Risk adjusted and population based studies of the outcome for high risk infants in Scotland and Australia

Objectives-To compare outcomes of care in selected neonatal intensive care units (NICUs) for very low birthweight (VLBW) or preterm infants in Scotlan d and Australia (study 1) and perinatal care for all VLBW infants in both c ountries (study 2). Design-Study 1: risk adjusted cohort study; study 2: population based cohor t study. Subjects-Study 1: all 2621 infants of < 1500 g birth weight or < 31 weeks' gestation admitted to a volunteer sample of hospitals comprising eight of a ll 17 Scottish NICUs and six of all 12 tertiary NICUs in New South Wales an d Queensland in 1993-1994; study 2: all 5986 infants of 500-1499 g birth we ight registered as live born in Scotland and Australia in 1993-1994. Main outcomes-Study 1: (a) hospital death; (b) death or cerebral damage, ea ch adjusted for gestation and CRIB (clinical risk index for babies); study 2: neonatal (28 day) mortality. Results-Study 1. Data were obtained for 1628 admissions in six Australian N ICUs, 775 in five Scottish tertiary NICUs, and 148 in three Scottish non-te rtiary NICUs. Crude hospital death rates were 13%, 22%, and 22% respectivel y. Risk adjusted hospital mortality was about 50% higher in Scottish than i n Australian NICUs (adjusted mortality ratio 1.46, 95% confidence interval (CI) 1.29 to 1.63, p < 0.001). There was no difference in risk adjusted out comes between Scottish tertiary and nontertiary NICUs, After risk adjustmen t, death or cerebral damage was more common in Scottish than Australian NIC Us (odds ratio 1.9, 95% CI 1.5 to 2.5). Both these risk adjusted adverse ou tcomes remained more common in Scottish than Australian NICUs after excludi ng all infants < 28 weeks' gestation from the comparison. Study 2. Populati on based neonatal mortality in infants of 500-1499 g was higher in Scotland (20.3%) than Australia (16.6%) (relative risk 1.22, 95% CI 1.08 to 1.39, p = 0.002). In a post hoc analysis, neonatal mortality was also higher in En gland and Wales than in Australia. Conclusions-Study 1: outcome was better in the Australian NICUs. Study 2: p erinatal outcome was better in Australia. Both results may be consistent, a t least in part, with differences in the organisation and implementation of neonatal care.