Non-thyroidal Illness in Children with Congestive Heart Failure.

Objectives:To estimate the proportion and risk factors of non-thyroidal illness (NTI) in children with congenital heart disease (CHD) with congestive heart failure(CHF). Methods:This study enrolled children (6 weeks to 60 months age) with CHD and CHF. The clinical profile and disease severity using Pediatric Early Warning Score (PEWS) was recorded. Baseline blood samples were taken within 24hours of hospitalization and evaluated for fT3, fT4, TSH, NT pro-Brain natriuretic peptide (NT pro-BNP) and reverseT3. Results:A total of 80 (64 acyanotic CHD) children of median (IQR) age 5 (2.5, 8.0) months were enrolled. NTI was seen in 37 (46%)- 27 with low fT3 levels. The proportion of NTI was maximum in children with severe disease (20/30), than moderate (4/9) or mild disease (13/41); p=0.018. Ten (27%) patients with NTI expired as compared to 2 (4.7%) without NTI with unadjusted odds ratio (95% CI) 7.593(1.54, 37.38); p-value=0.006. After adjusting for NTI, shock and NT-pro-BNP levels, PEWS was the only significant predictor of mortality (OR 1.41, 95% CI 1.03, 1.92; p=0.032).Linear regression for fT3 showed significant relation with log NT-BNP [beta -3.541, (95% CI -1.387, -0.388)] and with TSH [beta 2.652 (95%CI 0.054, 0.383)]. The cutoff (AUC, 95%CI) that predicted mortality were fT4 <14.5 pmol/L (0.737, 0.60, 0.88), fT3/rT3 index <1.86 pg/ng (0.284, 0.129, 0.438) and NT pro-BNP >3725 pg/mL (0.702; 0.53, 0.88). Conclusion:NTI was seen in a significant proportion of children with CHD and CHF. Free T3 level was significantly affected with NT-BNP levels (severity of CHF).