Mac-2-binding protein glycosylation isomer is useful to predict muscle cramps in patients with chronic liver disease.

Muscle cramps are frequently overlooked and worsen the quality of life in patients with chronic liver disease (CLD). Therefore, a valuable biomarker for predicting muscle cramps is required in the clinical setting. This study aimed to investigate whether the serum Mac-2-binding protein glycosylation isomer (M2BPGi) levels, a reliable liver fibrosis marker, could predict muscle cramps in patients with CLD. This retrospective study included 80 patients with CLD. Muscle cramps were assessed using a questionnaire regarding their presence, frequency, pain severity, and duration. The associated predictors were analyzed using logistic regression analysis. The diagnostic accuracy and optimal cutoff values were evaluated using receiver operating characteristic curves. Of the 80 patients, 55% had muscle cramps and showed significantly higher serum M2BPGi levels than those without them (4.54 cutoff index [COI] vs 2.20; P = .001). Multivariate analysis revealed that M2BPGi (odds ratio [ORs], 1.19; 95% confidence interval, 1.003-1.42; P = .046) was independently associated with the presence of muscle cramps. The optimal COI value for predicting muscle cramps was 3.95, and the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 61.4%, 80.6%, 79.4%, 63.0%, and 70.0%, respectively. Patients with a COI value ≥3.95 had a 2-fold higher incidence of muscle cramps than patients with a COI value <3.95 (79% vs 37%; P < .001). M2BPGi levels were also associated with the duration of muscle cramps. Serum M2BPGi appears useful as a biomarker for predicting muscle cramps in patients with CLD.