Reduced glomerular filtration rate is associated with poor sustained response rates to IFN/ribavirin in chronic hepatitis C

Background an Aims: Ribavirin is mainly eliminated from serum through renal clearance. The present study investigated the influence of glomerular filtration rate on sustained virological response in HCV patients treated with ribavirin.

Patients and Methods: A total of 341 consecutive patients treated with standard interferon and ribavirin (n=172) or pegylated interferon and ribavirin (n=169) were enrolled. GFR was calculated according to the Cockroft-Gault equation and categorised according to the KDOQI classification.

Results: A reduced GFR below 90ml/min/1.73m² was found in 36.1% of the patients, only 4.4% had a GFR below 60ml/min/1.73m². Baseline data (Age, gender, viral load, genotype distribution and cirrhosis prevalence did not differ between patients with normal GFR and those with reduced GFR. SVR was significantly lower in HCV patients with reduced GFR compared to those with normal GFR (33.3% vs. 47.2%; p<0.02), the rate of ribavirin reduction was 20.2 vs. 10.9% (p<0.03) and the incidence of anemia was 88.4 vs. 78.% (p<0,05). The cumulative ribavirin dose was 229±11mg in patients with reduced GFR vs. 255±11mg in patients normal GFR (p<0.15). Cumulative PEG-IFN dose was 4800±352µg in patients with reduced GFR and 5400±242µg in patients with normal GFR (p<0.15). In a multivariate analysis GFR (cutoff 90ml/min/1.73m²) appear to influence outcome of combination treatment (p<0.08; 95%CI: 1.07–2.67) besides HCV genotype and pretreatment viral load.

Conclusions: Reduced GFR is a negative predictor for SVR in patients with chronic hepatitis C treated with (PEG)-IFN /ribavirin. Suboptimal ribavirin and /or IFN dose due to a higher rate of anemia leading more frequent dose reductions might be one explanation for the poorer SVR rates among patients with impaired GFR.

SVR - chronic hepatitis C - interferon - therapy