INS and diabetes mellitus: It has been reported that insulin-treated diabetes is associated with increased postoperative mortality compared to non-insulin-treated diabetes after cardiac surgery; however, it is unclear whether this finding is applicable to non-cardiac surgery.<h4>Objective</h4>We aimed to assess the effects of insulin-treated and non-insulin-treated diabetes on short-term mortality after non-cardiac surgery.<h4>Methods</h4>Our study was a systematic review and meta-analysis of observational studies.