High TSH and low T4 as prognostic markers in older patients

Abstract

OBJECTIVE: To examine the association between thyroid profile and morbidity/mortality (MM) in hospitalized older patients. DESIGN: This is a retrospective study of patients over the age of 60yr admitted to the Dr. Cesar Milstein Hospital between 2009 and 2010 and who had thyroid function tests (TFT). The patients were grouped as per their thyroid tests and their clinical characteristics and MM was associated with their TFT. High MM was defined as mortality, intensive care unit (ICU) requirement or prolonged hospital stay (>18 days, 75thpercentile), and mortality assessed during an 18-month follow-up period after their hospital discharge. RESULTS: Out of 2599 older patients admitted to our hospital, 7% had TFT performed for various reasons. The patients who had TFT were mostly women and presented in a more serious clinical condition compared to the rest of the patients. The patients were grouped as per their thyroid values as follows: 61% of them had a non-thyroidal illness, 25% were euthyroid, 7% had overt hyperthyroidism, 5% overt hypothyroidism and 1% had subclinical hyper- or hypothyroidism. The hypothyroid patients had a worse clinical outcome compared to the others. Patients with increased MM exhibited higher TSH and lower TT4 (p<0.005). Short-term MM (OR=2.0,95%CI=1.1-3.6, p<0.01) was associated with the decrease of TT4 adjusted by age, sex, T3 and TSH, while for long-term MM the increase in TSH (OR=1.6,95%CI 1.1-2.3, p<0.05) was also significant. CONCLUSION: Among hospitalized older patients who had TFT tests, low TT4 and high TSH were associated with a worse prognosis. We propose that TFT be used as an additional tool in assessing MM in elderly hospitalized patients.