IDDF2021-ABS-0092 A diagnostic test meta-analysis evaluating the performance of imaging-based and blood biomarker-based assessment tools for fibrosis after liver transplantation

Abstract

<h3>Background</h3> Assessing fibrosis after liver transplant (LT) remains a core concern and can suggest the presence of de novo nonalcoholic fatty liver disease or recurrence after transplant. While biopsy remains the gold standard for assessing fibrosis, the acceptability of periodic fibrosis by patients remains a barrier for routine use. Noninvasive tests (NITs) can be used to assess fibrosis after LT. However, the diagnostic accuracy of these tests remains unknown after transplant. Hence, we seek to evaluate the accuracy of NIT after LT. <h3>Methods</h3> We conducted a systematic search of the literature in Medline and Embase on 15 June 2021. Articles relating to the use of vibration-controlled transient elastography (VCTE), 2D shear wave elastography (2DSWE), magnetic resonance elastography (MRE), acoustic radiation force impulse (ARFI), fibrotest, AST to Platelet Ratio Index (APRI), and the Fibrosis-4 Index (FIB-4) were included in the study. Evaluation of diagnostic accuracy was done with a bivariate binomial model, and comparisons between tests were established with likelihood ratio estimates. <h3>Results</h3> In total, 1,829 individuals were assessed for fibrosis using biopsy after liver transplant. 644 individuals had fibrosis of F2≥ (37.01%, CI: 28.78 - 46.07) F3≥ (16.85%, CI: 10.92 - 25.08), and F4 was and (9.93%, CI: 7.42 - 13.16) respectively. The results are summarized in (IDDF2021-ABS-0092 Table 1). In brief, AFRI and VCTE provided sufficient diagnostic accuracy at F2 and F3. VCTE was additionally suited for F4 diagnosis. Blood-based NIT was found to be an inaccurate measure of fibrosis. When comparisons were conducted between NITs, there was no significant difference between VCTE and AFRI at F2 and F3 in both sensitivity and specificity (IDDF2021-ABS-0092 Figure 1, IDDF2021-ABS-0092 Figure 2). Blood-based NIT was inferior to VCTE and AFRI. <h3>Conclusions</h3> To our knowledge, our study is the first systematic evaluation of NITs after transplant. The diagnostic accuracy suggests that VCTE and ARFI should be employed as measures of fibrosis after LT. The presence of thrombocytopenia after LT results in the reduced accuracy of FIB-4 and ARFI. More studies are required to assess other measures of NITs, including MRE.