Estimation of Serum Iron Status in Patients with Cyanotic Congenital Heart Disease – A Cross-Sectional Study

Background: Cyanotic congenital heart disease (CCHD) is associated with chronic hypoxia, leading to compensatory erythrocytosis and paradoxically elevated hematological indices, which can mask underlying iron deficiency anemia (IDA). Objective: To assess the serum iron levels and prevalence of IDA in patients with CCHD. Methods: This cross-sectional study was conducted from July 1, 2021, to December 31, 2022, at All India Institute of Medical Sciences (AIIMS) Rishikesh for 18 months, enrolling 127 children aged 6 months to 18 years with unrepaired CCHD. Serum iron, ferritin, total blood count, and erythrocyte indices were assessed. Nutritional assessment, anthropometric measures, and socioeconomic data were collected. Different erythrocytic indices were compared between iron-deficient and non-iron-deficient groups. Results: A total of 127 children, with a mean age of 5.6±4.7 years, were included in the study. The most frequent CCHD was Tetralogy of Fallot (55.1%). Based on serum iron and ferritin levels, 25 participants (19.7%; 95% CI: 12.7%–26.7%) had iron deficiency. Comparison of hematological indices showed no significant difference in mean hemoglobin (16.7 g/dL in both groups; p = 0.99) and hematocrit (52.6 vs 53.2; p = 0.86) between iron-deficient and non-iron-deficient groups. Similarly, mean corpuscular volume (77.3 vs 80.5 fL), mean corpuscular hemoglobin (25 vs 24.4 pg), and mean corpuscular hemoglobin concentration (28.4 vs 28.9 g/dL) differences were also not statistically significant. Conclusion: The study revealed that 19.7% of children with CCHD have iron deficiency. Neither the clinical predictors of iron deficiency nor the erythrocytic parameters varied between the two groups, underscoring the importance of routine iron status evaluation.