**Background:** Hirschsprung disease (HSCR) is a congenital disorder of colonic aganglionosis with an incidence of ~1/5000 live births in China. While surgical mortality is low, optimizing overall management—including nutrition assessment—is critical for reducing postoperative complications. Undernutrition is known to predict poor outcomes in pediatric surgical patients, but its prevalence in HSCR was previously unknown. This study aimed to describe preoperative nutrition status in children with HSCR and explore associations with postoperative Hirschsprung-associated enterocolitis (HAEC).
**Methods:** This retrospective multicenter cross-sectional study included children with histologically confirmed HSCR who underwent primary transanal endorectal pull-through (ERPT) at <5 years of age between January 2016 and December 2020 at three Chinese tertiary centers: Tongji Hospital, The First Affiliated Hospital of Zhengzhou University, and Hunan Children's Hospital. Of 718 eligible patients, 624 were analyzed after excluding those with total bowel aganglionosis, additional nutrition deficiencies, prior colostomy, reoperation, or incomplete records. Weight and height measured on admission were used to calculate WAZ, HAZ, and BAZ via WHO Anthro software. Undernutrition was classified as low (−1 to −1.9 z-score), moderate (−2 to −2.9), or severe (≤−3). Postoperative HAEC was diagnosed based on fever, vomiting, foul-smelling watery diarrhea, or abdominal distention. Statistical analyses included t-tests, ANOVA, chi-square tests, and univariate/multivariate logistic regression using SPSS 26.
**Key Results:** The cohort was 82.1% male (n=512), with a median age of 9 months (range 0–60 months). Age distribution: 63.1% (n=394) aged 0–12 months, 25.8% (n=161) aged 13–36 months, and 11.1% (n=69) aged 37–60 months. Aganglionic segment distribution: short-segment 32.5% (n=203), classic-segment 51.1% (n=319), long-segment 12.3% (n=77), total-colon 4.0% (n=25). Mean WAZ, HAZ, and BAZ were −0.64±1.40, −0.45±1.77, and −0.43±1.50, respectively. Moderate to severe overall undernutrition (WAZ ≤−2) was 16.3% (102/624). WAZ ≤−1, ≤−2, and ≤−3 were observed in 18.1%, 10.6%, and 5.8% of patients, respectively. HAZ ≤−2 was 15.3%, and BAZ ≤−2 was 17.1%. WAZ and BAZ were significantly lower with longer aganglionic segments (P=0.001 for both). Moderate to severe undernutrition by segment: short-segment 13.8%, classic-segment 13.8%, long-segment 23.4%, total-colon 48.0% (P=0.001). Older age at surgery was associated with lower HAZ (P=0.01). Postoperative HAEC occurred in 38 of 512 patients with available follow-up data (loss to follow-up 17.9%). Multivariate logistic regression identified lower WAZ (P=0.001), female sex (P=0.03), and older age at surgery (P=0.001) as independent risk factors for postoperative HAEC.
**Clinical Implications:** This study provides the first large-scale evidence that undernutrition is prevalent (16.3% moderate to severe) among children with HSCR at the time of admission for surgery. Longer aganglionic segments and delayed diagnosis/treatment are associated with worse nutrition status. Importantly, lower WAZ independently predicts postoperative HAEC, a serious complication. The authors recommend routine preoperative anthropometric screening using simple weight and height measurements to identify at-risk children for early nutrition intervention. A prospective trial (NCT04598841) is underway to evaluate whether preoperative nutrition support improves outcomes.