The Association Between Hypothyroidism And Rheumatoid Arthritis

Background:Hypothyroidism(abbreviated as hypothyroidism)is a clinical disease characterized by a decrease in the metabolic rate of the body caused by decreased synthesis or secretion of thyroid hormones or insufficient physiological effects due to various reasons.Rheumatoid arthritis(RA)is an autoimmune disease with unknown etiology and pathological manifestations of synovitis.It mainly causes irreversible joint injury and severe disability,and can also lead to multiple organ involvement outside the joint.Research has found that hypothyroidism is a common thyroid dysfunction in patients with RA,and the occurrence of hypothyroidism is related to the severity of RA;In addition,hypothyroidism has a certain impact on RA disease activity,drug efficacy and drug safety.The study on the correlation between hypothyroidism and RA is less and not deep enough.There are still many uncertainties about the special relationship between RA and hypothyroidism.Purposes:1.To further confirm the prevalence of hypothyroidism in RA patients,clarify the clinical characteristics of RA with hypothyroidism and the correlation between hypothyroidism and multiple organ damage outside the joint of RA.2.To analyze the correlation between RA,hypothyroidism,thyroid autoantibodies,and multiple organ damage outside the joint of RA,to analyze the risk factors of hypothyroidism in RA patients,to explore the relationship between the two and provide ideas for the study of the mechanism of hypothyroidism in RA patients.Methods:1.719 inpatients with RA were included as the case group and 719 healthy people with sex and age matching were included as the control group.2.The clinical data and laboratory indicators of patients were collected,and the differences between the two groups of continuous variables were compared by t-test,and the differences between the two groups of categorical variables were compared by chi-square test.Multiple logistic regression analysis was used for single or multiple factor analysis.When P<0.05,the difference is statistically significant.All data in this study were statistically analyzed using SPSS Version 25.Results:1.The prevalence of clinical hypothyroidism(5.70%vs.0.42%,P<0.001),autoimmune hypothyroidism(9.32%vs.1.53%,P=0.006),and the positive rate of anti-thyroglobulin antibodies/anti-thyroid peroxidase antibodies(55.35%vs.17.53%,P<0.001)in RA patients were higher than those in the control group,but there was no significant difference in the prevalence of subclinical hypothyroidism.The prevalence of hypothyroidism in RA patients is the highest(20.0%)in the age range of 26 to 36 years,and shows a gradual downward trend with age.The positive rate of anti-thyroglobulin antibodies/anti-thyroid peroxidase antibodies in RA patients showed a trend of first increasing and then decreasing with age,and reached the highest level between 26 and 36 years of age(40.0%).The prevalence of hypothyroidism and the positive rate of anti-thyroglobulin antibodies/anti-thyroid peroxidase antibodies in female patients were higher than those in male patients,both in the case group and the control group.2.Compared with the RA-thyroid normal group,the RA-thyroid hypothyroidism group has higher levels of ESR,C-reactive protein,creatinine,24-hour urine protein,low-density lipoprotein,triglyceride,there are more patients with serositis,anemia,cardiac insufficiency,pulmonary interstitial disease,and renal insufficiency,and lower use rate of glucocorticoids/immunosuppressants.3.In multivariate logistic regression analysis,glucocorticoid/immunosuppressive therapy(AOR,0.216,P<0.001)is an independent protective factor for hypothyroidism patients;Pulmonary interstitial disease(AOR,2.400,P=0.008),cardiac insufficiency(AOR,8.210,P=0.008)and renal insufficiency(AOR,3.580,P<0.001)are independent risk factors for hypothyroidism.Conclusion:Compared with the general population,the prevalence of hypothyroidism in RA patients is higher,and gradually decreases with age.The results suggest that RA patients with pulmonary interstitial disease,cardiac insufficiency and renal insufficiency are at high risk of hypothyroidism.The treatment of RA patients with glucocorticoid/immunosuppressive agent is the independently protective factor of hypothyroidism.We can speculate that the thyroid may also be the affected organ of RA,and RA is one of the causes of hypothyroidism.