Clinical course and outcome for critically ill children with Down syndrome: a retrospective cohort study.

PURPOSE: Children with Down syndrome (DS) have several genetic anomalies within chromosome 21 which may influence their response to critical illness. We compared the intensive care course and outcome of children with DS versus those without.
METHODS: Retrospective cohort study in four English paediatric intensive care units (ICUs) (2003-2009, n = 33,485). We examined, via a competing risks model, whether risk (subhazard) for ICU mortality differed for children with DS, after adjusting for important confounders.
RESULTS: DS patients exhibited lower disease severity at ICU admission but subsequently required a higher proportion of cardiovascular support, and similar renal support to non-DS patients. Children with DS (n = 1,278) had lower crude mortality than those without (4.2 versus 6.2 %, p = 0.003). This was not significant when expressed as standardized mortality ratio: 0.83 [95 % confidence interval (CI) 0.63-1.09] versus 0.90 (95 % CI 0.86-0.94). However, the competing risks model showed that mortality risk was influenced by length of ICU stay. At admission, DS patients exhibited a subhazard for mortality of 0.63 (95 % CI 0.46-0.85), which increased to 1.00 by day 10 of admission, and continued rising above that of non-DS children thereafter.
CONCLUSIONS: Children with DS require a higher proportion of organ support than expected by disease severity at ICU admission. In addition, the mortality risk for children with DS is dependent upon length of ICU stay. These findings could reflect differences in case mix, but are also compatible with different response to critical illness in this group.