Characterization of “ICU-30”: A Binary Composite Outcome for Neonates With Critical Congenital Heart Disease

BACKGROUND: Neonates with heart disease requiring cardiopulmonary bypass surgery are at high risk for mortality and morbidity. As it is rare, short-term mortality is difficult to use as a primary outcome for clinical studies. We proposed “ICU-30” as a binary composite “poor” outcome consisting of: (1) mortality within 30 days, (2) intensive care unit (ICU) admission ≥30 days, or (3) ICU readmission before day 30. To measure the utility of this composite, we assessed its prognostic properties for 6-and 12-month mortality. METHODS AND RESULTS: This was a retrospective single-center cohort study of neonates requiring cardiopulmonary bypass between 2013 and 2020. Mortality among patients with and without the ICU-30 outcome was compared using log-rank tests and Cox regression. Areas under the receiver operating characteristic curves assessed the ability of the composite to predict 12-month mortality. In 887 neonates, 232 (26.2%) experienced the ICU-30 outcome, with more prolonged ICU stays and readmissions (both ≥9%) than 30-day mortality (4.2%). ICU-30 was associated with higher rates of 6-and 12-month mortality (log-rank P<0.001) and predicted 12-month mortality with area under the receiver operating characteristic of 0.81 (95% CI, 0.77–0.85). In 30-day survivors, both prolonged ICU stay (hazard ratio, 12.3; 95% CI, 6.70–22.7; P<0.001) and ICU readmission (hazard ratio, 2.99; 95% CI, 1.17–7.63; P=0.02) were associated with 12-month mortality. CONCLUSIONS: ICU-30, a composite outcome of mortality, ICU length of stay, or ICU readmission by 30 days was associated with 6-and 12-month mortality in neonates requiring cardiopulmonary bypass. ICU-30 is captured in routine data collection and appears to be a valid binary patient-centered outcome.