Noninvasive Markers Appear Useful in Predicting Fibrosis in HIV-HCV Coinfected Patients

By Brian Boyle, MD

While some non-invasive markers of hepatic fibrosis have been validated in HCV-monoinfected patients, limited data exist regarding the use of these assays in HIV/HCV coinfected patients. In a study presented at the 13th CROI, investigators validated 2 previously described models and  developed a novel index to predict significant fibrosis.

Correlates of significant fibrosis were evaluated among 218 patients in the Johns Hopkins HIV clinic who had a liver biopsy and complete data available. The goal of the analyses performed was to differentiate patients with no or minimal fibrosis from those with significant fibrosis. The models used were AST to platelet ratio index (APRI = AST/ULN)*100/platelet count) and FIB-4 (= age [years]* AST /(platelet count)*(ALT)½.) and the authors also attempted to develop their own predictive model.

The median age of the patients was 49 years; 67% were male; 83% black; 76% injecting drug users (IDU); 40% had clinically diagnosed alcohol abuse (past or active); the median CD4 cell count was 345/mm3 and median HIV RNA level was 309 copies/mL. Of 218 subjects, 55 (25%) had significant fibrosis and these patients were more likely to abuse alcohol, have higher ALT, AST and total bilirubin levels, and lower platelet count and albumin. Significant fibrosis was not associated with age, sex, hyperglycemia, antiretroviral use, CD4 cell count, or HIV RNA level.

Using a multivariate analysis, significant fibrosis was independently associated with an AST >1.25 x upper limit of normal (ULN), platelet count <150,000/mm3, albumin <3.5 g/dL and alcohol abuse. Using a regression model, the Johns Hopkins Fibrosis Index risk score was found to be –3.06 + 1.43 (if AST >1.25 x ULN, otherwise 0) + 1.3 (if platelet count <150,000; otherwise 0) + 0.81 (if albumin <3.5; otherwise 0) + 1.26 (if alcohol abuse; otherwise 0). Further, the Johns Hopkins Fibrosis Index, APRI and FIB-4 all appeared to be effective means for predicting liver fibrosis levels in HIV/HCV coinfected patients. 

The authors conclude, “In this urban, HIV clinic, categorical assessment of routine laboratory (albumin, AST and platelet count) and clinical data (alcohol abuse) accurately predicted significant fibrosis in HCV-infected adults. The utility of Johns Hopkins Fibrosis Index and other non-invasive models should be evaluated in other clinical settings. If validated, such indices may have a role in identifying patients with significant liver disease in settings in which access to liver biopsy is limited.

02/14/06

Reference
M S Sulkowski and others. Prediction of Significant Hepatic Fibrosis in HIV/HCV-co-infected Patients: Comparison of the FIB-4, APRI and Johns Hopkins Fibrosis Index. 13th Conference on Retroviruses and Opportunistic Infections. Denver, CO. February 5-8, 2006. Abstract 867.