Screening of Undiagnosed Hypothyroidism in Elderly Persons with Diabetes according to Age-Specific Reference Intervals for Serum Thyroid Stimulating Hormone and the Impact of Antidiabetes Drugs

Abstract

Background. Studies have suggested that hypothyroidism is more frequent in the elderly with diabetes mellitus. However, an adaptation of TSH levels to age should be considered in this assessment. Some antidiabetes drugs reportedly interfere with TSH levels. The objectives of this study were to evaluate the prevalence of undiagnosed hypothyroidism in patients with diabetes and the influence of antidiabetes drugs. Material and Methods. 1160 subjects, 60 years and older (751 with diabetes), were studied; results were compared according to diabetes treatment and with persons without diabetes. TSH, FT4, antithyroperoxidase, fasting glucose, and HbA1c were measured. Results and Discussion. 6.4% of patients with diabetes had hypothyroidism, a higher prevalence compared with persons without diabetes (5.1%), but lower than observed in many studies. The use of age-specific TSH reference interval (RI) could explain this difference. Patients taking metformin (MTF) had TSH (showed in medians) slightly lower (2.8 mU/L) than those not on MTF (3.3 mU/L), p < 0.05. MTF doses influenced TSH levels. Conclusions. The use of specific TSH RI could avoid the misdiagnosis of hypothyroidism in elderly with diabetes. Patients in use of MTF as single drug had lower TSH than those using other medications and persons without diabetes.

Thyroid Hormone Reference Intervals among Healthy Individuals In Lanzhou, China

“…Because TSH levels gradually increase with age, some elderly people might be diagnosed with subclinical hypothyroidism. The prevalence of subclinical hypothyroidism may be significantly overestimated unless age-specific TSH RIs are used [ 46 , 47 ]. However, inconsistent evidence has been reported on the effects of age on TSH levels [ 4 , 11 ].…”

Effects of Metformin on TSH Levels and Benign Nodular Goiter Volume in Patients Without Insulin Resistance or Iodine Insufficiency

“…A preliminary study demonstrated that MTF administration in subjects with IR was associated with significant reduction in TSH levels and increase in levels of free tri-iodothyronine (FT3) with no change in free tetra-iodothyronine (FT4) (7). In a study with elderly people with type 2 diabetes, the patients with diabetes who were given MTF had lower TSH levels compared to non-diabetic patients in addition to patients treated with other antidiabetic agents (13).…”

Lower limb oedema in diabetes

“…Hypothyroidism may cause myxoedema or mucus swelling (Greek Myxa ) from mucopolysaccharides. In a Brazilian study, 6.4% of people with type 2 diabetes had hypothyroidism . A Spanish study found that the relative risk of new hypothyroidism in patients with type 2 diabetes was 2.81 (1.77–4.48) vs controls .…”