Addressing the burden and associated factors of undernutrition in under-five children with congenital heart disease in Pakistan: evidence from a multicenter cross-sectional study

Background Children with congenital heart disease (CHD) are at heightened risk of undernutrition due to elevated metabolic demands, feeding intolerance, and growth failure. This study aimed to identify the associated factors of undernutrition among children under 5 years with CHD in Pakistan. Methods A hospital-based study was carried out among 197 confirmed CHD across three tertiary hospitals in Bannu, Khyber Pakhtunkhwa (KP). WHO-recommended standards and structured questionnaires were used. Multivariable logistic regression analysis was performed to identify independent predictors of undernutrition. Results Overall, 58.9% were male, 40.1% were stunted, 44.2% were underweight, and 35.5% were wasted. Ventricular septal defect was the most common CHD (34.5%), followed by patent ductus arteriosus (23.4%). Infants aged 6–11 months had the most severe deficits. Male children had significantly higher odds of wasting than female children (adjusted odds ratio [aOR] = 2.10, 95% CI: 1.10–3.98), whereas children from households with a monthly income of ≥ PKR 40,000 had lower odds of wasting (aOR = 0.45, 95% CI: 0.24–0.84) and underweight (aOR = 0.52, 95% CI: 0.29–0.94). Similarly, children whose fathers were government employees (aOR = 0.30, 95% CI: 0.09–0.98) also had lower odds of being underweight. No sociodemographic or clinical variables were significantly associated with stunting (all p > 0.05). Conclusion Undernutrition exhibits a high distribution and severity among young CHD children. Multiple associated factors of undernutrition based on wasting and underweight were identified. Timely referrals for nutritional support are of great significance in preventing nutritional deterioration.