Risk factors of the development of vascular and neuropathic complications in patients with type 2 diabetes mellitus and autoimmune thyroiditis
Authors: Meleshkevich T. A. , Kurnikova I. A. , Mitichkin A. E. , Luchina E. I. , Shevchenko M. E. , Slonimskaya G. A. , Zernova E. V. , Martynova E. N. , Kiryanova L. V. 
Published: March 2021

Issues of the formation and progression of late complications of diabetes mellitus remain interesting and foreground today, especially in cases of type 2 diabetes mellitus (dm) combined with other endocrine diseases. The pathogenetic relation between the mechanisms leading to blood vessels and nerves damage against the background of diabetes mellitus, and, for example, mechanisms of autoimmune thyroid abnormality (ait), is far from being unambiguous, but the very fact of its existence cannot be denied.

Purpose: to determine the predominant type of comorbidity (trans-syndromal, trans-nosological or chronological) and the level of comorbidity according to the disease rating scale (cirs) in patients with type 2 diabetes and ait, to study the structure of later complications of diabetes mellitus in this group of patients and to assess the contribution of certain factors to increased risk of complications.

Methods. 428 patients were examined in a specialized endocrinology department, and two groups were formed: an observation group — 213 people with diagnosed type 2 diabetes and ait, and a comparison group — 215 people with a diagnosis of type 2 diabetes. These groups were comparable in age, the duration of diabetes, body mass index, correction of the disease. The analysis included clinical and laboratory parameters, the results of hormones level studies (tsh, free t4, insulin, c-peptide) and antibodies (at-tpo), thyroid ultrasonography, calculation of the insulin resistance index (homa) and the comorbidity index (cirs — cumulative illness rating scale) followed by a correlation-regression analysis of statistical data. The state of the peripheral nervous system was evaluated with the use of electromyography in patients of both groups, and the severity of diabetic neuropathy was evaluated with the use of the neuropathy disability score and vas (visual analogue scale) scales. The state of the vascular system was studied according to the data of ultrasound examination of the vessels of the lower extremities, echocardiography, and ophthalmoscopy.

Results. The obtained data made it possible to determine the factors infl uencing the risk of type 2 diabetes complications developement, and to establish that neuropathic complications begin and progress faster in patients with comorbid endocrine pathology, however, there is no such dependence for vascular complications. According to the linear regression equation of the dependence of total complications on the duration of the disease, it was revealed that the development of vascular complications in patients with combined endocrinopathy occurs even more slowly than in patients with diabetes. The contribution of diabetes compensation and identifi ed risk factors to the progression of diabetic complications was less important for patients with endocrinopathies. As for evaluating the contribution of individual parameters, the most signifi cant were the duration of diabetes mellitus, albuminuria, atherosclerosis of the vessels of the lower extremities.

Conclusion. In addition to the known risk factors for the development and progression of vascular complications, in patients with overlapping endocrinopathy, the preservation of residual insulin secretion and renal function (chronic kidney disease, proteinuria) were important. the prevalence of “total” Complications in the group of patients with combined endocrine pathology was lower, however, neuropathic complications in the same group were observed more often,т which indicates the primary eff ect of thyroid dysfunction on the structure of the nervous tissue.