Validity of a questionnaire-based diagnosis of chronic obstructive pulmonary disease in a general population-based study

Table 1 Characteristics of the study population

	FEV₁/FVC <0.7 (GOLD) n = 366*	FEV₁/FVC <1.645 SD below predicted (ATS/ERS) n = 163*	All N = 3,892
Physician-diagnosed COPD,%	5.7	9.8	0.8
Chronic bronchitis symptoms,%	4.6	7.4	2.3
Women,%	49.2	66.9	52.5
Age (mean ± SD), yrs	58.3 ± 9.5	54.9 ± 10.3	51.7 ± 10.6
BMI (mean ± SD), kg/m²	25.6 ± 3.9	25 ± 3.8	26.1 ± 4
Spirometry
FEV₁ (L) (mean ± SD)	2.7 ± 0.8	2.5 ± 0.8	3.3 ± 0.8
FEV₁% (mean ± SD)	65.1 ± 5.3	61.9 ± 6.3	78.0 ± 6.3
FEV₁/FVC (mean ± SD)	64.9 ± 5.3	61.7 ± 6.3	77.9 ± 6.4
Dyspnea,%	6.3	9.2	6.3
Wheezing,%	24.6	31.3	14.6
Treatment with respiratory drugs,%	4.6	8	1.1
Smoking habits
Never-smokers,%	29.8	27.6	47.7
Former smokers,%	38.8	35.6	36.2
Current smokers,%	31.4	36.8	16.1
Pack/years in current and former smokers (mean ± SD)	22.6 ± 15.5	22.2 ± 13.8	15 ± 12.2

*In the whole study population, 366 subjects (9.4%) had COPD according to the GOLD criteria; 163 (4.2%) had COPD according to LLN criteria.
ATS = American Thoracic Society; BMI = body mass index; COPD = chronic obstructive pulmonary disease; ERS = European Respiratory Society; FEV₁ = forced expiratory volume in 1 second; FEV₁% =% of FEV₁ compared to the predicted value; FEV₁/FVC = FEV₁/forced vital capacity ratio; GOLD = Global Initiative for Chronic Obstructive Lung Disease; SD = standard deviation.

ISSN: 1471-2466