Impact of subclinical thyroid dysfunction on mortality among patients presenting with cardiovascular events

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 414-431-HPT Axis Biology
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-424
Paulette David Nacpil*1, Maria Luisa Cecilia R. Arkoncel2, Gregory Joseph Ryan Alvior Ardeņa3 and Cecilia A. Jimeno4
1University of Philippines-Philippine General Hospital, Manila, Philippines, 2Philippine General Hospital, Pampanga, Philippines, 3Univeristy of the Philippines-Philippine General Hospital, Manila, 4University of the Philippines, Manila, Philippines
Background: The effects of overt hyperthyroidism or hypothyroidism on the cardiovascular system are well known, but whether subclinical thyroid dysfunctions are of clinical significance remains to be proven. The possible clinical impact of the disease on cardiac patients is important if one considers its high prevalence, and that screening in this population might be a potential strategy to reduce morbidity and mortality.

Objective:  This study aims to determine the prevalence of subclinical thyroid dysfunction among patients presenting with cardiovascular events, at the Philippine General Hospital, and its impact on mortality.

Study Design: Cross sectional, Prospective Cohort Study

Methodology:  163 adults who presented with cardiovascular events were screened for thyroid dysfunction.  Those with subclinical hyperthyroidism [SCT, (n=9)], subclinical hypothyroidism [SCHO, (n=9)], and nonthyroidal illness syndrome [NTIS, (n=35)] were analyzed vs. euthyroid [EU, (n=89).  Demographic and clinical characteristics were expressed as means and frequencies.  Adverse clinical outcomes such as need for mechanical ventilation and inotropic support, and mortality, were considered.  Crude association between subclinical thyroid dysfunction and mortality was evaluated using relative risk and chi-square test.  Calculations were done using SPSS program, version 20.0.

Results: Patients with SCT were older (66.9 vs. 56.9 yr, p value=0.0020), and more were diabetic (55.6 vs. 23.6%, p value=0.039), while those with SCHO and NTIS had 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 EU.  EU had a more significant family history of early cardiac death (7.9 vs. 0%, p value=0.046) and personal history of smoking (52.8 vs. 35.8%, p value=0.05).  Acute coronary event, dysrhythmia and heart failure were statistically different between EU and subclinical thyroid dysfunction groups (p value=0.002, 0.000, 0.030, respectively).  Prevalence of subclinical thyroid dysfunction was 32.5%.  Of these, 5.5% had SCT, 5.5% had SCHO, and 21.5% had NTIS. Overall death rate was higher in subclinical thyroid dysfunction (RR= 1.882). 

Conclusion: There is a high prevalence of subclinical thyroid dysfunction among patients with cardiovascular events, at 32.5%. Subclinical hyperthyroidism was significantly associated with older age and diabetes, while subclinical hypothyroidism and nonthyroidal illness with need for mechanical ventilation.

Nothing to Disclose: PDN, MLCRA, GJRAA, CAJ

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