Severity Staging of Chronic Obstructive Pulmonary Disease: Differences in Pre- and Post-Bronchodilator Spirometry

Abstract

Obstructive Lung Disease (GOLD) guidelines 1 recommended a simple classification of disease severity into four stages, using forced expiratory volume in one second (FEV1) of the predicted value, and where all values refer to post-bronchodilator FEV1. Bronchodilator test (BDT), however, is not always performed in clinical practice and the staging of COPD severity is frequently based on pre-bronchodilator spirometry.For the past few years, an increasing number of articles on COPD have used the GOLD guidelines for severity staging. Although there were studies apparently using the post-BDT spirometry for COPD staging, 2-4 a number of previous studies have also used pre-bronchodilator values, or did not specify which one was used when applying the GOLD guidelines. [5][6][7][8] While irreversible airflow obstruction is the hallmark of COPD, many patients with COPD have a reversible component. 9 Original Article DOI 10.3349/ymj.2009.50.5.672 pISSN: 0513-5796, eISSN: 1976-2437 Yonsei Med J 50 (5) Purpose: The Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines for chronic obstructive pulmonary disease (COPD) uses the post-bronchodilator spirometry for diagnosis and severity staging. We evaluated differences in the severity classification of COPD, based on pre-and post-bronchodilator spirometry. Materials and Methods: From 2000 to 2004, 207 COPD patients who underwent spirometry before and after inhalation of 400 µg of fenoterol were analyzed. A responder to the bronchodilator test (BDT) was defined by the American Thoracic Society (ATS) as an increase in forced expiratory volume in one second (FEV1) or forced vital capacity ≥ 12% and ≥ 200 mL, and by the European Respiratory Society (ERS) as an increase in FEV1 ≥ 10% of the predicted value. COPD severity was classified according to the 2008 GOLD guidelines. Results: For the entire study population, the FEV1 increased by 11.8 ± 12.5% of baseline after BDT and 41.1% and 27.1% of subjects were classified as responders using the ATS and ERS criteria, respectively. Based on pre-BDT spirometry, 55, 85, 58, and 9 patients were classified as Stage I-IV COPD, respectively. Sixty-seven (32.4%) patients changed severity staging after BDT, including 20.0%, 28.2%, 44.8%, and 66.7% of pre-BDT patients Stages I through IV, respectively. More ATS or ERS BDT-responders had a change in severity staging than non-responders (52.9% vs. 18.9% and 62.5% vs. 21.2%, both p < 0.001). Conclusion: Our data suggest that the severity staging of COPD using pre-BDT spirometry might lead to significant differences as compared to staging, based on post-BDT spirometry, as recommended by the current GOLD guidelines.

Extensive Surgical and Comprehensive Postoperative Medical Management for Cystic Fibrosis Chronic Rhinosinusitis

“…Spirometry was performed using American Thoracic Society criteria as part of routine CF clinic visits. 16 Spirometry results were collected from outpatient values, but when associated with pulmonary exacerbations, spirometry before discharge was recorded. Outcome measures were tested for significance using paired t-tests or ANOVA as appropriate.…”

The Importance of the Assessment of Pulmonary Function in COPD

“…It should be noted that the post-bronchodilator FEV 1 should be used to determine severity stage. It is more reproducible than the pre-bronchodilator FEV 1 (16). Stage I or “mild” COPD is defined as a FEV 1 /FVC ratio of <0.7 and an FEV 1 >80% predicted; Stage II is an FEV 1 of 50-79% predicted; Stage III 30-49% predicted, Stage IV <30% predicted.…”