Table 2.
Bronchial obstruction in smokers with forced expiratory volume in one second (FEV1) <80% of predicted within different groups of symptoms
| Symptom
|
No of patients reporting symptom
|
No (%, 95% CI) of patients with FEV1 <80%
|
Odds ratio* (95% CI)
|
Negative predictive value (%)
|
|---|---|---|---|---|
| Family history: | ||||
| Asthma | 33 | 6 (18, 7 to 35) | 1.03 (0.38 to 2.77) | 82 |
| Allergy | 28 | 6 (21, 8 to 41) | 1.35 (0.49 to 3.70) | 83 |
| Symptom: | ||||
| Tiredness | 90 | 19 (21, 13 to 31) | 1.77 (0.77 to 4.06) | 87 |
| Chronic wheeze | 44 | 12 (27, 15 to 43) | 2.15 (0.94 to 4.88) | 85 |
| Chronic dyspnoea | 79 | 19 (24, 15 to 35) | 2.19 (0.98 to 4.90) | 87 |
| Chronic cough | 64 | 17 (27, 16 to 39) | 2.50 (1.14 to 5.52) | 87 |
| No of symptoms: | ||||
| 1 | 105 | 23 (22, 14 to 31) | 2.28 (0.93 to 5.60) | 89 |
| 2 | 59 | 17 (29, 18 to 42) | 3.02 (1.37 to 6.64) | 88 |
| 3 | 23 | 8 (35, 16 to 57) | 3.01 (1.17 to 7.70) | 85 |
*
Estimates of common odds ratio by Mantel-Haenszel test.