Objectives: To investigate the clinical and laboratory patterns of HCV-unrelated cryoglobulinaemic vasculitis (CV), and the factors influencing its outcome.
Methods: Prospective study of all anti-HCV and HCV-RNA negative patients with CV who have been observed since January 2004 in 17 centres participating in the Italian Group for the Study of Cryoglobulinaemias (GISC).
Results: 175 enrolled were followed up for 677 person-years. The associated conditions were primary Sjögren's syndrome (21.1%), SLE (10.9%), other autoimmune disorders (10.9%), lymphoproliferative diseases (6.8%), solid tumours (2.3%) and HBsAg positivity (8.6%), whereas 69 patients (39.4%) had essential CV. There were significant differences in age (p<0.001), gender (p=0.002), the presence of purpura (p=0.005), arthralgia (p=0.009), liver abnormalities (p<0.001), sicca syndrome (p<0.001), lymphadenopathy (p=0.003), splenomegaly (p=0.002), and rheumatoid factor titres (p<0.001) among these groups. Type II mixed cryoglobulins were present in 96 cases (54.9%) and were independently associated with purpura and fatigue (odds ratio [OR]4.3; 95% confidence interval [CI] 1.8-10.2; p=0.001; and OR2.8; 95%CI 1.3-6.3; p=0.012). Thirty-one patients died during follow-up, a mortality rate of 46/1000 person-years. Older age (for each additional year, adjusted hazard ratio [aHR] 1.13; 95%CI 1.06-1.20; p<0.001), male gender (aHR 3.45; 95%CI 1.27-9.40; p=0.015), type II MCG (aHR 3.31; 95%CI 0.09-1.38; p=0.047) and HBsAg positivity (aHR 7.84; 95%CI 1.20-36.04; p=0.008) were independently associated with greater mortality.
Conclusions: HCV-unrelated CV is a multifaceted and often disabling disorder. The associated conditions influence its clinical severity, giving rise to significantly different clinical and laboratory profiles and outcomes.