Do symptoms predict COPD in smokers?
BACKGROUND
The US Preventive Services Task Force recommends against spirometry in the absence of symptoms. However, as much as 50% of COPD cases in the United States remain undiagnosed.


METHODS
Report of symptoms, smoking history, and spirometric data were collected from subjects screened for a work-related medical evaluation (N = 3,955). Prevalence of airflow obstruction and respiratory symptoms were assessed. Sensitivity, specificity, positive and negative predictive values, and relative risks of predicting symptoms and smoking history for COPD were calculated.


RESULTS
Forty-four percent of smokers in our sample had airways obstruction (AO). Of these, 36% reported a diagnosis of or treatment for COPD. Odds ratio (95% CI) for AO with smoking (> or = 20 pack-years) was 3.73 (3.12- 4.45), 1.98 (1.73-2.27) for cough, 1.79 (1.55-2.08) for dyspnea, 1.95 (1.70-2.34) for sputum, and 2.59 (2.26-2.97) for wheeze. Respiratory symptoms were reported by 92% of smokers with AO, 86% smokers with restriction, 76% smokers with normal spirometry, and 73% of nonsmokers. Sensitivity (92% vs 90%), specificity (19% vs 22%), positive (47% vs 40%) and negative (75% vs 80%) predictive values for the presence of one or more symptoms were similar between smokers and all subjects.


CONCLUSIONS
COPD is underdiagnosed in the United States. Symptoms are frequent in subjects with AO and increase their risk for COPD, but add little beyond age and smoking history to the predictive value of spirometry. In view of the high prevalence of symptoms and their poor predictive value, a simpler and more effective approach would be to screen older smokers.
Ohar
Jill A
JA
Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157, USA. johar@wfubmc.edu
Sadeghnejad
Alireza
A
Meyers
Deborah A
DA
Donohue
James F
JF
Bleecker
Eugene R
ER
D000368:Aged; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology; D013902:Radiography, Thoracic; D012129:Respiratory Function Tests; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012907:Smoking / Q000453:epidemiology* / Q000503:physiopathology; D013147:Spirometry; D011795:Surveys and Questionnaires