Nutritional Status Trajectory in Children and Adolescents With Repaired Tetralogy of Fallot: A Retrospective Longitudinal Cohort Study From a Latin American Tertiary Center

<title>Abstract</title> <p>Purpose Improved survival in repaired tetralogy of Fallot (rToF) has shifted attention to long-term comorbidities, notably obesity, a modifiable risk factor for adverse remodeling and mortality. We hypothesized that children with rToF show a significant upward body mass index Z-score (zBMI) trajectory during follow-up despite a lower prevalence of excess weight than the general pediatric population. Methods Retrospective longitudinal cohort of 70 patients with rToF aged 5–18 years followed at a Chilean tertiary center between 2015–2024. Excess weight was defined as zBMI ≥ + 1 (WHO 2007). Baseline and final assessments were compared with Wilcoxon signed-rank tests; subgroups (sex, anatomy, type of repair) with Mann-Whitney U or Kruskal-Wallis tests. Subgroup analyses were exploratory and unadjusted for multiplicity. Results Mean follow-up was 3.6 ± 2.4 years. Final prevalence of excess weight was 31.4% (95% CI 21.8–43.0), lower than the Chilean national estimate of 51.4%. Median zBMI rose from − 0.09 (IQR − 0.71 to 0.80) to 0.31 (IQR − 0.27 to 1.23; p = 0.003), and 12.9% (95% CI 6.9–22.7) moved from normal weight or underweight to excess weight. Patients with pulmonary atresia and major aortopulmonary collateral arteries had lower baseline zBMI (p = 0.02) but higher final left ventricular end-diastolic diameter Z-scores (p = 0.03). Only the complex-repair subgroup showed a significant zBMI increase (p = 0.04). No differences were found by sex. Conclusion Children with rToF had a lower prevalence of excess weight than the general population but a significant upward zBMI trajectory, supporting longitudinal nutritional surveillance in routine rToF follow-up.</p>