Long-term predictors of survival in essential mixed cryoglobulinemic glomerulonephritis

We report the clinical outcome of 105 essential mixed cryoglobulinemia (EMC) patients with renal involvement collected throughout 25 years in three renal Units of Milan. The median follow-up was 72 months since renal biopsy and 131 months since the clinical onset of EMC. Patient survival was 49% at 10 years after renal biopsy. Forty-two patients died primarily from cardiovascular and liver disease or infection, whereas 15 patients developed chronic renal failure. Two patients had a complete remission of the disease while 15 had a remission only of renal signs. Thirty-one patients are alive with persistent renal and extrarenal manifestations. Anti-HCV antibodies were retrospectively detected in 34 patients and were present in 85% of them. This variable was not included in the statistical evaluation. At multivariate analysis, age older than 50 years, purpura, splenomegaly, cryocrit levels higher than 10%, C3 plasma levels lower than 54 mg/dl, and serum creatinine higher than 1.5 mg/dl were independent risk factors for death or dialysis. In conclusion, several factors may influence the outcome of patients with EMC nephritis. Markers of disease activity and an impaired renal function can herald a bad prognosis. It should be stressed, however, that only a minority of patients eventually develop renal failure, probably because in the most severe cases patients die earlier.