Table 2 Missingness among the matching variables
Variable | HES 1995 | EPICure (1995) | HES 2006 | EPICure-2 (2006) |
|---|---|---|---|---|
Missing (%) | Missing (%) | Missing (%) | Missing (%) | |
Date of birth | 8807 (1.53) | 0 (0.00) | 4265 (0.68) | 0 (0.00) |
GA at birth | 164006 (28.50) | 0 (0.00) | 336178 (53.23) | 7 (0.25) |
Sex | 2616 (0.45) | 0 (0.00) | 3202 (0.51) | 9 (0.33) |
Discharge date | 16912 (2.94) | 373 (55.84) | — | — |
Date of death | 571417 (99.29) | 268 (40.12) | — | — |
Birth weight | 152641 (26.52) | 0 (0.00) | 288014 (45.61) | 26 (0.95) |
Birth order | 250718 (43.56) | 0 (0.00) | 224632 (35.57) | 0 (0.00) |
Delivery method | 168018 (29.19) | 1 (0.15) | — | — |
Number.of babies | 152378 (26.48) | 0 (0.00) | 209455 (33.17) | 0 (0.00) |
Previous pregnancies number | — | — | 618692 (97.97) | 101 (3.67) |
Ethnic category | 462999 (80.45) | 0 (0.00) | — | — |
Postcode | — | — | 290462 (46.00) | 1 (0.04) |
Mother’s dob | — | — | 273426 (43.30) | 2750 (100.00) |
Mother’s age at delivery | 214999 (37.36) | 4 (0.60) | 273430 (43.30) | 8 (0.29) |