2026 The Journal of Rheumatology 2006; 33:10 Personal non-commercial use only. The Journal of Rheumatology Copyright © 2006. All rights reserved. High Prevalence of Thyroid Autoimmunity and Hypothyroidism in Patients with Psoriatic Arthritis ALESSANDRO ANTONELLI, ANDREA DELLE SEDIE, POUPAK FALLAHI, SILVIA MARTINA FERRARI, MARCO MACCHERONI, ELE FERRANNINI, STEFANO BOMBARDIERI, and LUCREZIA RIENTE ABSTRACT. Objective. To evaluate the prevalence of thyroid disorders in a group of patients with psoriatic arthritis (PsA). Methods. A complete thyroid investigation was carried out in 80 patients with PsA, in gender- and age- matched subjects (1:5) drawn from the general population (controls), and in 112 patients with rheuma- toid arthrtitis (RA) with similar iodine intake. Results. Anti–thyroid peroxidase antibodies (AbTPO), a hypoechoic thyroid, and subclinical hypothy- roidism were significantly more frequent in women with PsA than in control women, and their fre- quency was similar to that in patients with RA (positive AbTPO titer 28%, 12%, and 31%; hypoechoic thyroid 31%, 16%, and 36%; subclinical hypothyroidism 25%, 8%, and 12%, respectively). Among men, positive AbTPO titers and a hypoechoic thyroid were found more frequently in the patients with PsA and RA than in controls (positive AbTPO titer 14%, 5%, and 2%; hypoechoic thyroid 16%, 10%, and 3%, respectively). All patients with PsA with subclinical hypothyroidism had polyarticular involve- ment (p < 0.05) and a longer disease duration (years 19 ± 15 vs 11 ± 8, p = 0.03) than patients with euthyroid PsA. The prevalence of subclinical hyperthyroidism, thyroid nodules, and thyroid enlarge- ment was not significantly different among the 3 groups. Conclusion. Our results demonstrate a significantly higher prevalence of thyroid autoimmunity (posi- tive AbTPO, hyoechoic thyroid) findings in men and women with PsA and of subclinical hypothy- roidism in women with PsA than in the general population. Therefore, thyroid function tests, an AbTPO assay, and thyroid ultrasound should be performed as part of the clinical evaluation, particularly in women with PsA. (First Release Aug 1 2006; J Rheumatol 2006;33:2026–8) Key Indexing Terms: PSORIATIC ARTHRITIS RHEUMATOID ARTHRITIS THYROID AUTOIMMUNITY HYPOTHYROIDISM THYROID CANCER From the Department of Internal Medicine and the Rheumatology Unit, University of Pisa; and the Endocrinological Laboratory, Azienda Ospedaliera Pisana, Pisa, Italy. A. Antonelli, MD, Department of Internal Medicine; A. Delle Sedie, MD, Rheumatology Unit; P. Fallahi, MD; S.M. Ferrari, MD, Department of Internal Medicine, University of Pisa; M. Maccheroni, MD, Endocrinological Laboratory, Azienda Ospedaliera Pisana; E. Ferrannini, Professor, Department of Internal Medicine; S. Bombardieri, Professor; L. Riente, MD, Rheumatology Unit, University of Pisa. Address reprint requests to Dr. L. Riente, U.O Reumatologia, Dipartimento Medicina Interna, Via Roma 67, 56126 Pisa, Italy. E-mail: l.riente@int.med.unipi.it Accepted for publication May 18, 2006. Data regarding thyroid involvement in psoriatic arthritis (PsA) are lacking 1 . We therefore evaluated the prevalence of thyroid disorders in a group of patients with PsA. MATERIALS AND METHODS Study patients. Eighty patients with PsA (according to the criteria of Vasey and Espinoza) were recruited into the study 2 . Disease activity was assessed by American College of Rheumatology joint count, C-reactive protein level, health assessment questionnaire, duration of morning stiffness, and presence of spinal and nocturnal pain 3 . Control groups. We enrolled 2 control groups: (1) 112 patients with rheuma- toid arthritis (RA) according to American Rheumatology Association classi- fication criteria 4 ; and (2) and 400 control subjects whose level of iodine intake was known; each patient with PsA was matched by sex and age with 5 of these subjects, who were from a cohort of 1,640 residents living in the same geographic area. Subjects with a history of rheumatic diseases were excluded. Study protocol. All patients and controls underwent a complete clinical eval- uation. Thyroid sonography (Esaote AU5 with a sectorial 7.5 MHz transduc- er) was performed in all subjects by a single physician, blinded to laboratory findings, who evaluated the following: thyroid volume 5-7 ; thyroid tissue abnormalities, scored as reported by Antonelli, et al 6,7 ; and presence of thy- roid nodules. Biopsy samples were obtained from nodules with a diameter > 10 mm. Thyroid blood flow (TBF) was studied by color-flow Doppler (CFD). CFD pattern was defined according to Vitti, et al 8 . Serum levels of thyroid stimulating hormone (TSH) (RIA kit, DiaSorin, Stillwater, MN, USA), free triiodothyronine (FT 3 ), free thyroxine (FT 4 ) (RIA kits, Amerlex-Mab FT 3 /FT 4 Kit, Amersham, UK) and anti–thyroglobulin antibody (AbTg) and anti–thy- roid peroxidase antibody (AbTPO) titers (both by IRMA, ICN Pharma- ceuticals, Costa Mesa, CA, USA) were evaluated. The study was approved by the ethics committee and all subjects gave their informed written consent. Statistical analysis. Because of the different female:male ratios in the PsA and RA groups and since female gender is a well-recognized risk factor for thy- roid disorders, levels of TSH, FT3, FT4, AbTPO, and AbTg were compared only among participants of the same gender. Mean group values were com- pared using one-way analysis of variance (ANOVA) for normally distributed variables. Proportions were compared by the chi-squared test. Post hoc com- www.jrheum.org Downloaded on December 15, 2021 from