Effects of Biologics on Fibrosis-4 Index in Patients with Psoriasis.

Background: Psoriasis is accompanied by systemic inflammation that includes the liver. The fibrosis-4 (FIB-4) index was developed to predict significant liver fibrosis. The present study evaluated the effects of biologics, including TNF inhibitors, on the FIB-4 index in psoriasis patients.

Methods: All adult patients with psoriasis who were prescribed biologics (TNF inhibitors, IL-17 inhibitors, or IL-23 inhibitors) at Nippon Medical School from June 2014 to January 2024 for the first time (biologic-naïve patients) were included in this study. The FIB-4 index was calculated before and after 6 months of treatment with biologics.

Results: A total of 105 patients were enrolled. The FIB-4 index was higher after 6 months of treatment with TNF inhibitors (P=0.0018) and IL-17 inhibitors (P=0.045) but did not change with IL-23 inhibitors. Aspartate aminotransferase and alanine aminotransferase levels did not change after treatment with TNF inhibitors, IL-17 inhibitors, or IL-23 inhibitors. Platelet count decreased after treatment with TNF inhibitors (P=0.0011) and IL-23 inhibitors (P=0.039) but did not change with IL-17 inhibitors.

Conclusions: Downregulation of platelets seems to be a major contributing factor for the increase in FIB-4 index in patients treated with TNF inhibitors. Although the FIB-4 index is a simple marker to screen for liver fibrosis, changes in this index should be interpreted with caution, and imaging findings such as transient elastography should also be used to evaluate the status of liver fibrosis.