A case-control study of necrotising enterocolitis in very low birth weight neonates at a tertiary hospital in South Africa.

Between January 2018 to June 2020, 119 of 1,106 Very Low Birth Weight (VLBW) neonates admitted to Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) were diagnosed with Necrotising Enterocolitis (NEC), representing 10.8% of the VLBW neonates. This retrospective matched case-control study (119 cases, 119 controls; matched 1:1 on birthweight ±100 g, gestational age ±2 weeks, and postnatal age ±1 week) aimed to determine the prevalence, risk factors, and outcomes of NEC in VLBW neonates at a tertiary hospital in South Africa. We handled missing data using Multiple Imputation by Chained Equations (MICE, M = 20) after confirming the data were Missing at Random. We used MI-pooled conditional logistic regression for all analyses to account for the matched design. The mortality rate among NEC cases was 49.6%. On univariate analysis, outborn status (cOR 3.69, 95% CI 1.84-7.43), conventional ventilation (cOR 4.73, 95% CI 2.52-8.88), late-onset sepsis (cOR 6.29, 95% CI 3.02-13.07), and fungal sepsis (cOR 6.50, 95% CI 2.27-18.62) were significantly associated with NEC. In the multivariable analysis, conventional ventilation (acOR 3.37, 95% CI 1.42-8.01, p = 0.006) and late-onset sepsis (acOR 5.27, 95% CI 1.84-15.06, p = 0.002) were independently associated with NEC. The final model demonstrated excellent discrimination (AUC = 0.827). Maternal factors were not independently associated with NEC. The prevalence and mortality of NEC among VLBW neonates remain high in this tertiary setting; this aligns with previous studies from the region. Late-onset sepsis and conventional ventilation were the strongest independent risk factors, highlighting the importance of stringent infection prevention and early recognition of clinical deterioration.