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Chapter 3.1
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the presence of a confounding variable, which is also intermediate. The G-estimation
estimates the factor ψ. We use the exponent of -ψ, further referred to as E, as the factor
by which the time towards development of HCC would be expanded (or contracted
in case E is smaller than 1.0) if the treatment with glycyrrhizin would not have been
given (Appendix 1). This G-estimation was carried out with a macro written in SAS (SAS
Institute Inc, Cary, NC, USA).
RESULTS
Descriptives
A total of 1093 chronic hepatitis C patients with non-response to previous interferon
therapy were included in the study. Follow-up started at six months after the end-oftreatment.
During a mean follow-up of 6.1 years (SD 1.8) 26,450 visits were recorded.
The mean duration of follow-up was 6.3 years (SD 1.8) for patients who were treated with
glycyrrhizin and 6.0 years (SD 1.8) for patients who were not. Fifty-eight percent of the
patients were males and the median age at time of inclusion was 52 years (range 17-81).
Forty percent of the patients had acquired hepatitis C by blood transfusion. Further
patient characteristics are shown in table 1.
Table 1. Descriptives.
Overall Glycyrrhizin no glycyrrhizin p-value*
Number 1093 465 628
M/F (%) 628/455 (58/42) 262/198 (56/43) 366/257 (58/41) 0.67
Age, mean (range) 52.2 (17-81) 53.9 (29-80) 50.9 (17-81)