Table 2.
Changes in study parameters through the follow-up period
| Baseline | 6 months | 12 months | Effect size | p-value** baseline vs 6 months | p-value** 6 vs 12 months | p-value** baseline vs 12 months | |
|---|---|---|---|---|---|---|---|
| PO2, median (IQR) | 58.0 (54.0–59.0) | 62 (58–68) | 63 (58–67) | 0.39 | <0.001 | 0.919 | <0.001 |
| PCO2, median (IQR) | 52.9 (50.0–55.0) | 46 (43–50) | 45 (43–48) | 0.67 | <0.001 | 0.663 | <0.001 |
| pH, median (IQR) | 7.41 (7.39–7.41) | 7.42 (7.40–7.43) | 7.41 (7.40–7.42) | 0.25 | <0.001 | 0.266 | 0.021 |
| FEV1, median (IQR) | 30.0 (27.0–46.0) | 38 (25–52) | 33 (26–50) | 0.15 | 0.013 | 0.439 | 0.652 |
| FVC, mean (SD) | 49.6 (15.1) | 53.5 (17.7) | 54.6 (16.5) | 0.14 | 0.071 | 1.000 | 0.028 |
| FEV1/FVC, mean (SD) | 56.0 (9.9) | 55.1 (11.5) | 53.6 (11.5) | 0.15 | 1.000 | 0.180 | 0.115 |
| MRC, mean (SD) | 2.79 (0.92) | 2.51 (0.98) | 2.50 (1.07) | 0.11 | 0.009 | 0.672 | <0.001 |
| BMI, mean (SD) | 28.5 (5.4) | 29.3 (5.6) | 28.9 (5.6) | 0.07 | 0.062 | 0.760 | 1.000 |
| 6MWT, mean (SD) | 247.5 (106.8) | 268.9 (114.6) | 254.2 (134.9) | 0.11 | 0.049 | 0.420 | 1.000 |
| BODE, mean (SD) | 5.8 (2.2) | 4.8 (2.4) | 5.2 (2.7) | 0.32 | <0.001 | 0.143 | 0.113 |
| EXACERB, median (IQR) | 1 (1–2) | 0 (0–1) | 0 (0–1) | 0.39 | <0.001 | 0.196 | <0.001 |
| CAT, mean (SD) | 18.7 (6.9) | 16.2 (6.8) | 15.5 (8.4) | 0.22 | <0.001 | 0.499 | 0.001 |
Notes: Repeated measurements ANOVA. Effects reported include differences between the groups in the degree of change over the follow-up period.
**
Pairwise comparisons after Bonferroni correction. Log transformations were used in analysis. Bold values are statistically significant.
Abbreviations: 6MWT, 6 minute walk test; ANOVA, analysis of variance; CAT, COPD Assessment Test; EXACERB, exacerbations; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; IQR, interquartile range; MRC, Medical Research Council.