Background
Diabetes mellitus has been associated with increased risk of pancreatitis in several studies, however, not all studies have found an association. We conducted a systematic review and meta-analysis of prospective studies on diabetes mellitus and pancreatitis to clarify the association.

Methods
PubMed and Embase databases were searched for studies on diabetes mellitus and pancreatitis up to 8th of January 2020. Cohort studies that reported adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) for the association between diabetes diagnosis and pancreatitis were included and summary RRs (95% CIs) were calculated using a random effects model.

Results
Eight cohort studies were included in the meta-analysis, and seven of these were included in the analysis of diabetes mellitus and acute pancreatitis (14124 cases, 5.7 million participants). Comparing diabetes patients with persons without diabetes the summary RRs (95% CIs) were 1.74 (95% CI: 1.33–2.29, I2 = 95%) for acute pancreatitis, 1.40 (95% CI: 0.88–2.22, I2 = 0%, n = 2) for chronic pancreatitis, and 1.39 (95% CI: 1.07–1.80, I2 = 54%, n = 3) for pancreatitis overall. Although there was some indication of publication bias in the analysis of acute pancreatitis this appeared to be explained by one outlying study which when excluded did not substantially alter the association. The results persisted in several subgroup and sensitivity analyses.

Conclusions
These results suggest that diabetes patients are at an increased risk of acute pancreatitis. Further studies are needed on diabetes and risk of chronic pancreatitis, pancreatitis overall and on gallstone-related and non-gallstone-related pancreatitis.