Spirometry variables at 8 and 18 years comparing preterm and control groups
| 8 years | 18 years | |||||
|---|---|---|---|---|---|---|
| Variable | Preterm n=240 | Control n=208 | Mean difference (95% CI) | Preterm n=209 | Control n=154 | Mean difference (95% CI) |
| FEV1 | ||||||
| z-score | −0.93 (1.07) | 0.08 (1.01) | −1.02 (−1.21 to −0.82) p<0.001 | −1.03 (1.08)* | −0.10 (1.03)* | −0.92 (−1.14 to −0.71) p<0.001 |
| % predicted | 88.8 (12.8) | 100.9 (11.8) | −12.0 (−14.3 to −9.7) p<0.001 | 87.9 (12.9)* | 98.7 (10.7)* | −10.9 (−13.4 to −8.4) p<0.001 |
| FVC | ||||||
| z-score | −0.88 (1.20) | −0.21 (1.06) | −0.67 (−0.88 to −0.46) p<0.001 | −0.48 (1.03) | −0.09 (0.87) | −0.38 (−0.58 to −0.18) p<0.001 |
| % predicted | 89.6 (14.1) | 97.5 (12.6) | −7.9 (−10.4 to −9.4) p<0.001 | 94.4 (12.1) | 99.0 (10.4) | −4.5 (−6.9 to −2.1) p<0.001 |
| FEV1/FVC | ||||||
| z-score | 0.10 (1.51) | 0.64 (1.20) | −0.55 (−0.80 to −0.29) p<0.001 | −0.85 (1.25)* | −0.06 (0.97)* | −0.80 (−1.03 to −0.56) p<0.001 |
| % | 88.4 (9.2) | 91.4 (6.6) | −3.0 (−4.5 to −1.5) p<0.001 | 81.5 (9.5)* | 87.0 (6.3)* | −5.5 (−7.2 to −3.7) p<0.001 |
| FEF25%–75% | ||||||
| z-score | −1.35 (1.10)† | −0.38 (1.10)* | −0.96 (−1.16 to −0.77) p<0.001 | −1.37 (1.19) | −0.23 (0.98) | −1.14 (−1.37 to −0.90) p<0.001 |
| % predicted | 71.4 (23.3)† | 92.1 (21.6)* | −20.7 (−24.9 to −16.4) p<0.001 | 73.1 (22.9) | 95.9 (21.4) | −22.7 (−27.4 to −18.1) p<0.001 |
| FEF75% | ||||||
| z-score | −0.61 (1.16)‡ | 0.09 (1.02)§ | −0.70 (−0.91 to −0.49) p<0.001 | −0.95 (1.14)* | 0.05 (0.87)* | −1.00 (−1.21 to −0.78) p<0.001 |
| % predicted | 85.5 (35.8)‡ | 106.7 (34.2)§ | −21.2 (−28.0 to −14.5) p<0.001 | 76.4 (30.8)* | 104.7 (29.7)* | −28.3 (−34.6 to −21.9) p<0.001 |
*n=1 missing data.
†n=7 missing data.
‡n=19 missing data.
§n=10 missing data.
FEF25%–75%, forced expiratory flow at 25%–75% of FVC; FEF75%, forced expiratory flow at 75% of FVC expired.