Social determinants of health and outcome of extremely preterm infants: A Swiss population-based study

BACKGROUND AND AIMS: Social determinants of health (SDoH) are associated with the outcome of preterm infants, but data in Switzerland are lacking. The aim of this study was to assess the associations of maternal nationality, parental socioeconomic status (SES) and language, with perinatal and 18-month-old outcomes of extremely preterm infants in Switzerland. METHODS: Surviving extremely preterm infants born in our tertiary care neonatal centre between 2009-2020 were evaluated at the age of 18 corrected months using Bayley Scales of Infant Development, and neurological examination. We analyzed differences in outcomes according to maternal nationality, socioeconomic status and language. RESULTS: In the neonatal period, among 408 (46% female) patients (median 26 6/7 weeks (25 4/7-27 2/7)), median birthweight 790g (669-942g), nationality was associated with the rate of multiplets, (34% in Swiss vs 27% for European, 14% extra-European, p = .012). Parental SES was associated with the rate of multiplets, (45%, mid SES 28%, low SES 19%, p < 0.001), with having oxygen at 36 weeks (high SES 32%, mid SES 56%, low SES 19%, p = .01), and with the rate of feeding with mother's own milk (high SES 80%, mid SES 67%, low SES 42%, p < .001). Parental language was not associated with neonatal outcomes. At 18 months, the rate of neurodevelopmental impairment was similar across the 3 SDoH, but the median cognitive score was significantly higher in Swiss than in extra-European patients (100(95-115) vs 90(85-100), p = .002), and in middle SES compared to low SES patients (100(95-110) vs 95(85-100), p = .031). The median cognitive (100(90-111) vs 95(85-100), p = .009) and language scores (91(83-103) vs 86(77-94), p = .002) of children of French speaking families were higher than non-French speaking families. CONCLUSION: Maternal nationality, parental SES and parental language were minimally associated with perinatal outcomes of EPT infants. However, these 3 SDoH were significantly associated with neurodevelopmental outcomes at 18 months.