Table 1. Clinical characteristics of the study cohort (N = 844) overall and within groups paired using the PSM method (N = 286).
| Characteristics | All infants | Propensity-matched infants | ||||
|---|---|---|---|---|---|---|
| Early caffeine | Late caffeine | P value | Early caffeine | Late caffeine | P value | |
| N = 676 | N = 168 | N = 143 | N = 143 | |||
| GA, weeks | ||||||
| Mean ±SD | 28.2 ±2.2 | 28.5 ±2.4 | 0.0680 | 28.6 ±2.1 | 28.5 ±2.4 | 0.9618 |
| Median (IQR) | 28 (27–30) | 29 (27–30) | 29 (27–30) | 29 (27–30) | ||
| Birth weight, g | ||||||
| Mean ±SD | 1118 ±357 | 1155 ±404 | 0.4397 | 1174 ±357 | 1168 ±406 | 0.8190 |
| Median (IQR) | 1090 (840–1345) | 1100 (845–1455) | 1130 (895–1450) | 1100 (850–1485) | ||
| Sex | ||||||
| Male, n (%) | 364 (54.3) | 88 (53.0) | 0.8277 | 77 (53.8) | 76 (53.8) | 1.0000 |
| Place of birth | ||||||
| Inborn, n(%) | 576 (88.9) | 147 (90.7) | 0.5899 | 129 (90.2) | 133 (93.0) | 0.5223 |
| Outborn, n(%) | 72 (11.1) | 15 (9.3) | 14 (9.8) | 10 (7.0) | ||
| Mode of delivery | ||||||
| C-section, n(%) | 533 (79.6) | 134 (80.7) | 0.8194 | 111 (77.6) | 115 (80.4) | 0.6631 |
| Vaginal birth, n(%) | 137 (20.4) | 32 (19.3) | 32 (22.4) | 28 (19.6) | ||
| Apgar at 5 min. | ||||||
| Mean ±SD | 6.5 ±1.9 | 6.5 ±2.3 | 0.6388 | 6.6 ±2.1 | 6.5 ±6.5 | 0.9543 |
| Median (IQR) | 7 (6–8) | 7 (6–8) | 7 (6–8) | 7 (6–8) | ||
| Antenatal steroid use | ||||||
| N (%)# | 550 (82.3) | 118 (71.5) | 0.0026 | 106 (74.1) | 106 (74.1) | 1.0000 |
| Intubation in the DR | ||||||
| N (%) | 349 (52.2) | 91 (54.2) | 0.7058 | 76 (53.1) | 77 (53.8) | 1.0000 |
| Caffeine therapy, days | ||||||
| Mean ±SD | 37.8 ±23.3 | 24.8 ±19.3 | 0.0000 | 35.1 ±25 | 24.3 ±19.7 | 0.0000 |
| Median (IQR) | 35 (20–52) | 21.5 (9.8–36) | 31 (19–48) | 21 (9–35) | ||
# data on antenatal steroids were unavailable for 11 neonates, including 8 infants in early caffeine and 3 infants in late caffeine groups.