Epidemiology

Thyroid disorders common in patients with chronic hepatitis C

Last Updated: 2004-07-08 9:40:26 -0400 (Reuters Health)

By Will Boggs, MD

NEW YORK (Reuters Health) - Chronic infection with hepatitis C virus (HCV) is associated with an increased rate of hypothyroidism and thyroid autoimmunity, according to a report in the July 1st issue of The American Journal of Medicine.

"The significant association of chronic hepatitis C with hypothyroidism and thyroid autoimmune phenomena implies that these patients should be screened for thyroid function on a periodic basis," lead author Dr. Alessandro Antonelli from the University of Pisa School of Medicine, Italy, told Reuters Health. "A substantial proportion-13% in our series-will have hypothyroidism, and thus might benefit from treatment."

Thyroid involvement in HCV-infected patients has been reported previously, the authors explain, but little is known about the prevalence and nature of thyroid disorders in such patients.

Dr. Antonelli and colleagues investigated the prevalence and features of thyroid disorders in 630 consecutive patients with chronic hepatitis due to HCV infection.

Patients with chronic HCV infection had significantly higher thyroid stimulating hormone (TSH) and significantly lower free T3 and free T4 levels than did uninfected controls or hepatitis B virus-infected patients, the authors report.

Significantly more HCV-infected patients than controls had positive anti-thyroid peroxidase or anti-thyroglobulin autoantibodies, the results indicate, and hypothyroidism (TSH greater than 4 mIUnits/mL) was significantly more common among HCV-infected patients (13%) than among controls (3-5%).

Both markers of autoimmunity were more common in hypothyroid HCV-infected patients than in euthyroid HCV-infected patients, the researchers note.

"We are planning a population based epidemiological study to assess the association between thyroid disorders and HCV infection," Dr. Antonelli added. "The possible association of HCV infection with thyroid differentiated cancer and diabetes mellitus is under investigation not only in patients with HCV infection, but also in patients with HCV associated mixed cryoglobulinemia."

Am J Med 2004;117:10-13,60-61.