RDW to Platelet Ratio: A Novel Noninvasive Index for Predicting Hepatic Fibrosis and Cirrhosis in Chronic Hepatitis B

OBJECTIVE To develop a simple predictive model for significant fibrosis and cirrhosis in chronic hepatitis B (CHB) using the routine hematological parameters of a complete blood count. METHODS A total of 458 eligible CHB patients who had undergone a liver biopsy were randomly divided into two cohorts: an estimation group (n = 310) and a validation group (n = 148). Liver histology was assessed according to the Metavir scoring scheme. All common demographics, hematological parameters, HBeAg status, HBV DNA, and liver biochemistry were analyzed. RESULTS Based on routinely available clinical parameters (age, sex, HBeAg status, HBV DNA, common hematological parameters of a complete blood cell count), a model for predicting significant fibrosis (Metavir score ≥2) in the estimation group was derived using platelets and red cell distribution width (RDW), and another model for predicting cirrhosis (Metavir score = 4) was derived using platelets, RDW and hemoglobin. A novel index, the RDW to platelet ratio (RPR), was developed to amplify the opposing effects of liver fibrosis on the RDW and platelets. The AUCs of the RPR for predicting significant fibrosis and cirrhosis were 0.825 and 0.884, respectively, which is superior to the AAR, FIB-4 and APRI in the estimation group. Compared with the two derived models, the RPR has a comparable predictive power for significant fibrosis and cirrhosis. Using optimized cutoffs (0.10 and 0.16), the RPR accurately predicted 63.1% of cases with significant fibrosis and 73.7% of cases with cirrhosis and accurately excluded 85.5% of the cases with mild fibrosis and 93.0% of the cases with no cirrhosis. CONCLUSION The RPR, a routinely available, inexpensive and easily calculated index, can predict significant fibrosis and cirrhosis in CHB patients with relatively high accuracy. The application of this index may reduce the need for liver biopsy in CHB patients.