Thyroid Dysfunction And Mortality In Cardiovascular Hospitalized Patients – A 12 years Follow-up Observational Study

Background: Thyroid dysfunction (TD) is known to be associated with increased cardiovascular (CV) morbidity and mortality. This, reinforces the importance of early detection and effective treatment. However, information is scarce and specific guidelines are lacking regarding thyroid function screening strategies in patients admitted for acute cardiac conditions.

Aims: To investigate the prevalence, spectrum and significance of thyroid disorders in patients with CV Risk and Disease by thyroid function tests (TFTs) among cardiac patients.

Methods: A retrospective analysis of a medical record database of all consecutive patients (aged 18 years or older) admitted non electively to our heart center from January 1, 2005 through May 1, 2017 for a variety of cardiac conditions in whom thyroid hormone levels is measured routinely as our protocol upon admission.

Results: During the described period there were 19,281 non-elective hospitalizations of 14,388 patients. TFTs were available for 14,384 patients during their 1st hospitalization, age 18-104 years (mean 67±15). TD was found in 10% of the patients (2% TSH>10mIU/L; 5% TSH 5-10mIU/L; 2% TSH 0.1-0.35mIU/L; 1% TSH <0.1mIU/L). The prevalence of TD was significantly higher in older patients (age>70y, 12.1%, Odds ratio[OR]=1.4), patients with atrial flutter/fibrillation (14%, OR=1.4), pulmonary hypertension (14%, OR=1.4), chronic renal failure (14%, OR=1.5), heart failure (15%, OR=1.5), patients with known hypothyroidism treated with Levothyroxin and patients treated with Amiodarone (28%, OR=3.3, 24%, OR=3 respectively). There was no significant prevalence of TD in patients with myocardial infarction or prior cardiac catheterization. Adjusted multi-variable analysis showed increased mortality for TSH<0.35mIU/L, TSH 5-10mIU/L and TSH>10mIU/L (OR=1.6, 1.3 and 1.5 respectively, p<0.001).

Conclusion: The prevalence of thyroid dysfunction in cardiac hospitalized patients is 10% and it is higher in specific hospitalized patients. Patients with thyroid dysfunction have increased mortality rate. Screening for thyroid function should be considered in cardiology departments, especially in selected high risk groups.