Table 3.
Characteristics of patients included in model derivation and external validation
| Indicator | Levels | Derivation | Temporal validationa | Model updating (recalibration)b | External validation | ||||
|---|---|---|---|---|---|---|---|---|---|
| SENSSc, n = 5427 | NETSd, n = 4840 | SENSSc, n = 1627 | NETSd, n = 1443 | SENSSc, n = 8848 | NETSd, n = 6610 | SENSSc, n = 53,909 | NETSd, n = 45,090 | ||
| n (%) | n (%) | n (%) | n (%) | n (%) | n (%) | n (%) | n (%) | ||
| Male | Yes | 2937 (54.12) | 2605 (53.82) | 961 (59.07) | 850 (58.91) | 4963 (56.09) | 3713 (56.17) | 29,384 (54.51) | 24,719 (54.82) |
| Missing | 13 (0.24) | 12 (0.25) | 2 (0.12) | 2 (0.14) | 27 (0.31) | 25 (0.38) | 642 (1.19) | 468 (1.04) | |
| Weight | 1000 g and below (ELBW) | 32 (0.59) | 31 (0.64) | 10 (0.61) | 10 (0.69) | 104 (1.18) | 96 (1.45) | 1243 (2.31) | 1083 (2.4) |
| 1001–1499 g (VLBW) | 136 (2.51) | 115 (2.38) | 45 (2.77) | 40 (2.77) | 379 (4.28) | 366 (5.54) | 3844 (7.13) | 3494 (7.75) | |
| 1500–2499 g (LBW) | 1180 (21.74) | 1043 (21.55) | 361 (22.19) | 316 (21.9) | 2123 (23.99) | 1717 (25.98) | 13,207 (24.5) | 11,320 (25.11) | |
| 2500–4000 g (NBW) | 3841 (70.78) | 3438 (71.03) | 1125 (69.15) | 1002 (69.44) | 5834 (65.94) | 4162 (62.97) | 31,285 (58.03) | 25,932 (57.51) | |
| > 4000 g (macrosomia) | 229 (4.22) | 204 (4.21) | 85 (5.22) | 74 (5.13) | 368 (4.16) | 243 (3.68) | 3352 (6.22) | 2478 (5.5) | |
| Missing | 9 (0.17) | 9 (0.19) | 1 (0.06) | 1 (0.07) | 40 (0.45) | 26 (0.39) | 978 (1.81) | 783 (1.74) | |
| Mode of delivery | Breech | 43 (0.79) | 40 (0.83) | 23 (1.41) | 19 (1.32) | 197 (2.23) | 165 (2.5) | 1226 (2.27) | 1028 (2.28) |
| Caesarean section (C/S) | 2212 (40.76) | 1957 (40.43) | 574 (35.28) | 509 (35.27) | 3211 (36.29) | 2251 (34.05) | 18,634 (34.57) | 15,540 (34.46) | |
| Spontaneous vaginal (SVD)e | 3014 (55.54) | 2698 (55.74) | 1012 (62.2) | 897 (62.16) | 5157 (58.28) | 4006 (60.61) | 33,203 (61.59) | 27,824 (61.71) | |
| Missing | 158 (2.91) | 145 (3) | 18 (1.11) | 18 (1.25) | 283 (3.2) | 188 (2.84) | 846 (1.57) | 698 (1.55) | |
| Outbornf | Yes | 123 (2.27) | 107 (2.21) | 60 (3.69) | 57 (3.95) | 495 (5.59) | 439 (6.64) | 6017 (11.16) | 5155 (11.43) |
| Missing | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | |
| Apgar score (5 min) | 0–3 | 116 (2.14) | 112 (2.31) | 33 (2.03) | 33 (2.29) | 293 (3.31) | 274 (4.15) | 1146 (2.13) | 1005 (2.23) |
| 4–6 | 602 (11.09) | 593 (12.25) | 200 (12.29) | 199 (13.79) | 1334 (15.08) | 1184 (17.91) | 9121 (16.92) | 7986 (17.71) | |
| 7–10 | 3992 (73.56) | 3918 (80.95) | 1149 (70.62) | 1142 (79.14) | 6484 (73.28) | 4868 (73.65) | 38,391 (71.21) | 31,531 (69.93) | |
| Missing | 717 (13.21) | 217 (4.48) | 245 (15.06) | 69 (4.78) | 737 (8.33) | 284 (4.3) | 5251 (9.74) | 4568 (10.13) | |
| HIV exposure | Exposed | 319 (5.88) | 287 (5.93) | 84 (5.16) | 74 (5.13) | 473 (5.35) | 439 (6.64) | 2145 (3.98) | 1957 (4.34) |
| Missing | 305 (5.62) | 277 (5.72) | 94 (5.78) | 80 (5.54) | 276 (3.12) | 219 (3.31) | 4742 (8.8) | 3826 (8.49) | |
| Outcome | Aliveg | 4900 (90.29) | 4374 (90.37) | 1469 (90.29) | 1299 (90.02) | 8134 (91.93) | 5950 (90.02) | 46,358 (85.99) | 38,576 (85.55) |
| Dead | 508 (9.36) | 447 (9.24) | 152 (9.34) | 138 (9.56) | 696 (7.87) | 649 (9.82) | 7486 (13.89) | 6482 (14.38) | |
| Missing | 19 (0.35) | 19 (0.39) | 6 (0.37) | 6 (0.42) | 18 (0.2) | 11 (0.17) | 65 (0.12) | 32 (0.07) | |
aThe same hospital was used at the model derivation and temporal validation stage, with the temporal validation stage using data from a specific future period
bData is only from the same hospital used at derivation and temporal validation stage. Data collected between January 2016 and December 2020
cData presented are before multiple imputation. The multiple imputation filled in the missing values while preserving the pattern of distribution observed in the original datasets
dAll cases included in NETS model are subset of those included in SENSS model but with a treatment sheet present; given the models are developed independently of each other, there is no substantive implication on interpretation of findings
eIncludes assisted vaginal deliveries (e.g. forceps, vacuum)
fOutborn refers to neonates admitted to the unit having been born either in another facility, at home or on the way to hospital
gPatients referred out of hospital recoded were also treated as being ‘alive’ at discharge