Background Rheumatoid Arthritis (RA) should be treated instantly to prevent further joint destruction. The first few months after treatment initiation are critical for long-term treatment outcome.Patients with RA are at increased risk of thyroid disease with direct effect on initial treatment response.
Objectives To define the prevalence of thyroid disease among RA patients as well as to evaluate the correlation between presence of thyroid disease in RA patients and initial treatment response.
Methods All RA patients who were registered in the local part of Danish Danbio registry were included in this study. Patients' demographic data, serology results including rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (anti-ccp) as well as disease activity score in 28 joints-C-reactive protein (DAS28-CRP) at the time of diagnosis and after 4 months (±1–2 months) of treatment initiation were extracted. ΔDAS28 was calculated as follows: DAS28 at the time of diagnosis – DAS28 after 4 months (±1–2 months) of treatment initiation. Patients' electronic hospital records including laboratory results were reviewed to reveal if they had been diagnosed with thyroid disease.
Results 1035 patients were included in the study (Table 1). Prevalence of thyroid disease was 11.8% (122/1035). Multiple linear regression analysis showed a negative correlation between ΔDAS28 and presence of thyroid disease adjusted for age, gender, disease duration, RF, anti-ccp and DAS28 at the time of diagnosis (Regression coefficient (95% Confidence Interval): -0,157 (-0.312 to -0.002), P=0.047) (Table 2). RA patients with thyroid disease had significantly poorer initial response to RA treatment compared to patients with isolated RA after 4 months of treatment (P=0.002).
Conclusions Presence of thyroid disease in RA patients worsens initial treatment response and is suggestive of poor long-term prognosis. The authors propose routine measurement of serum thyroid stimulating hormone (TSH) in all RA patients at the time of diagnosis and with yearly interval.
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Acknowledgements We thank Mrs. Maryam Mousavi for her contribution to data collection.
Disclosure of Interest None declared
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