Endocrine Abstracts

Introduction: Thyroid dysfunction is one of the commonest endocrine disorders with hypothyroidism being the most common thyroid dysfunction in the elderly population^[1]. An elderly patient with thyroid dysfunction can be asymptomatic, or present with non-specific symptoms, making biochemical testing of thyroid function useful and essential. We reviewed the screening rate and prevalence of thyroid dysfunction in older medical patient patients admitted to an Irish secondary hospital.

Methods: A retrospective cross-sectional analysis was conducted on all hospitalized general medical patients over 70 years of age discharged during October 2020. This was identified using the Integrated Patient Management system. Chart review was carried out to identify those with a known diagnosis of thyroid disorders. Thyroid function test (TFTs) screened during admission and/or within the prior six months were include in the analysis. Data was inputted to a Microsoft excel spreadsheet and analysed. The thyroid stimulating hormone (TSH) level is measured using the Roche assay and its reference range is between 0.27 - 4.2 mIU/l.

Results: 202 patients were included in this study with a median age of 80 years (SD 6.3). 51%(n= 102) were male. 85% of the entire cohort (n= 171) had TFTs performed. 21%(n= 42) had a known thyroid disorder. TFTs were performed in 95 % of those (40/42). 33% (13/40) had abnormal TFTs requiring a medication adjustment. Of those with no known thyroid disorder, 82% (131/160) had TFTs performed. 11%(n= 14) had abnormal results. 8%(n= 10) had high TSH levels. One had overt hypothyroidism and the remaining 9 had subclinical hypothyroidism, providing a prevalence of 0.8% and 6.9% respectively. The mean age of the patients with subclinical hypothyroidism was 79.9 years (SD 8.1). 3.1% (4/14) had subclinical hyperthyroidism, providing a prevalence of 3.1% with mean age of 83.5 years (SD 3.7).

Discussion: We observed a high prevalence of abnormal TFTs in those with known thyroid disorders, leading to medication adjustment. Screening those without known thyroid disease also yielded abnormal results in 11%. Subclinical hypothyroidism was the most prevalent thyroid disorder among the elderly population in our study. These findings indicate that routine, opportunistic testing of TFTs in medical patients over 70 is beneficial, with medication adjustment required in 33% of those with known thyroid disorder, and 11% of the remainder having abnormal TFTs.

References: 1. Faggiano A, Del Prete M, Marciello F, Marotta V, Ramundo V, Colao A. Thyroid diseases in elderly. Minerva Endocrinol. 2011 Sep 1;36(3):211-31.