Impact of Preoperative Diabetes on Long-Term Survival After Curative Resection of Pancreatic Adenocarcinoma: A Systematic Review and Meta-Analysis

Background. Diabetes mellitus (DM) is coupled to the risk and symptomatic onset of pancreatic ductal adenocarcinoma (PDAC). The important question whether DM influences the prognosis of resected PDAC has not been systematically evaluated in the literature. We therefore performed a systematic review and meta-analysis evaluating the impact of preoperative DM on survival after curative surgery. Methods. The databases Medline, Embase, Web of Science, and the Cochrane Library were searched for studies reporting on the impact of preoperative DM on survival after PDAC resection. Hazard ratios and 95 % confidence intervals (CI) were extracted. The meta-analysis was calculated using the random-effects model. Results. The data search identified 4,365 abstracts that were screened for relevant articles. Ten retrospective studies with a cumulative sample size of 4,471 patients were included in the qualitative review. The mean prevalence of preoperative DM was 26.7 % (1,067 patients), and all types of pancreatic resections were considered. The meta-analysis included 8 studies and demonstrated that preoperative DM is associated with a worse overall survival after curative resection of PDAC (hazard ratio 1.32, 95 % CI 1.46-1.60, P = 0.004). Only 2 studies reported separate data for new-onset and long-standing DM. Conclusions. To our knowledge, this is the first metaanalysis evaluating long-term survival after PDAC resection in normoglycemic and diabetic patients, demonstrating a significantly worse outcome in the latter group. The mechanism behind this observation and the question whether different antidiabetic medications or early control of DM can improve survival in PDAC should be evaluated in further studies.