Multivariable analyses: factors associated with repeated (2+) and single (1) admissions by anomaly or rare disease of congenital origin subgroup
| Factors | 2+ admissions | 1 admission | ||||
| Adjusted OR† | Adjusted OR† | |||||
| All | Isolated | Multiple | All | Isolated | Multiple | |
| Maternal age at delivery, years | ||||||
| ≤24 | 1.17 (1.06 to 1.30) | 1.22 (1.06 to 1.41) | 1.00 (0.89 to 1.12) | 1.04 (0.88 to 1.24) | ||
| 25–29 | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | ||
| 30–34 | 0.99 (0.89 to 1.10) | 0.94 (0.81 to 1.09) | 0.94 (0.83 to 1.06) | 0.90 (0.75 to 1.07) | ||
| ≥35 | 0.93 (0.82 to 1.04) | 0.54 (0.47 to 0.63) | 0.95 (0.83 to 1.09) | 0.58 (0.48 to 0.69) | ||
| Maternal smoking | ||||||
| Smoker | 1.20 (1.10 to 1.31) | 1.27 (1.13 to 1.41) | 1.06 (0.96 to 1.17) | 1.04 (0.92 to 1.18) | ||
| Non/ex-smoker | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | ||
| Infant sex* | ||||||
| Male | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
| Female | 0.84 (0.78 to 0.91) | 0.82 (0.74 to 0.90) | 0.90 (0.81 to 1.00) | 0.95 (0.87 to 1.04) | 1.01 (0.91 to 1.12) | 0.87 (0.77 to 0.99) |
| Gestational age,* weeks | ||||||
| <37 | 2.52 (2.25 to 2.83) | 2.83 (2.41 to 3.31) | 2.19 (1.90 to 2.53) | 1.68 (1.47 to 1.92) | 1.85 (1.55 to 2.21) | 1.50 (1.26 to 1.79) |
| ≥37 | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
*Variable identified for inclusion a priori.
†For ‘All’ anomaly subgroup, adjusted variables include maternal age at delivery, maternal smoking, infant sex and gestational age; for ‘isolate’ anomaly subgroup, adjusted variables include maternal smoking, infant sex and gestation age; for ‘multiple’ anomaly subgroup, adjusted variables include maternal age at delivery, infant sex and gestational age. Statistical significance at p<0.05.