Sixteen studies (n=254 patients) were included in the review: two randomised controlled trials; three controlled trials; and 11 cohort studies. Sample sizes ranged from three to 78 patients.
Sustained virological response rate for all studies was 0.33 (95% CI 0.24 to 0.43, I2=57%; 15 studies). Summary drop-out rate was 23% (95% CI 14 to 33, I2=79%; number of studies unknown). The most frequently reported side-effects that interrupted treatment were haematological abnormalities (18%), gastrointestinal (14%), neurological (10%) and cardiovascular (10%). Influenza-type symptoms were common, but did not frequently lead to withdrawal.
Subgroup analysis resulted in sustained virological response rates that ranged from 0.20 (95% CI 0.08 to 0.32, I2=15%; four studies) for pegylated interferon alpha-2b patients to 0.25 (95% CI 0.19 to 0.31, I2=61%; 10 studies) for pegylated interferon alpha-2a patients. The highest sustained virological response rates were observed in controlled studies (sustained virological response 0.38, 95% CI 0.18 to 0.59, I2=66%; five studies). The summary drop out rate for the controlled studies was 15% (95% CI 3 to 26, I2=67%; five studies). Sensitivity analysis revealed an association between sustained virological response and publication year, time on dialysis, end-of treatment virological response and end-of treatment biological response.