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Cross-sectional analysis of the utility of pulmonary function tests in predicting emphysema in ever-smokers.

Hesselbacher SE, Ross R, Schabath MB, Smith EO, Perusich S, Barrow N, Smithwick P, Mammen MJ, Coxson H, Krowchuk N, Corry DB, Kheradmand F - Int J Environ Res Public Health (2011)

Bottom Line: We enrolled 224 ever-smokers (current or former) over the age of 40.Standardized airway wall thickness was increased in subjects with airflow obstruction, but did not correlate with emphysema severity.Airway wall thickness quantified by CT morphometry was associated with airflow limitation, but not with emphysema indicating that the heterogeneous nature of lung disease in smokers may represent distinct phenotypes.

View Article: PubMed Central - PubMed

Affiliation: Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA. hesselba@bcm.tmc.edu

ABSTRACT
Emphysema is largely an under-diagnosed medical condition that can exist in smokers in the absence of airway obstruction. We aimed to determine the sensitivity and specificity of pulmonary function tests (PFTs) in assessing emphysema using quantitative CT scans as the reference standard. We enrolled 224 ever-smokers (current or former) over the age of 40. CT of thorax was used to quantify the low attenuation area (% emphysema), and to measure the standardized airway wall thickness. PFTs were used individually and in combination to predict their ability to discriminate radiographic emphysema. Significant emphysema (>7%) was detected in 122 (54%) subjects. Twenty six (21%) emphysema subjects had no evidence of airflow obstruction (FEV(1)/FVC ratio <70%), while all subjects with >23% emphysema showed airflow obstruction. The sensitivity and specificity of spirometry for detecting radiographic emphysema were 79% and 75%, respectively. Standardized airway wall thickness was increased in subjects with airflow obstruction, but did not correlate with emphysema severity. In this cohort of lifetime ever-smokers, PFTs alone were inadequate for diagnosing emphysema. Airway wall thickness quantified by CT morphometry was associated with airflow limitation, but not with emphysema indicating that the heterogeneous nature of lung disease in smokers may represent distinct phenotypes.

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Related in: MedlinePlus

Likelihood ratios (LR) for detection of emphysema from pulmonary function tests. The positive (+) and negative (−) likelihood ratios for detection of emphysema as assessed by individual PFTs are shown where a LR+ of >10, or LR− of <0.1 represent conclusive increase in the likelihood of the presence, or absence of emphysema respectively.
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f2-ijerph-08-01324: Likelihood ratios (LR) for detection of emphysema from pulmonary function tests. The positive (+) and negative (−) likelihood ratios for detection of emphysema as assessed by individual PFTs are shown where a LR+ of >10, or LR− of <0.1 represent conclusive increase in the likelihood of the presence, or absence of emphysema respectively.

Mentions: We next measured the sensitivity and specificity of individual pulmonary function tests for predicting emphysema (LAA ≥ 7%) (Table 3). Positive and negative likelihood ratios (LR+, LR− respectively), and positive and negative predictive values (PPV and NPV respectively) for each pulmonary function test were also determined (Figure 2).


Cross-sectional analysis of the utility of pulmonary function tests in predicting emphysema in ever-smokers.

Hesselbacher SE, Ross R, Schabath MB, Smith EO, Perusich S, Barrow N, Smithwick P, Mammen MJ, Coxson H, Krowchuk N, Corry DB, Kheradmand F - Int J Environ Res Public Health (2011)

Likelihood ratios (LR) for detection of emphysema from pulmonary function tests. The positive (+) and negative (−) likelihood ratios for detection of emphysema as assessed by individual PFTs are shown where a LR+ of >10, or LR− of <0.1 represent conclusive increase in the likelihood of the presence, or absence of emphysema respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3108112&req=5

f2-ijerph-08-01324: Likelihood ratios (LR) for detection of emphysema from pulmonary function tests. The positive (+) and negative (−) likelihood ratios for detection of emphysema as assessed by individual PFTs are shown where a LR+ of >10, or LR− of <0.1 represent conclusive increase in the likelihood of the presence, or absence of emphysema respectively.
Mentions: We next measured the sensitivity and specificity of individual pulmonary function tests for predicting emphysema (LAA ≥ 7%) (Table 3). Positive and negative likelihood ratios (LR+, LR− respectively), and positive and negative predictive values (PPV and NPV respectively) for each pulmonary function test were also determined (Figure 2).

Bottom Line: We enrolled 224 ever-smokers (current or former) over the age of 40.Standardized airway wall thickness was increased in subjects with airflow obstruction, but did not correlate with emphysema severity.Airway wall thickness quantified by CT morphometry was associated with airflow limitation, but not with emphysema indicating that the heterogeneous nature of lung disease in smokers may represent distinct phenotypes.

View Article: PubMed Central - PubMed

Affiliation: Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA. hesselba@bcm.tmc.edu

ABSTRACT
Emphysema is largely an under-diagnosed medical condition that can exist in smokers in the absence of airway obstruction. We aimed to determine the sensitivity and specificity of pulmonary function tests (PFTs) in assessing emphysema using quantitative CT scans as the reference standard. We enrolled 224 ever-smokers (current or former) over the age of 40. CT of thorax was used to quantify the low attenuation area (% emphysema), and to measure the standardized airway wall thickness. PFTs were used individually and in combination to predict their ability to discriminate radiographic emphysema. Significant emphysema (>7%) was detected in 122 (54%) subjects. Twenty six (21%) emphysema subjects had no evidence of airflow obstruction (FEV(1)/FVC ratio <70%), while all subjects with >23% emphysema showed airflow obstruction. The sensitivity and specificity of spirometry for detecting radiographic emphysema were 79% and 75%, respectively. Standardized airway wall thickness was increased in subjects with airflow obstruction, but did not correlate with emphysema severity. In this cohort of lifetime ever-smokers, PFTs alone were inadequate for diagnosing emphysema. Airway wall thickness quantified by CT morphometry was associated with airflow limitation, but not with emphysema indicating that the heterogeneous nature of lung disease in smokers may represent distinct phenotypes.

Show MeSH
Related in: MedlinePlus