Table 4.
Methods comparison (Bland-Altman statistics) for lung function measurements performed in a GP’s office and at lung function lab (N = 227)
| COPD-6™ at GP’s office | |||||
|---|---|---|---|---|---|
| Lung function lab measurements | FEV1 (L) | FEV6 (L) | FEV1/FEV6 (%) | ||
| COPD-6™ | FEV1 (L) | Δ (95 % CI) | 0.01 (−0.05 to 0.03) | NA | NA |
| FEV6 (L) | Δ (95 % CI) | NA | −0.17 (−0.24 to −0.12)* | NA | |
| FEV1/FEV6 (%) | Δ (95 % CI) | NA | NA | 4.83 (3.71 to 6.35)* | |
| Spirometry | FEV1 (L) | Δ (95 % CI) | −0.12 (−0.15 to −0.09)* | NA | NA |
| FVC (L) | Δ (95 % CI) | NA | −0.66 (−0.72 to -0.59)* | NA | |
| FEV1/FVC (%) | Δ (95 % CI) | NA | NA | 10.24 (9.32 to 11.26)* | |
| Post-bronchodilator spirometry | FEV1 (L) | Δ (95 % CI) | −0.15 (−0.19 to −0.12)* | NA | NA |
| FVC (L) | Δ (95 % CI) | NA | −0.60 (−0.65 to −0.54)* | NA | |
| FEV1/FVC (%) | Δ (95 % CI) | NA | NA | 8.52 (7.57 to 9.47)* | |
GP general practitioner, FEV 1 forced expiratory volume in 1 s, FEV 6 forced expiratory volume in 6 s, FVC forced expiratory volume, FVC forced expiratory volume, Δ mean difference of the index test (COPD-6™ measurement at GP’s office) from the reference (tertiary care measurement), 95 % CI 95 % confidence interval
NA not applicable
*P < 0.001