Risk factors for readmission for hyperbilirubinemia in neonates with ABO hemolytic disease: a single-center retrospective cohort study.

Objective: ABO hemolytic disease of the newborn (ABO-HDN) is a major risk factor for severe hyperbilirubinemia, a common readmission reason for newborns. In this study, we aimed to assess the risk factors for readmission associated with hyperbilirubinemia in neonates with ABO-HDN.
Methods: A retrospective cohort study was conducted including newborns with gestational age ≥35 weeks and ABO-HDN in 2018. Among 291 newborns, 36 were readmitted for hyperbilirubinemia and defined as the readmission group. The remaining 255 cases were used as a control group. We then performed between-group comparisons of clinical conditions associated with hyperbilirubinemia. Logistic regression was used to select risk predictors of readmission associated with hyperbilirubinemia due to ABO-HDN.
Results: Baseline characteristics were similar between both groups ( p  > .05, respectively). However, total serum bilirubin (TSB) before initiating phototherapy was significantly higher in the readmission group when compared with that in the control group at 0-24 h, 24-48 h, and 48-72 h (183.70 µmol/L [interquartile range (IQR) 161.18-196.48] vs. 150.35 µmol/L [IQR 131.73-175.38], p  = .005; 229.90 µmol/L [IQR 212.45-284.30] vs. 212.50 µmol/L [IQR 197.85-230.28], p  = .026; 268.10 µmol/L [IQR 257.70-279.05] vs. 249.50 µmol/L [IQR 236.80-268.70], p  = .045, respectively). The age of initiation of phototherapy in the readmission group was significantly lower than that in control group (30.0 h [IQR 18.0-49.00] vs. 42.0 h [IQR 23.0-61.0], p  = .012). The rate of rebound hyperbilirubinemia after the first phototherapy treatment was significantly higher in the readmission group compared to that in the control group (9 [25%] vs. 13 [5.1%], p  = .000), and the rate of positive direct antiglobulin testing was significantly higher than that in control group (17 [47.2%] vs. 74 [29.0%], p  = .027). Logistic regression analysis showed that the age of initiation of photography, TSB level before the first phototherapy, and rebound hyperbilirubinemia after first phototherapy were independent risk factors for readmission in newborns with hyperbilirubinemia associated with ABO-HDN.
Conclusions: Earlier age of phototherapy initiation, higher TSB levels at the time of initiating phototherapy and rebound hyperbilirubinemia after the first phototherapy treatment may increase the risk of readmission for hyperbilirubinemia in neonates with ABO-HDN. These factors should be considered in discharge planning and follow-up for newborns with ABO-HDN associated hyperbilirubinemia.