Introduction
Search Strategy
Prevalence of Diabetes and Thyroid Dysfunction
Clinical Guidelines on Screening for Thyroid Disorders in Diabetes
Guidelines | Screening recommendations in diabetes | Comments |
---|---|---|
2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum [11] | In high-risk women, serum TSH to be tested at baseline; reflex anti-TPO if TSH is 2.5–10 mU/L | T1DM considered high risk. No specific comments about T2DM |
2012 Clinical Practice Guidelines for Hypothyroidism in Adults: cosponsored by The American Association of Clinical Endocrinologists and The American Thyroid Association [15] | Thyroid palpation and serum TSH measurement at baseline and at regular intervals in T1DM patients, especially if goitre or autoimmune disease present | No specific comments about T2DM |
2006 UK Guidelines for the Use of Thyroid Function Tests by the British Thyroid Association and the Association of Clinical Biochemistry Guidelines [14] | TFT at baseline and annually for T1DM. In T1DM, TSH, FT4, and anti-TPO measured preconception, at booking, and at 3 months postpartum. TFT at baseline for T2DM | Annual tests not recommended for T2DM |
2015 NICE Guideline for Type 2 Diabetes in Adults: Management [12] | No mention of monitoring thyroid function in T2DM | |
Standards of Medical Care in Diabetes—2017 by the American Diabetes Association [13] | Thyroid palpation at presentation. At T1DM diagnosis, tests recommended for anti-TPO, anti-TG, and TSH. Frequent rechecking if symptoms suggest TD | No mention of monitoring thyroid function in T2DM or GDM |
Italian Association of Clinical Endocrinologists and Italian Association of Clinical Diabetologists Position Statement: Diabetes Mellitus and Thyroid Disorders: Recommendations for Clinical Practice [16] | TFT at baseline and annually for T1DM patients TFT during DKA with careful evaluation Re-evaluation of newly detected hyperglycaemia in hyperthyroid subjects Serum TSH assay in case of repeated hypoglycaemia In diabetic patients with SCH, TSH check every 6 months | Routine ultrasound screening of thyroid gland at T2DM diagnosis is not suggested |
Clinical Implications of Diabetes and Thyroid Disease Coexistence
Thyroid Hormones and Glucose Homeostasis
Organ/cells | Effect on glucose metabolism |
---|---|
Gastrointestinal tract | Increased glucose absorption |
Liver | Increased hepatic gluconeogenesis |
Adipose tissue | Increased lipolysis; increased serum free fatty acid |
Skeletal muscle | Increased glucose uptake |
Pancreatic beta cells | Increased insulin secretion |
Pancreatic alpha cells | Increased glucagon secretion |
Effects of Diabetes on Thyroid Disorders
Diabetes Mellitus, Thyroid Dysfunction, and Pregnancy
Subclinical Hypo- or Hyperthyroidism in Diabetes
Thyroid Nodules and Carcinoma in Diabetes
Glycated Albumin Levels
Seaweed in the Diet
Effect of Drugs on Thyroid Function and Glycaemic Control
Drugs | Effects of anti-diabetic drugs on thyroid function in patients with T2DM |
---|---|
Reduces TSH level Reduces risk of thyroid cancer Reduces thyroid volume and nodule size May be a promising therapy for patients with TD | |
Sulfonylureas [55] | Increases the risk of thyroid cancer Increases risk of hypothyroidism and goitre |
Inhibits the activity of thyroid hormone receptors Increases TSH Increases IGF-1 Decreases FT4 Aggravates thyroid-associated orbitopathy |
Drugs | Effects of anti-thyroid drugs on glycaemic control |
---|---|
Methimazole [24] | Is related to the development of insulin autoimmune syndrome May cause hypoglycaemia in patients with diabetes |
Carbimazole [57] | Insulin autoimmune syndrome has been reported |
Levothyroxine [58] | Reduces fasting and postprandial glucose levels Reduces the glycosylated haemoglobin level |