A Prospective Observational Study Evaluating Thyroid Hormone Profile Alterations in Patients with Acute Coronary Syndrome and Their Association with Clinical Outcomes

Abstract

Background: Thyroid hormones play a crucial role in cardiovascular physiology, influencing myocardial contractility, vascular resistance, andmetabolic regulation. Alterations in thyroid hormone levels, particularly low triiodothyronine (T3), are frequently observed in patients withAcute Coronary Syndrome (ACS) and may impact disease severity and prognosis. Aim: To evaluate thyroid hormone profile alterations in patients with ACS and determine their association with clinical outcomes in a tertiarycare center in Bihar. Methodology: This prospective observational study included 100 adult patients diagnosed with ACS during the study period. Patients wererandomly selected from those presenting to the outpatient and emergency departments. Thyroid function tests (Free T3, Free T4, and TSH) weremeasured within 24 hours of admission using chemiluminescent immunoassay. Patients were categorized into euthyroid and thyroid dysfunctiongroups. Clinical outcomes, including mortality, heart failure, arrhythmias, cardiogenic shock, and duration of hospital stay, were recorded andanalyzed using appropriate statistical tests. Results: Thyroid dysfunction was observed in 40% of patients, with low T3 syndrome being the most common abnormality (22%). Patientswith thyroid dysfunction had significantly higher mortality (25 vs 5%), increased incidence of heart failure (40% vs 13.3%), arrhythmias (35 vs10%), and longer hospital stay (8.6 ± 2.1 vs 5.2 ± 1.3 days) compared to euthyroid patients (p <0.05). Conclusion: Thyroid hormone abnormalities are common in ACS and are significantly associated with adverse clinical outcomes. Thyroidfunction testing may serve as a simple and cost-effective prognostic tool for risk stratification in ACS patients.