Screening for thyroid disease in patients with type 2 diabetes mellitus: An evaluation of current practice

Abstract

Background: United Kingdom national guidelines do not recommend routine testing for thyroid disease in people with type 2 diabetes mellitus (T2DM). However, some studies suggest an increased risk of thyroid dysfunction in T2DM. The aim of this study was to evaluate the current practice of screening for thyroid disease in patients with T2DM. Methods: Patients with pre-existing T2DM (n = 339) were selected from records for routine glycated haemoglobin testing performed in December 2008. Using routinely collected primary/secondary care data from 2009 to 2017, we examined longitudinal thyroid-stimulating hormone and free thyroxine requests to determine the overall proportion of patients screened for thyroid dysfunction and the time interval between thyroid tests requested. Results: Thirty-three patients (9.7%) had pre-existing thyroid disease. Of the remaining 306 patients, 96.4% had at least one thyroid test during the follow-up period. When the time interval between tests was evaluated in these patients, there was a discrete peak in thyroid function test requests at 12 months, consistent with routine annual testing. Most requests (77%) originated from a general practice setting. Conclusions: Contrary to current guidelines, we have provided evidence suggestive of regular screening for thyroid dysfunction in patients with T2DM, particularly in general practice. The appropriateness of this practice remains unclear, but may warrant further examination to assess the clinical benefits of screening, balanced against cost.