J.M. Rook1, N. Chervu1,2, J. Vankawala1, K. Calkins3, P. Benharash1,2, D. DeUgarte1 1David Geffen School Of Medicine, University Of California At Los Angeles, Department Of Surgery, Los Angeles, CA, USA 2David Geffen School Of Medicine, University Of California At Los Angeles, Cardiovascular Outcomes Research Laboratories (CORELAB), Los Angeles, CA, USA 3David Geffen School Of Medicine, University Of California At Los Angeles, Division Of Neonatology & Developmental Biology, Department Of Pediatrics, Los Angeles, CA, USA
Introduction:
Textbooks attribute 80% of meconium-related small bowel obstructions to cystic fibrosis and 15% of colonic obstructions to Hirschsprung’s disease. It is unknown if these estimates are accurate among preterm neonates, whose functionally immature bowel predisposes them to meconium obstruction. This study seeks to establish the incidence of meconium-related obstruction among preterm infants, determine rates of comorbid cystic fibrosis and Hirschsprung’s disease, and define its impact on clinical outcomes.
Methods:
We included liveborn preterm neonates within the National Inpatient Sample from 2016-2020. We used survey weighting methodology to estimate the national incidence of meconium-related obstruction by etiology. Multivariable regressions were developed to evaluate (1) patient characteristics associated with the likelihood of developing a meconium-related obstruction and (2) the association between meconium obstruction of prematurity and mortality, need for surgery, length of stay, and hospitalization costs after adjusting for sociodemographic and clinical characteristics.
Results:
Of 322,499 preterm infants, 634 (0.2%) were diagnosed with a meconium-related obstruction. Among these, 604 (95.2%) occurred in the absence of cystic fibrosis or Hirschsprung’s disease yielding disease incidences of 187:100,000 for meconium obstruction of prematurity and 4.7:100,000 for meconium ileus of cystic fibrosis and meconium plug syndrome of Hirschsprung’s disease.
On adjusted analyses, neonates with gestational ages between 28 weeks and 31 weeks 6 days (OR 1.74; CI 1.24-2.43; p<0.001) and those with birth weights <1000 gm (OR 4.87; CI 3.09-7.69; p<0.001) were at highest risk for meconium obstruction when compared to infants born late preterm (≥34 weeks) and normal birth weight (≥2,500 gm), respectively (Figure 1). Small for gestational age (OR 1.36; CI 1.03-1.81; p=0.03) was associated with obstruction.
Meconium obstruction of prematurity was associated with a 4.2 percentage point increase in the probability of abdominal surgery (CI 3.1-5.4; p<0.001), a 7.3-day increase in length of stay (CI 5.8-8.8; p<0.001), and a $23,215 increase in hospitalization costs (CI 17,739-28,690; p<0.001) when compared to unobstructed infants.
Conclusion:
Cystic fibrosis and Hirschsprung’s disease are rare causes of meconium-related obstruction in preterm neonates. Workup for these predisposing conditions may not be necessary for all preterm infants treated for a meconium-related obstruction. Infants who developed meconium obstructions more frequently required surgery and had longer and more costly hospitalizations. Dedicated prevention and treatment pathways are needed for this understudied disease.