Call for more thyroid function tests for older patients to improve diagnosis rate

Mar 17 2009

A new study of over 3500 patients with overactive thyroids shows that elderly patients experience fewer signs and symptoms of the condition.

This study, which will be presented at the annual Society for Endocrinology BES meeting in Harrogate, is the largest study to date to show a difference in symptoms in patients with overactive thyroids according to age.  The authors, Dr Kristien Boelaert and colleagues at the University of Birmingham, now call for clinicians to adopt a lower threshold for performing thyroid function tests in older adults.

The thyroid is an endocrine gland that produces hormones which control the body's metabolism.  When the thyroid becomes overactive due to disease, it releases an excess of thyroid hormones into the bloodstream, a condition called hyperthyroidism.  Hyperthyroidism is common, affecting up to 2% of the UK population and is most prevalent in young and middle-aged women.  It causes the body's metabolism to speed up, leading to a variety of symptoms including weight loss and tiredness.  

Hyperthyroidism often goes undiagnosed, especially in elderly patients, despite the presence of clinical symptoms.  To investigate further, Dr Kristien Boelaert and colleagues looked at the influence of age on the clinical symptoms of 3563 UK patients with hyperthyroidism.  They divided these patients into four groups according to their age:  16-32 years (n=877); 33-44 years (n=878); 45-60 years (n=926); 61-91 years (n=882).   

They found classic symptoms of hyperthyroidism such as palpitations, tremor, anxiety, heat intolerance, diarrhoea and neck swelling were less common in older patients.  Patients in the older age group were more likely to present with no symptoms (13%; 12%; 11%; 17% in respective groups, p <0.001) and least likely to experience five or more symptoms (29%; 33%; 32%, 13%, p><0.001).  This could explain why hyperthyroidism often goes undiagnosed in this older age group. The authors are now calling on clinicians to offer thyroid function tests more readily to older adults, to improve the diagnosis rate of hyperthyroidism in this age group.>

Researcher Dr Kristien Boelaert said:

“Hyperthyroidism affects up to 2% of the population but often goes undiagnosed, especially in the elderly.  In this study, we assessed the clinical symptoms of patients with hyperthyroidism in different age groups.  Our findings show that classic symptoms of hyperthyroidism are less common in older patients who have different clinical profiles.  We show that older adults with raised thyroid hormone levels are likely to experience fewer symptoms, making hyperthyroidism more difficult to detect.  This helps to explain why hyperthyroidism often goes undiagnosed in elderly patients.  We now call on clinicians to lower the threshold for performing thyroid function tests in older adults, in order to improve the diagnosis rate of hyperthyroidism in this age group.”