Q J Med 2004; 97: 499-506
QJM vol. 97 no. 8 © Association of Physicians 2004; all rights reserved.
Thyroid involvement in patients with overt HCV-related mixed cryoglobulinaemia
From the 1Department of Internal Medicine, University of Pisa; 2Rheumatology Unit, University of Modena, and 3Medical Division and 4Endocrinological Laboratory, Azienda Ospedaliera Pisana, Pisa, Italy
Received 31 October 2002 and in revised form 21 January 2004
Background: Mixed cryoglobulinaemia (MC), a systemic vasculitis associated with hepatitis C virus (HCV) infection in >90% of cases, is frequently complicated by multiple organ involvement. The prevalence of thyroid disorders in MC has not yet been studied.
Aim: To investigate the prevalence and clinical features of thyroid involvement in patients with HCV-associated MC (HCV + MC).
Design: Case-control study.
Methods: HCV + MC patients (n = 93, 17 men and 76 women, mean ± SD age 63 ± 10 years, mean disease duration 14 ± 7 years) consecutively referred to the Rheumatology Unit were matched by sex and age (± 2 years) to (i) 93 patients with chronic C hepatitis (CH) without MC and (ii) 93 healthy (HCV-negative) controls from the local population. Measurements included prevalence of hypo- or hyperthyroidism, thyroid autoantibodies, thyroid nodules and thyroid cancer.
Results: By McNemar's
2 test, the following thyroid abnormalities were significantly more frequent in HCV + MC patients than in HCV-negative controls: serum anti-thyroperoxidase autoantibody (AbTPO) (28% vs. 9%, p = 0.001); serum AbTPO and/or anti-thyroglobulin autoantibody (31% vs. 12%, p = 0.004); subclinical hypothyroidism (11% vs. 2%, p = 0.038); thyroid autoimmunity (35% vs. 16%, p = 0.006). Serum AbTPO were also significantly more frequent in HCV + MC patients than in CH controls (28% vs. 14%, p = 0.035).
Discussion: The prevalence of thyroid disorders is increased in patients with HCV-related mixed cryoglobulinaemia. We suggest careful monitoring of thyroid function in these patients.
Address correspondence to Dr A. Antonelli, Department of Internal Medicine, University of Pisa, via Roma, 67, 56100, Pisa, Italy. e-mail: a.antonelli{at}med.unipi.it