Antiviral therapy for hepatitis C virus--associated mixed cryoglobulinemia vasculitis: a long-term followup study.

To evaluate the long-term efficacy of anti-hepatitis C virus (HCV) therapy in patients with HCV-associated mixed cryoglobulinemia (HCV-MC) vasculitis and to assess the factors associated with clinical remission of MC. This was a single-center study of 72 consecutive patients who received treatment with IFN alfa-2b (3 million IU 3 times a week; n = 32 patients) or PEGylated IFN alfa-2b (PEG-IFN alfa-2b) (1.5 mug/kg/week; n = 40 patients), both in combination with oral ribavirin (600-1,200 mg/day), for at least 6 months. Logistic regression was used to assess factors associated with clinical remission of MC. The mean +/- SD duration of followup after discontinuation of antiviral therapy was 39.7 +/- 24.4 months. Eight deaths (11.1% of patients) occurred during the study, primarily as a result of cardiovascular disease, liver disease, or infection. A complete clinical response of the MC occurred in 45 patients (62.5%), a sustained virologic response occurred in 58.3%, and cryoglobulins cleared in 45.8%. Compared with patients treated with IFN alfa-2b plus ribavirin, those receiving PEG-IFN alfa-2b plus ribavirin had a higher sustained clinical (67.5% versus 56.3%), virologic (62.5% versus 53.1%), and immunologic (57.5% versus 31.3%) response, regardless of HCV genotype and viral load. In multivariate analyses, an early virologic response (odds ratio 3.53 [95% confidence interval 1.18-10.59]) was independently associated with a complete clinical response of MC. A glomerular filtration rate <or=70 ml/minute (odds ratio 0.18 [95% confidence interval 0.05-0.67]) was negatively associated with a complete clinical response of MC. PEG-IFN alfa-2b plus ribavirin should be considered as induction therapy for HCV-MC vasculitis. An early virologic response and the absence of renal insufficiency are the key factors in the clinical response.