THYROID ABNORMALITIES IN CHRONIC VIRAL-HEPATITIS AND THEIR RELATIONSHIP TO INTERFERON-ALFA THERAPY

The prevalence of antithyroid peroxidase antibodies (ATPO) and/or of t hyroid dysfunction was studied in 422 patients with chronic viral hepa titis C, B, and D. Baseline results were compared with those during an d 6 months after interferon alfa (IFN-alpha) therapy. The overall prev alence of ATPO among untreated patients was 14.1%, with no significant differences between chronic hepatitis C, B, or D, as well as between males and females. However, high ATPO titers (greater than or equal to 18 IU/mL) clustered significantly among females (8.7% vs, 3.4%; P = . 022), especially those with chronic hepatitis C (11.2% vs. 3.6%; P = . 036). Before treatment, 3.7% of the patients had thyroid dysfunction, mostly hypothyroidism (3.5%), the latter increasing to 14.3% among pat ients with ATPO titers greater than or equal to 18 IU/mL. IFN-alpha tr eatment significantly increased overall thyroid dysfunction (9.7%; P = .001) and hypothyroidism (7.8%; P = .01), particularly among patients with high baseline ATPO (38.5%; P = .0002). Six months after stopping IFN-alpha treatment, the prevalence of thyroid dysfunction was 8.0%, still significantly higher than at baseline. By multivariate analysis, the only predictor positively associated with pre- or on-treatment hy pothyroidism was the baseline titer of the ATPO antibodies (relative r isk [RR], 3.0 and 3.8 per each log titer increase, respectively). In c onclusion, patients with chronic viral hepatitis on IFN-alpha treatmen t exhibit an almost threefold increase of baseline thyroid dysfunction , persisting long after the end of therapy. High ATPO titers, clusteri ng among females, particularly those with hepatitis C, represent the o nly predictor of pre- and on-treatment hypothyroidism by multivariate analysis. Patients with chronic viral hepatitis, especially females, s hould be tested for ATPO and thyroid function and monitored during and posttreatment for free thyroxin (FT4) and thyroid-stimulating hormone (TSH) levels.