²Asmaa Hegazy, ¹Shatha Khalid Bin Dher, ³Fahad Aleidan, ⁴Raghad Alhindi,⁵Mohammed M. AlAmri, ²Saitah Alshammari

¹Collage of Medicine, King Saud University, ²Rheumatology, Internal Medicine, King Saud Medical City, ³Medicine, Prince Sultan Military Medical City, ⁴Internal Medicine, National Guard Hospital, ⁵Head of Internal Medicine Department, King Saud Medical City

Background(s): Autoimmune Thyroid Diseases (AITD) coexist with conditions like Sjögren’s syndrome, Rheumatoid arthritis (RA), and Diabetes mellitus.(1) Studies show a significant association between RA and thyroid dysfunction, emphasizing its independent and notable correlation. (2-3) Investigations reveal heightened thyroid dysfunction prevalence in SLE and RA patients, particularly in females.(4-6) Studies in Egypt and Jeddah confirm elevated thyroid dysfunction prevalence in RA patients.(8-9) It is crucial for autoimmune patients to manage thyroid issues with healthcare. The study aims to determine thyroid dysfunction prevalence and characteristics in RA patients at King Saud Medical City, focusing on early screening and comprehensive investigations.

Method(s): A retrospective cohort study conducted at King Saud Medical City (KSMC), Riyadh, Saudi Arabia. From August to November 2023, focused on 158 Rheumatoid Arthritis (RA) patients meeting American Rheumatism Association criteria spanning 2016 to 2021. Data were collected, without formal sample size calculation due to the retrospective design, including all eligible patients. All patients underwent clinical examination and tests for thyroid function and RA-specific auto-antibodies, with the primary outcome focused on the presence or absence of thyroid disorders.

Result(s): 158 RA patients were included; main treatments were: biological treatment (23.4%), with Rituximab, Humira, and Enbrel (1 case each); 4 cases (2.5%) received no treatment. In RA patients: 85 (53.8%) seropositive, including 65 (41.1%) RF and 58 (36.7%) ACPA seropositive. Elevated ESR in 108 (72%); significant DAS 28 in 30 (19%). Anemia in 19 (12%), and deficient vitamin D in 100 (66.7%). Regarding US findings: 29 (28.7%) grade 1 effusion, 30 (29.7%) grade 2, 5 (5%) grade 3 synovitis. 37 (36.6%) had normal findings. Additionally, the prevalence of thyroid disorder in RA patients: 79.9% euthyroid, 16% hypothyroid, 4.2% hyperthyroid. Moreover, we found that vitamin D deficiency is linked to thyroid disorders in RA patients (82.1% vs. 75.6%). Deficiency associated with hyperthyroidism (2.1% vs. 8.9%, P=.048). Also, we found that vitamin D deficiency is not significantly linked to seropositive RA (50% vs. 60%, P=.247). Significantly associated with higher DAS 28 (15% vs. 30%, P=.030).

Conclusion(s): Our study contributes essential insights into the patterns of thyroid functional states among individuals diagnosed with Rheumatoid Arthritis (RA) in the Saudi Arabian population. This information is crucial for gaining a comprehensive understanding of the prevalence of thyroid disorders within this specific demographic. Moreover, the research establishes a significant correlation between Vitamin D levels and disease activity in RA patients. Additionally, our results underscore the importance of vitamin D levels in the context of thyroid disorders among RA patients in Saudi Arabia, emphasizing a substantial association between these variables.