Table 1.
Cohort characteristics and potential determinants of the outcomes
| Cohort 1 (n = 56), mean (SD) | Cohort 2 (n = 56), mean (SD) | Mean difference (C2−C1) | 95% CI | |
|---|---|---|---|---|
| Patient characteristics | ||||
| Gestational age in weeksa | 29.3 (2.2) | 29.6 (1.8) | 0.3 | −0.4 to 1.1 |
| Birthweight in gramsa | 1124 (290) | 1153 (330) | 29 | −87 to 146 |
| Head circumference of week 1 in cm | 26.5 (2.2) | 26.7 (1.8) | −0.3 | −1.1 to 0.6 |
| Days of mechanical ventilationa | 3.8 (4.3) | 2.4 (3.5) | −1.4 | −2.9 to 0.1 |
| Nutritional intake | ||||
| Protein week 1 (g/kg/week) | 14.7 (3.4) | 18.0 (3.6) | 3.3 | 2.0 to 4.6 |
| Protein week 2 (g/kg/week) | 21.1 (5.0) | 22.8 (4.8) | 1.8 | −0.1 to 3.6 |
| Energy week 1 (kcal/kg/week) | 513 (94) | 605 (111) | 92 | 54 to 131 |
| Energy week 2 (kcal/kg/week) | 710 (173) | 777 (165) | 68 | 5 to 131 |
| Cohort 1 (n = 56), number (%) | Cohort 2 (n = 56), number (%) | OR (C1 versus C2) | 95% CI | |
|---|---|---|---|---|
| Potential determinants of the outcomes | ||||
| Gender, femalea | 32 (57) | 27 (48) | 1.4 | 0.7 to 3.0 |
| IUGR | 9 (16) | 11 (20) | 0.8 | 0.3 to 2.1 |
| IRDSa | 38 (68) | 33 (59) | 1.5 | 0.7 to 3.2 |
| CLD | 10 (18) | 6 (11) | 1.8 | 0.6 to 5.4 |
| PDA | 28 (50) | 17 (30) | 2.3 | 1.1 to 5.0 |
| PDA treatmenta | 25 (45) | 12 (21) | 3.0 | 1.3 to 6.8 |
| LOSa | 26 (46) | 26 (46) | 1.0 | 0.5 to 2.1 |
| NEC > 1b | 3 (5) | 5 (9) | 0.6 | 0.1 to 2.5 |
| IVH grade 3/4 | 3 (5) | 1 (2) | 3.1 | 0.3 to 30.9 |
| Maternal educationa low/high (missing) | 10/37 (9) | 8/37 (11) | 1.3 | 0.4 to 3.5 |
C1 = Cohort 1; C2 = Cohort 2; OR = Odds ratio; 95% CI = 95% Confidence interval; IUGR = Intra‐uterine growth retardation defined as a birthweight < 10th percentile; IRDS = Infant respiratory distress syndrome; CLD = Chronic lung disease defined as supplemental oxygen for >28 days; PDA = Patent ductus arteriosus diagnosed by echocardiography; PDA treatment = Including up to three courses of indomethacin and, or, surgical ligation; LOS = Late‐onset sepsis defined by positive blood culture and clinical signs of infection occurring more than 72 hours after birth; NEC = Necrotising enterocolitis defined by Bell's stage > 1b; IVH = Intraventricular haemorrhage; Low maternal education = ≤10 years of education.
Included in potential confounder set in multivariable analyses (IUGR, CLD and PDA not included because of large overlap with other variables and NEC and IVH not included because of small numbers).