Evaluation of red cell distribution width-to-platelet ratio and other laboratory markers in staging Fontan-associated liver disease

Introduction
Fontan-associated liver disease (FALD) is a common complication in patients with Fontan circulation.

Aim
We aimed to evaluate the red blood cell distribution width-to-platelet ratio (RPR) index as a non-invasive marker for assessing FALD severity, given its reported usefulness in in conditions such as hepatitis.

Material and methods
This retrospective, cross-sectional study included adult Fontan patients. Laboratory tests, liver elastography, and hemodynamic parameters were analyzed.

Results
Fifty-six patients (24 females, 43%; median age 24 years, interquartile range [22–28]) were enrolled. Patients were grouped by liver stiffness (LS) stage: METAVIR ≤ F2 (22 patients, 39%) and > F2 (34 patients, 61%). The RPR index was significantly higher in the > F2 group (0.08 vs. 0.12, p = 0.02), along with FIB-4 (0.68 vs. 1.06) and APRI (0.36 vs. 0.57). RPR correlated positively with liver stiffness (r = 0.27), total bilirubin (r = 0.43), cystatin C (r = 0.36), and creatinine (r = 0.38) but not with NT-proBNP, pulmonary artery pressure, or maximal oxygen consumption. The ROC curve analysis for predicting LS > F2 showed an AUC of 0.74 (95% CI: 0.61–0.87), comparable to FIB-4. Moreover, in the logistic regression model that accounted for age, gender, height, body weight, and systemic chamber morphology, RPR showed a significant association with LS > F2, with an odds ratio indicating a 1.4-fold (95% CI: 1.1–1.7) increase for every 0.01-unit increase in RPR.

Conclusions
The RPR index is a simple, helpful tool for evaluating FALD severity in Fontan patients.