Diagnostic value of oral prednisolone test for chronic obstructive pulmonary disorders

Abstract

Purpose: We wanted to determine the diagnostic value of an oral prednisolone test for chronic obstructive pulmonary disorders.

Methods: Two hundred thirty-three patients with cough for longer than 14 days, without known chronic obstructive pulmonary disease (COPD) or asthma, participated in a diagnostic study in Dutch primary care between 2006 and 2009. These patients used a 14-day prednisolone test of 30 mg/d and recorded before-after bronchodilator measurements of forced expiratory volume in 1 second (FEV(1)). An expert panel determined the presence or absence of COPD and asthma based on an extensive diagnostic workup. The proportion of responders to the prednisolone test (increased FEV(1) exceeding 200 mL or 12% of baseline) per diagnosis group was compared, and the diagnostic value of the test was quantified by logistic regression and analysis of the area under the receiver operating characteristic curve (ROC area).

Results: In patients with COPD, 23% (14 of 61) responded to the test; in patients with asthma 4% (1 of 25) responded; in patients with asthma and COPD, 7% (1 of 14) responded; and in those without asthma or COPD, 11% (14 of 133) responded. Being a responder was, unexpectedly, associated with COPD (OR = 2.4; 95% confidence interval [CI], 1.1-5.2). After multivariate analysis, adjusting for age, sex, and smoking, the OR = 2.0 (95% CI, 0.8-5.0) and the ROC area did not increase (0.78; 95% CI, 0.72-0.85 vs 0.79; 95% CI, 0.72-0.85).

Conclusion: A response to a prednisolone test was suggestive of COPD, but added no diagnostic value to more easily obtainable characteristics.

Figure 1.

Flowchart of the study and the participants. COPD = chronic obstructive pulmonary disease. ^a Spirometry after the prednisolone test took place maximally 5 days after the 14th day of prednisolone treatment.