Clinical efficacy of Mac-2-binding protein glycosylation isomer as a biomarker for albumin-bilirubin grade and the Controlling Nutritional Status score in chronic liver disease: investigation of cut-off values by the type of chronic liver disease.

Background: Mac-2-binding protein glycosylation isomer (M2BPGi), a novel noninvasive biomarker for fibrosis, is a prognostic factor for liver disease; however, its relationship with hepatic function reserve and nutritional status remains unclear. Furthermore, the cut-off value of this marker varies with the underlying liver disease. This study aims to clarify that M2BPGi can be clinically used as a hepatic function reserve marker and nutritional index without pushing the search for alternative markers to the forefront in clinical practice as an important biomarker.

Methods: Seven hundred and forty-three outpatients with chronic liver disease (CLD) were enrolled. We evaluated the relationship among M2BPGi, albumin-bilirubin (ALBI) grade, and Controlling Nutritional Status (CONUT) score as nutritional status markers. Diagnostic performance of M2BPGi values in distinguishing different modified ALBI (mALBI) grade and CONUT score were compared using receiver operating characteristic (ROC) curve analysis.

Results: The M2BPGi level increased with ALBI and mALBI grades. The correlation coefficient (r2) between M2BPGi and ALBI grade was 0.40 (r=0.63), indicating a positive correlation between M2BPGi and ALBI grade. The cut-off for M2BPGi to predict mALBI G1 vs. G2-G3 was 1.07, G1-2a vs. G2b-3 was 1.73, and mALBI G1-2 vs. G3 was 5.83 under the ROC curves. The cut-off for M2BPGi to predict CONUT score normal vs. light-severe was 1.60, normal-light vs. moderate-severe was 1.74, and normal-moderate vs. severe was 5.83 under the ROC curves. M2BPGi correlates with ALBI grade and is useful for diagnosing ROC analysis results, especially G2 and above. M2BPGi also correlates with the CONUT score and is useful for diagnosing ROC analysis results, especially moderate or higher. These results showed similar diagnostic performance regardless of the etiology of the background liver disease.

Conclusions: Although the predictive cut-off value varied with the type of liver disease, M2BPGi was found to be a single predict biomarker of ALBI and CONUT, and thus, is an effective indicator of CLD status. Further investigation is warranted to determine the clinical utility of this marker.