## 4 Discussion
trial in patients undergoing simeprevir combined with pegINF and RBV, similar results were obtained (after FU24 LS decreased by 14%) using the acoustic radiation force impulse elastography technique [41]. It can be hypothesized that the differences were influenced by the applied treatment (pegINF vs non-interferon therapies) and the method used to measure LS. The effect on the above results in our study may be due to the relatively high percentage of patients with liver cirrhosis, as well. In our study, statistically significant changes in LS were observed in patients with more advanced liver fibrosis at F3 and F4 (\(p\) = 0.02 and 0.0004 respectively). Higher levels of liver stiffness before treatment and greater LS reduction after treatment in treatment experienced patients was related to more advanced disease in this population compared to treatment naive. In previous studies, in patients treated with pegIFN in whom fibrosis was evaluated by liver biopsy, fibrotic regression was observed in long-term observation [42; 43; 44; 45]. In these studies, fibrosis declined by 29-82% depending on the time of observation (from 1.6 to 5.2 years). In the [PERSON] et al. study it was found that in 76% of patients who had F3-F4 fibrosis by liver biopsy prior to treatment, deduced fibrosis was reduced by 2 points in the fibrotic scale, and 46% of these patients had a reduction in fibrosis to F0-F1 (measured LS after treatment) [37]. It can be assumed that the LS changes not only illustrate the decline of the inflammatory process in the liver but also the regression of fibrosis and the LS measurement can visualize it in a faster way than the liver biopsy. In previous studies, it has already been confirmed that as a result of antiviral treatment, there is an improvement in some parameters that assess liver function. In the [PERSON] et al. study, they found that in patients who achieved SVR, a reduction in the AFP level, ALT activity, and platelet count were observed [46]. In a larger group of patients, in a more detailed analysis, this observation was confirmed by [PERSON] et al. [40]. In our group of patients, we found improvement in albumin and ALT levels. However, the level of platelets did not change significantly, which is in contrast to some of the previous studies [35; 40]. Probably due to the transient hyperbilirubinemia associated with the treatment (OMB/PRV/rtv \(\pm\) DSV \(\pm\) RBV), a statistically significant decrease in the level of bilirubin between baseline and FU24 and FU96 was observed. A similar decrease in bilirubin was observed by [PERSON] et al. [47]. One of the limitations of elastography is the effect on aminotransferase activity, or severity of inflammation. In our study we found that patients with advanced inflammation and ALT above 100 U/L had a statistically greater LS change between baseline and FU96, which is consistent with previous studies [40; 47; 48]. We also found, similarly to [PERSON] et al., a positive correlation between the size of LS change and ALT activity between baseline and FU96 [35]. HCV is a well-known viral carcinogen, causing a high risk of HCC development in the infected liver. A well-established marker of this type of cancer is AFP. In our study, the elevated level of AFP at baseline indicates in most patients the presence of inflammation and necrotic processes in the liver and the accompanying processes of parenchymal reconstruction related to advanced fibrosis. During the follow-up at the end of treatment there was a statistically significant decrease in AFP concentration compared to baseline during EOT from \(-0.96\) to \(88.35\) ng/dL, and during FU24 from \(-2.26\) to \(89.31\) ng/dL. It should be noted that the concentration of AFP stabilized in the period between FU24 and FU96. We did not find any statistically significant differences in the BMI index. In various studies, the results are ambiguous. [PERSON] et al. observed a statistically significant increase in BMI, while in the study by [PERSON] et al. there was no such relationship [35; 49]. [PERSON] et al.