Value of High-Sensitivity C-Reactive Protein, Chronotropic Index, and Heart Rate Recovery in Predicting Cardiac Iron Overload in Patients with Beta-Thalassemia Major

Background: Iron-induced cardiomyopathy is the main cause of heart failure in patients with beta-thalassemia major (β-TM). Early diagnosis and timely cardiac iron overload (IO) therapy can improve patients’ prognosis.

Objectives: This study evaluated the value of exercise test parameters and high-sensitivity C-reactive protein (hs-CRP) in detecting cardiac IO in patients with β-TM.

Methods: Forty β-TM patients (age range:18 – 48) were enrolled in this cross-sectional study. Serum hs-CRP was measured using ELISA. Echocardiography and exercise treadmill tests were performed. Cardiac IO was determined using cardiac T2* (CT2*) magnetic resonance imaging, and patients were divided into abnormal (CT2* < 20 ms; n = 22) and normal (CT2* > 20 ms; n = 18) groups. Statistical analyses were conducted using SPSS software. The Mann-Whitney U-test was used to assess differences between the groups. The correlations of variables were evaluated using Pearson’s or Spearman’s correlation analysis. Receiver operator characteristic (ROC) curves were drawn to calculate the optimum cutoff for each test.

Results: We found a significantly higher level of hs-CRP (P = 0.011) and lower levels of the chronotropic index (CI) (P = 0.009) and heart rate recovery (HRR) at minutes 2 – 5 (P < 0.01) in the patients with abnormal CT2*. CT2* was inversely correlated with hs-CRP (r = -0.381, P = 0.022) and positively correlated with the CI (r = 0.346, P = 0.031) and HRR at minute 4 (HRR4) (r = 0.456, P = 0.005). ROC curve data showed diagnostic values of CI (AUC = 0.80, P = 0.005), HRR4 (AUC = 0.786, P = 0.008), and hs-CRP (0.711, P = 0.033) in predicting the severity of IO. These tests showed high sensitivity (CI = 84.6%, HRR4 = 84.6%, and hs-CRP = 85.7%) but low specificity (CI = 70.6%, HRR4 = 41.2%, and hs-CRP = 53.3%) in detecting the severity of cardiac IO.

Conclusion: We found that hs-CRP, CI, and HRRs were significantly associated with the severity of cardiac IO. Despite high sensitivity, these markers showed poor specificity in predicting cardiac iron deposition in β-TM patients.