Should we be screening for thyroid dysfunction in patients with type 2 diabetes mellitus?

Abstract

There are increasing data to support a link between type 2 diabetes mellitus (T2DM) and thyroid disease. Screening for thyroid disease in patients with T2DM may therefore warrant consideration, particularly because the biochemical testing involved is straightforward. However, this is not recommended in current guidelines. This article will discuss the link between these conditions and explore the gaps in guidance regarding screening patients with T2DM for thyroid dysfunction. Data from a large European meta-analysis indicate that the prevalence of thyroid dysfunction in the general population, including subclinical disease, is 3.82%, with 3.05% and 0.75% for hypothyroidism and hyperthyroidism, respectively.1 Several cross-sectional studies have illustrated a significantly higher prevalence of thyroid disorders in patients with T2DM.2–6 The largest of these studies found that prevalence of thyroid dysfunction in patients with T2DM was 6.9% in males and 10.9% in females.2 Similar findings have been reported in a number of smaller studies (details available from authors on request). Consistent with findings in the general population,1 in patients with T2DM, thyroid dysfunction was more prevalent in females than males and cases of hypothyroidism more frequent than hyperthyroidism. Biochemically subclinical hypothyroidism was generally the most common finding, though one study demonstrated preponderance for overt disease. A number of studies either excluded participants with previously known thyroid disease,3,4 or performed a sub-analysis on this group.2,5,6 In these circumstances, subclinical hypothyroidism was clearly the predominant finding, suggesting that the majority of undiagnosed thyroid disease would be of this type; this observation was consistent with those made in the general …