Respiratory Questionnaire (SGRQ) score to define CB. 26,27 The SGRQ consists of 76 questions correlated with health-related quality of life in COPD patients.…”