Table 6.
Sensitivity analysis comparing lung function, the prevalence of any chest sign, and the sensitivity, specificity, and likelihood ratio of any chest sign for COPD in practices where patients were examined before spirometry and after spirometry
| n | Any chest sign, n (%) | COPD (FEV1/FVC < 0.7), n (%) | Sensitivity | Specificity | Likelihood ratio (95% CI) | |||
|---|---|---|---|---|---|---|---|---|
| Patients examined before spirometry (4 GP offices) | ||||||||
| Evaluated against prebronchodilator spirometry | 211 | 72 | 34.1a | 98 | 46.4b | 53.1 | 82.3 | 3.0 (1.9–4.7) |
| Evaluated against postbronchodilator spirometry | 211 | 72 | 34.1 | 94 | 44.5c | 56.7 | 83.8 | 3.5 (2.2–5.4) |
| Patients examined after spirometry (3 GP offices) | 164 | 73 | 44.5 | 55 | 33.5 | 61.8 | 64.2 | 1.7 (1.2–2.4) |
Notes:
The difference between the subgroups examined before and after spirometry was statistically significant, P = 0.04
the difference between the subgroups examined before and after spirometry was statistically significant, P = 0.01
the difference between the subgroups examined before and after spirometry was statistically significant, P = 0.03.
Abbreviations: COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; CI, confidence interval; GP, General Practitioner.