Eleven studies (213 patients) were included.
The validity scores of studies using 3 MU IFN ranged from 60 to 100. All but one study reported the PCR assay used. Only one study reported the lower limit of detection of the assay.
IFN dose 3 MU (8 studies, 152 patients).
The SVR in individual studies ranged from 19 to 68%, while the pooled SVR was 33% (95% confidence interval, CI: 21, 51). Significant heterogeneity was detected (P<0.0001). Four studies reported patients with SVR who developed a positive HCV viral load that was detected by PCR between 12 and 20 months after stopping IFN treatment (one of 3, three of 11, one of 13, and one of 13 patients converted after being SVR at 6 months). Forty-five (29.6%) of the 152 patients discontinued treatment due to adverse effects. The most common reasons were flu-like symptoms, leukopenia, depression and neurological symptoms. One study was terminated prematurely due to adverse effects.
For genotype 1 patients treated with 3 MU (6 studies), the pooled SVR was 26%.
In a separate analysis in which one outlying study was excluded, the pooled SVR was 31%.
The pooled SVR from 5 studies using IFN treatment for 6 months was 31%.
IFN dose greater than 3 MU (3 studies, 61 patients).
The studies suggested that higher doses of IFN did not increase SVR rates and might increase adverse effects. The SVR rates were 27% (at 5 months), 33% and 53%. Rates of withdrawal due to adverse effects were 33% (2 studies) and 35%.