Diabetes Mellitus And Risk Of Cholangiocarcinoma:A Meta-analysis

Background: Cholangiocarcinoma(CCA),originates from the epithelium of the intrahepatic and extrahepatic biliary tree,is the second most common primary hepatobiliary carcinoma after hepatocellular carcinoma(HCC).Extrahepatic cholangiocarcinoma is further classified into perihilar cholangiocarcinoma(p CCA)and distal cholangiocarcinoma(d CCA)based on anatomical location.Cholangiocarcinoma is a highly malignant tumor with a very poor prognosis.Some case-control studies and cohort studies have been conducted to verify that diabetes is a risk factor for cholangiocarcinoma,but some studies have the opposite result.Objective: We conducted a systematic review and meta-analysis to evaluated the association between diabetes mellitus and cholangiocarcinoma.Methods: We conducted a comprehensive search of the literature included in the EMBASE,Pub Med,and Cochrane Library database before August 2018.The information were extracted from the included studies by two investigators work alone.The NewcastleOttawa Scale(NOS)scale was used to assess the quality of the included studies.The pooled relative risk(RR)with 95% confidence intervals(CI)were calculated by the Der Simonian-Laird method.The RR value greater than 1 indicates that the exposure factor is a protective factor for the disease.Conversely,the RR value of less than 1 indicates that the exposure factor is a risk factor for the disease.Results: A total of 1985 records were identified through database searching,twenty-five studies were eventually considered to meet the inclusion criteria.The meta-analysis indicated that diabetes increased risk of CCA(RR=1.74;95%CI 1.52-2.00).Diabetes mellitus was also associated with an 86%(RR=1.86;95%CI: 1.63-2.13)and a 76%(RR=1.76;95%CI: 1.54-2.02)increased risk of ICC and ECC,respectively.No significant publication bias was seen in any of the enrolled studies.Conclusion: Diabetes mellitus was considered a risk factor for cholangiocarcinoma by calculating the results of the meta-analysis,particularly in the ECC.