TABLE 1.
Overview of the patient characteristics from the derivation and validation databases
| Derivation database# | Validation database¶ | |
| Patients | 9297 | 3142+ |
| Diagnosis | ||
| COPD | 1716 (18.5) | 555 (17.7) |
| Asthma | 4125 (44.4) | 685 (21.8) |
| Probable asthma | 836 (26.6) | |
| ACOS | 711 (7.6) | 247 (7.9) |
| Other | 2745 (29.5) | 818 (26.0) |
| Patient characteristics | ||
| Male | 4146 (44.6) | 1347 (42.9) |
| Smoked | ||
| Never smoked | 2833 (30.5) | 1182 (37.7) |
| Ever smoked | 6464 (69.5) | 1895 (62.3) |
| Family history | ||
| No or unknown family history | 4525 (48.7) | 2146 (68.3) |
| Positive family history | 4772 (51.3) | 996 (31.7) |
| Allergy | ||
| No allergy | 5542 (58.9) | 932 (29.7) |
| ≥1 allergy | 3755 (39.9) | 1651 (52.5) |
| Missing data | 105 (1.1) | 559 (17.8) |
| Hyperreactivity | ||
| No hyperreactivity | 3105 (33.4) | 2347 (74.7) |
| Hyperreactivity present | 6192 (66.6) | 795 (25.3) |
| Occupational risk | ||
| No occupational risk | 8742 (94.0) | Unknown |
| Occupational risk present | 555 (6.0) | |
| Age years | 53.3±17.1 | 49.4±16.8 |
| Age of onset years | 35.4±23.3 | 36.1±21.6 |
| Total ACQ score | 1.2±0.9 | 1.3±0.9 |
| Total CCQ score | 1.4±0.9 | 1.5±0.9 |
| Lung function post bronchodilator | ||
| FEV1 L | 2.9±1.0 | 2.9±1.0 |
| FEV1 % predicted | 89.4±19.3 | 92.1±20.0 |
| FVC L | 3.9±1.1 | 4.0±1.1 |
| FVC % predicted | 101.6±16.5 | 106.7±35.9 |
| FEV1/FVC | 73.0±12.9 | 72.1±13.6 |
| Reversibility % | 6.1±7.5 | 6.9±9.0 |
Data are presented as n, n (%) or mean±sd. COPD: chronic obstructive pulmonary disease; ACOS: asthma–COPD overlap syndrome; ACQ: Asthma Control Questionnaire; CCQ: Clinical COPD Questionnaire; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity. #: database from the asthma/COPD service used for development of the decision tree (Groningen, the Netherlands); ¶: database from the asthma/COPD service used in the external validation (Rotterdam, the Netherlands); +: total diagnosed was 3141 because one patient could not perform a proper lung function test.