Characteristics of patients who die of necrotizing enterocolitis

Abstract

Objective: Necrotizing enterocolitis (NEC) is associated with high morbidity and mortality among infants admitted for intensive care. The factors associated with mortality and catastrophic presentation remain poorly understood. Our objective was to describe the factors associated with mortality in infants with NEC and to quantify the degree to which catastrophic presentation contributes to mortality in infants with NEC. Catastrophic NEC was defined before data analysis as NEC that led to death within 7 days of diagnosis.

Study design: We performed a retrospective review of the Pediatrix's Clinical Data Warehouse (1997 to 2009, n=560,227) to compare the demographic, therapeutic and outcome characteristics of infants who survived NEC vs those who died. Associations were tested by bivariate and multivariate analysis.

Result: We compared the 5594 infants diagnosed with NEC and who were discharged home with 1505 infants diagnosed with NEC who died. In multivariate analysis, the factors associated with death (P<0.01 in analysis) were lower estimated gestational age, lower birth weight, treatment with assisted ventilation on the day of diagnosis of NEC, treatment with vasopressors at the time of diagnosis, and Black race. Patients who received only ampicillin and gentamicin on the day of diagnosis were less likely to die. Two-thirds of NEC deaths occurred quickly (<7 days from diagnosis), with a median time of death of one day from time of diagnosis. Infants who died within 7 days of diagnosis had a higher birth weight, more often were on vasopressors and high frequency ventilation at the time of diagnosis compared with patients who died at 7 or more days. Although mortality decreased with increasing gestational age, the proportion of deaths that occurred within 7 days was relatively consistent (65 to 75% of the patients who died) across all gestational ages.

Conclusion: Mortality among infants who have NEC remains high and infants who die of NEC commonly (66%) die quickly. Most of the factors associated with mortality are related to immaturity, low birth weight and severity of illness.

Figure 1

(a) The occurrence of NEC by gestational age. (b) Mortality in infants who had a diagnosis of NEC by EGA. The number listed within parentheses represents the number of patients with NEC within each gestational age group. Mortality for infants with NEC decreases with increasing gestational age. The dark bars represent death at 7 or more days from diagnosis of NEC and the light bars represent deaths that occurred less than 7 days from diagnosis. Although mortality decreased with increasing gestational age, the proportion of deaths that occur within 7 days was relatively consistent (65 to 75% of the patients who died) across all gestational ages.