Table 1.
Distribution of BDR and Discrimination Statistics, by Physician-assigned Diagnosis for Different BDR Definitions
| Asthma and COPD (n = 833) | Asthma vs. COPD |
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|---|---|---|---|---|---|
| BDR Definition | Asthma (n = 3,519) | COPD (n = 2,436) | AUC (95% CI) | Sensitivity, Specificity | |
| ΔFEV1 or ΔFVC ⩾12% and ⩾200 ml | 631/3,196 (19.7%) | 224/757 (29.6%) | 552/2,239 (24.7%) | 0.597 (0.572, 0.622) | 0.55, 0.30 |
| ΔFEV1 ⩾12% and ⩾200 ml | 548/3,229 (17.0%) | 179/760 (23.6%) | 317/2,242 (14.1%) | 0.659 (0.629, 0.690) | 0.58, 0.21 |
| ΔFVC ⩾12% and ⩾200 ml | 298/3,228 (9.2%) | 143/758 (18.9%) | 409/2,256 (18.1%) | 0.592 (0.562, 0.622) | 0.42, 0.43 |
| ΔFEV1 ⩾15% and ⩾400 ml | 228/3,229 (7.1%) | 42/760 (5.5%) | 52/2,242 (2.3%) | 0.727 (0.652, 0.803) | 0.80, 0.07 |
| ΔFEV1 >10% pred | 482/3,176 (15.2%) | 114/750 (15.2%) | 177/2,207 (8.0%) | 0.571 (0.555, 0.586) | 0.15, 0.92 |
| ΔFVC >10% pred | 279/3,175 (8.8%) | 130/748 (17.4%) | 326/2,221 (14.7%) | 0.578 (0.562, 0.593) | 0.09, 0.86 |
| ΔFEV1 or ΔFVC >10% pred | 569/3,143 (18.1%) | 174/747 (23.3%) | 396/2,204 (18.0%) | 0.505 (0.490, 0.521) | 0.18, 0.82 |
| High-likelihood asthma or COPD (1) | Asthma HL (n = 1,820) | COPD HL (n = 1,260) | AUC (95% CI) | Sensitivity, Specificity | |
| ΔFEV1 or ΔFVC ⩾12% and ⩾200 ml | 351/1,658 (21.2%) | 338/1,222 (27.7%) | 0.619 (0.586, 0.652) | 0.54, 0.26 | |
| ΔFEV1 ⩾12% and ⩾200 ml | 313/1,681 (18.6%) | 176/1,223 (14.4%) | 0.703 (0.664, 0.742) | 0.56, 0.17 | |
| ΔFVC ⩾12% and ⩾200 ml | 153/1,676 (9.1%) | 260/1,227 (21.2%) | 0.602 (0.562, 0.642) | 0.42, 0.40 | |
| ΔFEV1 ⩾15% and ⩾400 ml | 148/1,681 (8.8%) | 24/1,223 (2.0%) | 0.765 (0.673, 0.857) | 0.80, 0.04 | |
| ΔFEV1 >10% pred | 275/1,652 (16.6%) | 89/1,203 (7.4%) | 0.592 (0.572, 0.613) | 0.16, 0.93 | |
| ΔFVC >10% pred | 134/1,647 (8.1%) | 210/1,207 (17.4%) | 0.614 (0.593, 0.635) | 0.08, 0.83 | |
| ΔFEV1 or ΔFVC >10% pred | 315/1,629 (19.3%) | 242/1,202 (20.1%) | 0.508 (0.487, 0.530) | 0.19, 0.80 | |
Definition of abbreviations: AUC = area under the curve; BDR = bronchodilator responsiveness; CI = confidence interval; COPD = chronic obstructive pulmonary disease; HL = high likelihood; ROC = receiver operating characteristic; pred = predicted.
Δ denotes the difference between the pre- and post-bronchodilator values. This table shows the distribution of BDR for different BDR definitions across patients diagnosed with asthma and/or COPD (top) and among patients with high-likelihood asthma or COPD (bottom). The last column displays results from a ROC curve analysis evaluating the ability to discriminate between asthma-only and COPD-only patients (1). High-likelihood asthma was defined as physician diagnosis of asthma only, asthma symptom onset before age 40, and less than 5 pack-years of smoking exposure. High-likelihood COPD was defined as physician diagnosis of COPD only, COPD symptom onset at age greater than 40, at least 10 pack-years smoking exposure, and post-bronchodilator FEV1/FVC <0.7.