چکیده (انگلیسی):

Background:Chronic lung disease is common and often under-diagnosed.
Methods:To test a simple rule for conducting spirometry we reviewed spirograms from two populations,
occupational medicine evaluations (OME) conducted by Saint Louis and Wake Forest Universities at 3 sites (n= 3260,
mean age 64.14 years, 95 % CI 58.94–69.34, 97 % men) and conducted by Wake Forest University preop clinic (POC) at
one site (n= 845, mean age 62.10 years, 95 % CI 50.46–73.74, 57 % men). This retrospective review of database
information that the first author collected prospectively identified rates, types, sensitivity, specificity and positive and
negative predictive value for lung function abnormalities and associated mortality rate found when conducting
spirometry based on the 20/40 rule (≥20 years of smoking in those aged≥40 years) in the OME population. To
determine the reproducibility of the 20/40 rule for conducting spirometry, the rule was applied to the POC population.
Results:A lung function abnormality was found in 74 % of the OME population and 67 % of the POC population.
Sensitivity of the rule was 85 % for an obstructive pattern and 77 % for any abnormality on spirometry. Positive and
negative predictive values of the rule for a spirometric abnormality were 74 and 55 %, respectively. Patients with an
obstructive pattern were at greater risk of coronary heart disease (odds ratio (OR) 1.39 [confidence interval (CI) 1.00–1.
93] vs. normal) and death (hazard ratio (HR) 1.53, 95 % CI 1.20–1.84) than subjects with normal spirometry. Restricted
spirometry patterns were also associated with greater risk of coronary disease (odds ratio (OR) 1.7 [CI 1.23–2.35]) and
death (Hazard ratio 1.40, 95 % CI 1.08–1.72).
Conclusions:Smokers (≥20 pack years) age≥40 years are at an increased risk for lung function abnormalities and
those abnormalities are associated with greater presence of coronary heart disease and increased all-cause mortality.
Use of the 20/40 rule could provide a simple method to enhance selection of candidates for spirometry evaluation in
the primary care setting.