L Croce1,2,3, L De Martinis1, S Pinto1, F Coperchini1, G Dito1, G Bendotti1, D Pasquali4, C Cappelli5, F Latrofa6, F Magri1,2, L Chiovato7,8, M Rotondi1,2. 1. Unit of Internal Medicine and Endocrinology, Laboratory for Endocrine Disruptors, Istituti Clinici Scientifici Maugeri IRCCS, 27100, Pavia, Italy. 2. Department of Internal Medicine and Therapeutics, University of Pavia, 27100, Pavia, Italy. 3. PhD Course in Experimental Medicine, University of Pavia, 27100, Pavia, Italy. 4. Department of Advanced Medical and Surgical Science, A.O.U. Vanvitelli, University of Campania "Luigi Vanvitelli", 80138, Naples, Italy. 5. Department of Clinical and Experimental Sciences, University of Brescia, 25123, Brescia, Italy. 6. Department of Clinical and Experimental Medicine, University of Pisa, 56124, Pisa, Italy. 7. Unit of Internal Medicine and Endocrinology, Laboratory for Endocrine Disruptors, Istituti Clinici Scientifici Maugeri IRCCS, 27100, Pavia, Italy. luca.chiovato@icsmaugeri.it. 8. Department of Internal Medicine and Therapeutics, University of Pavia, 27100, Pavia, Italy. luca.chiovato@icsmaugeri.it.
Abstract
PURPOSE: Serum-negative-chronic-autoimmune-thyroiditis (SN-CAT) is considered a milder variant of classic Hashimoto's thyroiditis (CHT). However, its prevalence remains unknown and it is still unclear whether SN-CAT behaves differently in terms of L-thyroxine (LT4) substitution treatment of hypothyroidism. Aims of this study were to estimate the prevalence of SN-CAT in a large series of hypothyroid patients and to compare LT4 requirements in hypothyroid patients with SN-CAT and CHT. METHODS: Five-hundred-eighty-one consecutive patients with primary-autoimmune-hypothyroidism were enrolled in a cross-sectional study. LT4 requirements and thyroid-volume changes were longitudinally evaluated in 49 hypothyroid patients with SN-CAT and in 98 sex and age-matched hypothyroid patients with CHT. RESULTS: In our series the prevalence of SN-CAT was 20.8%. At diagnosis, patients in the CHT and SN-CAT groups had similar male/female ratio, age and BMI, while serum TSH and thyroid-volume were significantly greater in the CHT group. In the longitudinal study, during a follow-up of 8.9 ± 4.6 years, 8 out of 49 (16.3%) SN-CAT patients developed positive tests for of circulating TPO-Ab and/or Tg-Ab. Thyroid-volume significantly decreased in CHT patients, but not in those with SN-CAT. The maximum daily substitution dose of LT4 was smaller in SN-CAT patients as compared with the CHT ones. Multivariate analysis showed that age, BMI, basal TSH and thyroid antibody status independently and significantly predicted the maximum daily substitution dose of LT4. CONCLUSIONS: SN-CAT accounts for a significant proportion of patients with autoimmune hypothyroidism. Compared with hypothyroid patients diagnosed with CHT, the SN-CAT ones require smaller doses of LT4 to correct their hypothyroidism.
PURPOSE: Serum-negative-chronic-autoimmune-thyroiditis (SN-CAT) is considered a milder variant of classic Hashimoto's thyroiditis (CHT). However, its prevalence remains unknown and it is still unclear whether SN-CAT behaves differently in terms of L-thyroxine (LT4) substitution treatment of hypothyroidism. Aims of this study were to estimate the prevalence of SN-CAT in a large series of hypothyroidpatients and to compare LT4 requirements in hypothyroidpatients with SN-CAT and CHT. METHODS: Five-hundred-eighty-one consecutive patients with primary-autoimmune-hypothyroidism were enrolled in a cross-sectional study. LT4 requirements and thyroid-volume changes were longitudinally evaluated in 49 hypothyroidpatients with SN-CAT and in 98 sex and age-matched hypothyroidpatients with CHT. RESULTS: In our series the prevalence of SN-CAT was 20.8%. At diagnosis, patients in the CHT and SN-CAT groups had similar male/female ratio, age and BMI, while serum TSH and thyroid-volume were significantly greater in the CHT group. In the longitudinal study, during a follow-up of 8.9 ± 4.6 years, 8 out of 49 (16.3%) SN-CATpatients developed positive tests for of circulating TPO-Ab and/or Tg-Ab. Thyroid-volume significantly decreased in CHT patients, but not in those with SN-CAT. The maximum daily substitution dose of LT4 was smaller in SN-CATpatients as compared with the CHT ones. Multivariate analysis showed that age, BMI, basal TSH and thyroid antibody status independently and significantly predicted the maximum daily substitution dose of LT4. CONCLUSIONS: SN-CAT accounts for a significant proportion of patients with autoimmune hypothyroidism. Compared with hypothyroidpatients diagnosed with CHT, the SN-CAT ones require smaller doses of LT4 to correct their hypothyroidism.
Authors: G Corona; L Croce; C Sparano; L Petrone; A Sforza; M Maggi; L Chiovato; M Rotondi Journal: J Endocrinol Invest Date: 2021-05-25 Impact factor: 4.256