Assessment of liver fibrosis is important in determining prognosis and disease progression in patients with Chronic liver diseases and is need to choose the better treatment to apply. Although liver for determining the degree of liver fibrosis the biopsy is the gold standard, issues regarding invasiveness of this technique and small amount of liver tissue evaluated can limit its applicability and interpretation in clinical practice. To overcome these limitations, non-invasive methods to address liver fibrosis are being increasingly evaluated. These methods include serum markers such as the Enhanced Liver Fibrosis (ELF) test and elastography.
In our previous work, we found that the accuracy of a test based on the SWE was 0.77, in diagnostic liver fibrosis in patient with Metavir stages from F2 to F4, while the accuracy was 0.89 for patient with Metavir stage from F3 to F4 (19).
The aim of this work is to verify if the addition of the information provided by the ELF-test is able to improve the results obtained using SWE alone. To do this, we have built two scores based on the combination by SWE results with of ELF-test results: SCORE1 and SCORE2 realized using Metavir stages from F2 to F4 and to Metavir stage from F3 to F4, respectively.
The diagnostic accuracy obtained with SCORE1 was 0.79, not significantly higher than that obtained using the only SWE, but in return a significant enhancement of specificity was observed 92% vs 64% (p < 0.004). Similar results were obtained with SCORE2: the difference in the diagnostic accuracy was non significant ( 0.87 vs 0.89) while, an enhancement of specificity although non significant (95% vs 81%, p = 0.092) was observed. Our results are interesting because a highly specific test is to be used in a screening situations. The increased specificity reducing false positive results (20) reduces the number of subjects to be proposed for invasive diagnostic techniques or unnecessary therapies. Furthermore, a high specificity is also necessary to verify the presence of a disease that has little clinical evidence.
Our study partially confirms results from previously published studies. Katharina Staufer et al (21) have shown that for diagnosis of F2, F3, and F3 plus, respectively, receiver operating characteristic analysis revealed superior diagnostic accuracy of ELF score ( (AUC) 0.85, 0.90, 0.90), FibroMeterV2G (AUROC 0.86, 0.88, 0.89), FibroMeterV3G (AUROC 0.84, 0.88, 0.88), and LSM per protocol (AUROC 0.87, 0.95, 0.91) versus FIB-4 (AUROC 0.80, 0.82, 0.81) or NFS (AUROC 0.78, 0.80, 0.79). Proprietary fibrosis panels and VCTE show superior diagnostic accuracy for noninvasive diagnosis of fibrosis stage in NAFLD as compared to FIB-4 and NFS. Ragazzo et (22) showed good results for ELF with an AUROC of 0.707 and for ARFI an AUROCs of 0.67 for > F2, 0.74 for > F3, and 0.97 for F4.
Trembling PM et al. (23)evaluated performance of ELF and Transient Elastography (TE) in detecting liver fibrosis with reference to liver histology in a cohort of patients with CHB (n = 182), and compared the performance of these modalities. They demonstrated that, in patients with CHB, ELF has good performance in detection of liver fibrosis. Moreover, TE performs better in detection of severe fibrosis.
The main weak point of our work is the sample size. This limitation leads to high confidence intervals and the difficulty of distinguishing between two similar values of specificity or sensitivity. Therefore, further studies will be conducted in order to increase the sample size. This will allow to highlight further significant differences in order to distinguish the different levels of fibrosis. SWE and ELF-test can be performed with comparable diagnostic accuracy for non-invasive staging of liver fibrosis. The use of ELF-test and SWE in a combined score in a screening test increase the specificity for the prediction of histological fibrosis.