Limits...
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.

Show MeSH

Related in: MedlinePlus

Airway wall thickness is increased in ever smokers with emphysema and airway obstruction. (A) A representative images of the internal perimeter of CT identified airway in subjects with similar degree of CT emphysema (11 and 12%) and with (left panel) or without (right panel) airflow obstruction. (B) Linear regression correlation of airway wall thickness (AWT-Pi10) was versus FEV1/FVC ratio (solid line; P = 0.0005; r = −0.3981) and FEV1% predicted (dashed line; P = 0.003; r = −0.3457) in 73 subjects with % emphysema between 7–23%. (C) AWT was plotted against % emphysema, with linear regression in the same group of 73 subjects. The correlation was not significant (P = 0.81, r = 0.0284). (D) Airway wall thickness (AWT-Pi10) measurements were assessed in 73 ever smokers with similar degree of emphysema (range 7 to 23%) comparing those with no airflow limitation (FEV1/FVC ≥ 70; N = 24) and with airflow obstruction (FEV1/FVC < 70; N = 49).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4-ijerph-08-01324: Airway wall thickness is increased in ever smokers with emphysema and airway obstruction. (A) A representative images of the internal perimeter of CT identified airway in subjects with similar degree of CT emphysema (11 and 12%) and with (left panel) or without (right panel) airflow obstruction. (B) Linear regression correlation of airway wall thickness (AWT-Pi10) was versus FEV1/FVC ratio (solid line; P = 0.0005; r = −0.3981) and FEV1% predicted (dashed line; P = 0.003; r = −0.3457) in 73 subjects with % emphysema between 7–23%. (C) AWT was plotted against % emphysema, with linear regression in the same group of 73 subjects. The correlation was not significant (P = 0.81, r = 0.0284). (D) Airway wall thickness (AWT-Pi10) measurements were assessed in 73 ever smokers with similar degree of emphysema (range 7 to 23%) comparing those with no airflow limitation (FEV1/FVC ≥ 70; N = 24) and with airflow obstruction (FEV1/FVC < 70; N = 49).

Mentions: In this cohort, we determined that all ever-smokers with >23% emphysema had concurrent airflow obstruction. Therefore, we next analyzed the contribution of airway wall thickness (AWT-Pi10) to airflow obstruction and emphysema, in a subgroup of ever-smokers with >7% and < or equal to 23% emphysema (representative images shown in (Figure 4A).


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)

Airway wall thickness is increased in ever smokers with emphysema and airway obstruction. (A) A representative images of the internal perimeter of CT identified airway in subjects with similar degree of CT emphysema (11 and 12%) and with (left panel) or without (right panel) airflow obstruction. (B) Linear regression correlation of airway wall thickness (AWT-Pi10) was versus FEV1/FVC ratio (solid line; P = 0.0005; r = −0.3981) and FEV1% predicted (dashed line; P = 0.003; r = −0.3457) in 73 subjects with % emphysema between 7–23%. (C) AWT was plotted against % emphysema, with linear regression in the same group of 73 subjects. The correlation was not significant (P = 0.81, r = 0.0284). (D) Airway wall thickness (AWT-Pi10) measurements were assessed in 73 ever smokers with similar degree of emphysema (range 7 to 23%) comparing those with no airflow limitation (FEV1/FVC ≥ 70; N = 24) and with airflow obstruction (FEV1/FVC < 70; N = 49).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4-ijerph-08-01324: Airway wall thickness is increased in ever smokers with emphysema and airway obstruction. (A) A representative images of the internal perimeter of CT identified airway in subjects with similar degree of CT emphysema (11 and 12%) and with (left panel) or without (right panel) airflow obstruction. (B) Linear regression correlation of airway wall thickness (AWT-Pi10) was versus FEV1/FVC ratio (solid line; P = 0.0005; r = −0.3981) and FEV1% predicted (dashed line; P = 0.003; r = −0.3457) in 73 subjects with % emphysema between 7–23%. (C) AWT was plotted against % emphysema, with linear regression in the same group of 73 subjects. The correlation was not significant (P = 0.81, r = 0.0284). (D) Airway wall thickness (AWT-Pi10) measurements were assessed in 73 ever smokers with similar degree of emphysema (range 7 to 23%) comparing those with no airflow limitation (FEV1/FVC ≥ 70; N = 24) and with airflow obstruction (FEV1/FVC < 70; N = 49).
Mentions: In this cohort, we determined that all ever-smokers with >23% emphysema had concurrent airflow obstruction. Therefore, we next analyzed the contribution of airway wall thickness (AWT-Pi10) to airflow obstruction and emphysema, in a subgroup of ever-smokers with >7% and < or equal to 23% emphysema (representative images shown in (Figure 4A).

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