The Roles of Fibrosis Index Based on Four Factors and Aspartate Transaminase-to-Platelet Ratio Index Scoring Systems as an Alternative to Transient Elastography Liver Stiffness in Liver Fibrosis Staging in Human Immunodeficiency Virus and Hepatitis C Virus Co-Infected Patients.

Background: Liver biopsy used to be the gold standard to assess liver fibrosis in patients infected with hepatitis C virus (HCV). Nonetheless, due to its invasive nature, techniques such as transient elastography liver stiffness (TE-LS), fibrosis index based on four factors (FIB-4) and aspartate transaminase-to-platelet ratio index (APRI) scores are currently being used. FIB-4 and APRI scores have the advantage of low cost and are readily available, compared with TE-LS. Herein, we evaluated the diagnostic performance of these scoring systems as compared to TE-LS in assessing liver fibrosis in patients with human immunodeficiency virus (HIV) and HCV co-infection.

Methods: The medical records of patients with HIV and HCV co-infection who had TE-LS done at our facility between August 1, 2013 and January 1, 2020 were extracted and analyzed. Exclusion criteria include: 1) patients co-infected with hepatitis B virus; 2) invalid TE-LS assessment; 3) have ≥ 10th upper limit of normal (ULN) alanine aminotransferase (ALT) levels; and 4) excessive alcohol use. Patient demographics, medical history, biochemical and clinical data were retrieved. For each patient, we calculated the FIB-4 and APRI score. Descriptive analysis was performed and correlation of FIB-4 and APRI with TE-LS was assessed with GraphPad Prism statistical software.

Results: Five hundred forty-seven patients underwent TE-LS during the study period. After excluding those without complete laboratory parameters, the total study population was 344. Their age was 56 ± 10.4 years and 234 (68%) were male. The average aspartate aminotransferase (AST) and ALT were 27.95 and 30.73. The average platelet count was 224 and the average TE-LS was 7.29. Fourteen patients (4.1%) had TE-LS values between 9 and 11.9 kPa and were classified as F3, while 29 (8.5%) had TE-LS ≥ 12 kPa and were classified as F4. With the correlation analysis, both APRI (correlation coefficient, r = 0.1097, 95% confidence interval (CI) 0.0403 - 0.2130; P = 0.042) and FIB-4 (r = 0.0424, 95% CI -0.0634 - 0.1474; P = 0.4335) were not correlated with TE-LS stages of fibrosis.

Conclusion: In our cohort, we failed to demonstrate that APRI and FIB-4 are reliable alternatives for screening liver fibrosis in patients with HIV and HCV co-infection. Nonetheless, APRI score still has a potential role as a screening tool instead of TE-LS measurement, which is costly and not readily available. It will be important to corroborate these findings in another large cohort, since this may have an important impact on patient management.