[Methodological aspects of interpretation of thyroid-stimulating hormone reference intervals in the Northwest region...

The prevalence of subclinical hypothyroidism (SH) is large and according to various studies is from 3 to 21%. In the Russian Federation to date, there are no major epidemiological studies assessing the functional state of the thyroid gland. It seems relevant to study the TSH level in patients who turned to the clinical units of a large hospital in the North-West region to determine the prevalence of thyroid dysfunction in patients of different sex and age. 5,303 patients were examined, who applied to the I.P. Pavlov SPbSMU clinics for 2017. In all patients the level of TSH and free T4 was determined. SH was considered to increase the level of TSH more than 4.0 mIU/l at a normal level of free T4. Patients were divided into groups by age and TSH level in accordance with existing recommendations. Among the examined patients were 29.26% of men and 70.73% of women. The mean age was 55.08 ± 17.07 years. The TSH level had an abnormal distribution and averaged 2.77 mIU/l (TSH median 1.73 mIU/l). In women the level of TSH was significantly higher in all studied groups of patients (p = 0.0001). Among women, significant differences in the level of TSH between the elderly and young patients (p = 0.015) were found. The incidence of SH in the total group of patients was 10.1%. In the men surveyed, the incidence of SH was 7.3%, and in the female group - 11.3%. In the elderly patients, the incidence of subclinical hypothyroidism in women was 2 times higher than that of men. In most cases (77.4%) in patients with SH, the TSH level was in the range of 4.0-6.9 mIU / L. The clinical significance of minimal thyroid insufficiency requires further study.