Value of baseline IgM level in predicting the treatment response of primary biliary cholangitis / 临床肝胆病杂志

ABSTRACT

Objective To investigate the association between baseline IgM level and treatment response to ursodeoxycholic acid (UDCA) in patients with primary biliary cholangitis (PBC). Methods A retrospective analysis was performed for the clinical data of 637 PBC patients who were diagnosed and treated with UDCA for the first time in The Fifth Medical Center of Chinese PLA General Hospital from January 2010 to January 2020. The PBC patients were divided into UDCA complete response group with 436 patients and UDCA poor response group with 201 patients, and baseline clinical data were compared between the two groups. According to the optimal cut-off value of IgM determined by the area under the ROC curve (AUC) of baseline indices in predicting the risk of poor treatment response, the patients were divided into IgM ≥1.5×ULN group and IgM < 1.5×ULN group, and baseline parameters, treatment response, and prognostic model score were compared between groups. The t -test was used for comparison of normally distributed continuous data between two groups, and the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups; the chi-square test was used for comparison of categorical data between two groups. The Cochran-Mantel-Haenszel test was used for subgroup analysis, and forest plots were plotted for related risk values. Results Compared with the UDCA complete response group, the UDCA poor response group had significantly higher proportion of patients with liver cirrhosis, levels of total bilirubin, aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bile acid, total cholesterol (TC), IgA, and IgM, and positive rate of anti-Gp210 antibody at baseline ( χ 2 =4.596, Z =-9.932, -8.931, -8.361, -7.836, -4.694, -3.242, and -2.115, χ 2 =15.931, all P < 0.05). The UDCA poor response group had significantly higher Mayo Risk Score, Globe score, and UK-PBC risk score than the UDCA complete response group ( t =4.092, Z =-10.910 and -11.646, all P < 0.001). Compared with the normal IgM group, the elevated IgM group had significantly higher levels of AST, ALP, TC, IgA, and IgG and a significantly higher positive rate of anti-Gp210 antibody ( Z =-3.774, -5.063, -4.344, -2.051, and -6.144, χ 2 =25.180, all P < 0.05). IgM had an AUC of 0.552 in predicting poor treatment response. Compared with the IgM < 1.5×ULN group, the IgM ≥1.5×ULN group had significantly higher levels of AST, ALP, TC, and IgG, a significantly higher positive rate of anti-Gp210 antibody, and a significantly higher poor UDCA response rate ( Z =-4.193, -5.044, -3.250, and -5.465, χ 2 =25.204 and 8.948, all P < 0.05). IgM ≥1.5×ULN had an odds ratio of 1.416 (95% confidence interval [ CI ] 1.129-1.776, P =0.003) in predicting poor response. The subgroup analysis showed that for patients without liver cirrhosis, IgM ≥1.5×ULN had an odds ratio of 1.821 (95% CI 1.224-2.711, P =0.003) in predicting poor response. Conclusion Baseline IgM level has an important value in predicting UDCA response. IgM level should be closely monitored during treatment in PBC patients with a high baseline IgM level, and second-line drugs should be given in time if the abnormality persists.