Background: In the perioperative context, a frailty evaluation scale must consider certain characteristics such as validation, execution speed, simplicity, the capacity to measure multiple dimensions and not being dependent on a cognitive or physical test that could not be performed prior to surgery. The test should select patients that could benefit from interventions aimed to improve their postoperative outcomes. Aim: To validate two frailty evaluation scales for the perioperative period. Material and Methods: The Risk Analysis Index with local modifications (RAI-M) were applied to 201 patients aged 73 +/- 7years (49% women) and the Edmonton frailty scale were applied in 151 patients aged 73 +/- 7 years (49% women) in the preoperative period. Their results were compared with the Rockwood frailty index. Results: The Edmonton frail scale showed adequate psychometric properties and assessed multiple dimensions through 8 of the 11 original questions, achieving a discrimination power over 80% compared to the Rockwood Index. The RAI- M, demonstrated solid psychometric properties with a tool that examines 4 dimensions of frailty through 15 questions and reviewing the presence of 11 medical comorbidities. This scale had a discrimination power greater than 85% and it was significantly associated with prolongation of the planned hospital stay and mortality. Conclusions: RAI-M is a short and easily administered scale, useful to detect frailty in the preoperative period
