Purpose: We sought to describe changes in incidence and mortality of necrotizing enterocolitis (NEC) for very low birthweight (VLBW) infants in the United States over the past 12-years. Associated changes in management strategies were also evaluated. Methods: Data were prospectively collected on VLBW infants (≤1500g) born 2006 to 2017 and admitted to 820 US Vermont Oxford Network member centers. NEC was defined by the presence of at least one clinical and one radiographic finding. Surgical NEC was defined as receiving primary peritoneal drainage(PPD), laparotomy, or both. Risk ratios(RR) and 95% confidence intervals(CI) predicted mortality in 2017 compared to 2006 and were adjusted for birth weight, small for gestational age, and clustering of infants within hospitals. Results: Of 473,895 VLBW infants studied, 36,130(7.6%) were diagnosed with NEC of which 15,079 (41.7%) received surgery. The incidence of medical NEC decreased from 5.3% to 3.0%, and the incidence of surgical NEC decreased from 3.4% to 3.1%(Figure). Mortality among infants with medical NEC decreased from 20.7% to 16.8% (RR: 0.74; 95%CI:0.62, 0.87) while mortality for infants with surgical NEC decreased from 36.6% to 31.6% (RR: 0.84; 95%CI: 0.74, 0.95). Associated but not necessarily causative changes in management included the increased utilization of human milk at discharge (from 28.2% to 34.2%)(p < 0.001) and antenatal steroids(from 77.3% to 82.8%)(p < 0.001). Among infants with surgical NEC, the utilization of PPD increased(from 23.2% in 2006 to 47.3% in 2017) while laparotomy decreased(from 49.7% to 40.0%) over time. Mortality decreased in both groups (Any PPD: from 46.5% to 35.2%; Laparotomy only: 40.0% to 31.7%)(all changes p < 0.001). Conclusion:The incidence of both medical and surgical NEC has decreased over time. Survival amongst VLBW infants with medical and surgical NEC has also significantly improved. Changes in management during this time period included the increased utilization of human milk at discharge, antenatal steroids, and PPD.

Figure

Incidence of medical and surgical NEC over a 12-year period

Figure

Incidence of medical and surgical NEC over a 12-year period