To establish the changes of thyroid gland in patients with rheumatoid arthritis (RA) in the presence of subclinical hypothyroid dysfunction (hypoSTD). Material and methods. 457 patients with RA were examined. 68 people (14.6%) were identified, including 63 women (13.5%), with hypoSTD. All female patients with RA and hypoSTD were assigned to Group I. Group II (comparison group) included 44 women with RA without hypoSTD. Results. The thyroid gland (TG) volume in patients of group I averaged The volume of the thyroid gland (TG) in patients of group I averaged 11.15 cm3 (ml) (LQ - 9.5; UQ - 13.2) and was significantly lower than the values in group II – 14.06 cm3 (LQ - 13.3; UQ - 16.2) (U=780, p<0.05). With an increase in RA activity, the TG volume decreased in both groups. However, in patients of group II, this decrease was of a tendency nature (p >0.05), whereas in group I, the differences between the values in patients with low and high activity acquired statistical significance (U =763; p<0,05). Moreover, the volumetric TG indices in individuals of group I with a high degree of RA activity were significantly lower than in group II. Depending on the duration of RA, a decrease in the volumetric TG indices was noted. However, in patients of group I, the decrease in thyroid volume from 14,6 cm3 with RA duration of up to 6 years to 8,9 cm3 with duration >10,5 years was statistically significant (p <0,05), whereas in patients of group II these changes were of a tendency nature (p >0,05). Moreover, the thyroid volume in patients of group I was smaller than in patients of group II with a significant difference in patients with RA duration from 6.5 to 10 years (p <0,05). A study of the relationship between individual parameters of RA patients and hypothyroidism showed that the development of hypothyroidism in RA patients is influenced by the duration of arthritis (kKW =8,86, p =0,003), the presence and age of menopause (kKW =4,23, p =0,039; kKW =6,36; p =0,012, respectively), thyroid volume (kKW=8.0, p=0.0046), as well as seropositivity (the presence of rheumatoid factor) (kKW =13,1, p<0,001). Conclusion. The study showed an inverse relationship between the volume of the TG and the activity and duration of RA, which, given the high connection with seropositivity, may indicate autoimmune nature of systemic inflammation, manifested by both RA and hypothyroidism, or the comorbidity of these diseases, which requires mandatory and dynamic monitoring of the thyroid gland in patients with RA.

Boris Rebrov is an Federal State Budgetary Educational Institutional of Higher Education «Saint Luka Lugansk State Medical University» of the Ministry of Health of the Russian Federation