Assessing neonatal Sequential Organ Failure (nSOFA) scores in suspected late-onset neonatal sepsis among preterm infants: implications for morbidity and mortality

Abstract

Background: The neonatal Sequential Organ Failure Assessment (nSOFA) score is an organ dysfunction score developed for predicting mortality risk in preterm neonates with proven late-onset neonatal sepsis (LONS) and necrotising enterocolitis. However, the utility of the nSOFA score in determining the risk of retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD) or mortality in patients with suspected LONS is unknown.

Methods: We performed a dual-centre retrospective cohort study of preterm (gestational age <32 weeks) neonates suspected of LONS, from 2016 to 2020 at two neonatal intensive care units. The nSOFA scores (range 0-15) were calculated for each suspected LONS episode at various time points around the sepsis evaluation. A nSOFA burden score was calculated, by counting each time point the nSOFA score was ≥4 during all sepsis episodes (in the time period -6 to 48 hours). The association with 10-day sepsis-related mortality and severe ROP and BPD was assessed.

Results: A total of 1157 episodes of suspected LONS in 706 neonates occurred. The nSOFA was significantly associated with 10-day mortality at various time points. The nSOFA score 6 hours after drawing a blood culture (T6) was associated with 10-day sepsis-related mortality (adjusted OR (aOR) 1.31; 95% CI (1.22 to 1.40; p<0.001)), in a model corrected for gestational age, sex, age at evaluation and gestational age-adjusted birth weight. The nSOFA burden scores were positively associated with the risk for ROP (aOR 1.24; 95% CI 1.09 to 1.41; p=0.001) and BPD (aOR 1.30; 95% CI 1.13 to 1.50; p<0.001).

Conclusion: Our findings show that the nSOFA score in preterm neonates suspected of LONS is associated with subsequent mortality, ROP and BPD. Incorporating nSOFA scores may help to identify sepsis survivors at the highest risk of adverse outcomes, who may require more intensive monitoring and adapted therapy.

Keywords: Neonatology.

Figure 1. Boxplot of the nSOFA values for survivors and non-survivors at different time points relative to sepsis evaluation. *p<0.001 (A). Area under receiver operating characteristic curve for 10-day mortality at T0, T6 and T12 time points (B).

Figure 2. Boxplot for nSOFA component values for survivors and non-survivors at different time points relative to sepsis evaluation. (A) respiratory (B) cardiovascular (C) haematological. nSOFA, neonatal Sequential Organ Failure Assessment.

Figure 3. Boxplot of the nSOFA burden score for patients that required laser for ROP and who did not (A) and the nSOFA burden score for patients with severe BPD (B). BPD, bronchopulmonary dysplasia; nSOFA, neonatal Sequential Organ Failure Assessment; ROP, retinopathy of prematurity.