ACE and acute pancreatitis: The inclusion criteria for studies were as follows: (i) comparative observational studies (case-control or cohort); (ii) patients of all ages and genders; (iii) comparison of RAAS inhibitors, ACE inhibitors, or ARBs with a non-user or active control; and (iv) provision of effect estimates on the risk of acute pancreatitis (relative risk (RR), odds ratio (OR), or hazard ratio (HR)).