THE CLINICAL-EVALUATION FOR DIAGNOSING OBSTRUCTIVE AIRWAYS DISEASE INHIGH-RISK PATIENTS

Objective: We measured the ability of the medical history, physical ex amination, and peak flowmeter in diagnosing any degree of obstructive airways disease (OAD). Design: Prospective comparison of historical an d physical findings with independently measured spirometry. Setting: U niversity outpatient clinic. Patients: Ninety-two adult consecutive ou tpatient volunteers with a self-reported history of smoking, asthma, c hronic bronchitis, or emphysema. Measurements: All subjects completed a pulmonary history questionnaire and received peak now (PF) and spiro metric testing. The subjects were independently examined for 12 pulmon ary physical signs by four internists blinded to all other results. Mu ltivariable analysis was used to create a diagnostic model to predict OAD as diagnosed by spirometry (FEV(1) < 80 percent of predicted not s econdary to restrictive disease, or FEV(1)/FVC less than 0.7). Results : The best model diagnosed OAD when any of three variables were presen t-a history of smoking more than 30 pack-years, diminished breath soun ds, or peak now less than 350 L/min. This model had a sensitivity of 9 8 percent and specificity of 46 percent. In addition, the model detect ed all subjects with probable restrictive lung disease. Thirty-one per cent of subjects had none of these variables and were at very low (3 p ercent) risk of OAD. Fifty percent of subjects with one or more abnorm al variables had OAD. Conclusions: The history, physical examination, and peak flowmeter can be used to screen high-risk patients for OAD. U sing this diagnostic model, 31 percent of subjects could be classified at very low risk of OAD while half of those referred for spirometry w ould have abnormal results.