Endocrine Abstracts

Introduction: The possible clinical impact of subclinical thyroid dysfunction on patients with cardiovascular events is important if one considers the high incidence of a mildly altered thyroid hormone pattern in this population. This study aims to determine the prevalence of subclinical thyroid dysfunction among patients presenting with cardiovascular events in Philippine General Hospital, and its impact on mortality.

Methodology: A cross sectional, prospective cohort study, involving 163 adult patients with cardiovascular events. Pregnant, and all patients who have clinically apparent thyroid disease or taking thyroid medications, or any other medications that may affect thyroid function testing were excluded. Patients were grouped as having overt thyrotoxicosis, subclinical hyperthyroidism, euthyroidism, overt hypothyroidism, subclinical hypothyroidism, or nonthyroidal illness. Demographic and clinical characteristics were expressed as means. Cardiac and overall deaths were considered. Calculations were done using the SPSS program, version 20.0.

Results: Patients with subclinical hyperthyroidism were older (66.9 vs 56.9 years, P value=0.0020), and more were diabetic (55.6 vs 23.6, P value=0.039), while those with subclinical hypothyroidism and nonthyroidal illness have a higher need for mechanical ventilation (33.3 vs 9%, P value=0.026; 25.7 vs 9%, P value=0.015 respectively), compared to euthyroid. Prevalence of subclinical thyroid dysfunction was 32.5%. Of these, 5.5% had subclinical hypothyroidism, 5.5% had subclinical hyperthyroidism, and 21.5% had nonthyroidal illness. Higher incidence of acute coronary event and heart failure among patients with subclinical thyroid dysfunction (P value=0.031) was noted. The overall death rate was also higher (17.3 vs 9.2%).

Conclusion: In patients with cardiovascular events, the prevalence of subclinical thyroid dysfunction was 32.5%. Higher incidence of acute coronary event and heart failure was observed in the population. Subclinical hyperthyroidism was significantly associated with older age and diabetes, while subclinical hypothyroidism and nonthyroidal illness with need for mechanical ventilation.