Table 2 Data items reported in more than 20% of studies and stratified by the age of the study participants
| Â | Infant age | Â | ||||||
|---|---|---|---|---|---|---|---|---|
Preterm studies (n = 29) | Term studies (n = 6) | Mixed-ages studies (n = 9) | All studies (n = 44) | |||||
Baseline Characteristics | ||||||||
 Gestational age | 29 | (100%) | 4 | (67%) | 9 | (100%) | 42 | (96%) |
 Sex | 29 | (100%) | 6 | (100%) | 6 | (67%) | 41 | (93%) |
 Birth weight | 29 | (100%) | 5 | (83%) | 6 | (67%) | 40 | (91%) |
 Antenatal steroids | 25 | (86%) | 1 | (17%) | 1 | (11%) | 27 | (61%) |
 Multiple births | 21 | (72%) | 1 | (17%) | 2 | (22%) | 24 | (55%) |
 Respiratory support | 17 | (59%) | 3 | (50%) | 3 | (33%) | 23 | (52%) |
 Mode of delivery | 14 | (48%) | 2 | (33%) | 5 | (56%) | 21 | (48%) |
 Infection | 15 | (52%) | 3 | (50%) | 3 | (33%) | 21 | (48%) |
 Drug treatment | 15 | (52%) | 0 | (0%) | 5 | (56%) | 20 | (45%) |
 Maternal ethnicity | 15 | (52%) | 1 | (17%) | 3 | (33%) | 19 | (43%) |
 Apgar score 5 min | 14 | (48%) | 0 | (0%) | 5 | (56%) | 19 | (43%) |
 Age | 11 | (38%) | 6 | (100%) | 2 | (22%) | 19 | (43%) |
 Inborn | 13 | (45%) | 0 | (0%) | 2 | (22%) | 15 | (34%) |
 Maternal age | 6 | (21%) | 1 | (17%) | 6 | (67%) | 13 | (30%) |
Stratification items | ||||||||
 Neonatal unit identifier | 22 | (76%) | 1 | (17%) | 2 | (22%) | 25 | (57%) |
 Gestational age | 14 | (48%) | 1 | (17%) | 3 | (33%) | 17 | (39%) |
Primary outcome adjusting items | ||||||||
 Gestational age | 17 | (59%) | 1 | (8%) | 1 | (11%) | 19 | (43%) |
 Neonatal unit identifier | 10 | (34%) | 1 | (8%) | 2 | (22%) | 13 | (28%) |
 Birth weight | 9 | (31%) | 0 | (0%) | 1 | (11%) | 10 | (22%) |