Farina‐Castro 2020.

Study characteristics
General information	Objective  Biomarkers compared, prediction model compared Journal Journal of Vascular Surgery Country Spain Study design Retrospective cohort study
Participants	Number of included patients 244 Surgical specialty Noncardiac surgery Age Median 91 years (IQR = 90 to 93) Male sex 39.3% High‐risk surgery Not reported Insulin‐dependent diabetes mellitus Not reported History of ischaemic heart disease Not reported History of congestive heart failure Not reported History of cerebrovascular events Not reported Elevated creatinine Not reported 0 RCRI factors 5.7% 1 RCRI factor 31.1% 2 RCRI factors 32.8% 3 or more RCRI factors 30.3%
Predictors	Predictor 1: ASA Objective: biomarker compared Category: patient characteristic Scale: categorical Threshold: not applicable Assay/device: not applicable   Predictor 2: S‐MPM (surgical mortality probability model) Objective: prediction model compared Category: prediction model Scale: not applicable Threshold: not applicable Assay/device: not applicable   Predictor 3: Charlson Comorbidity Index Objective: prediction model compared Category: prediction model Scale: not applicable Threshold: not applicable Assay/device: not applicable   Predictor 4: Reiss Index Objective: prediction model compared Category: prediction model Scale: not applicable Threshold: not applicable Assay/device: not applicable
Outcome	Outcome category All‐cause mortality; Comprehensive Complication Index ≥ 1 Full outcome definition Not applicable Prediction horizon 30 days all‐cause mortality and prediction horizon for Comprehensive Complication Index ≥ 1 was not reported
Analysis	Number of outcomes 66 deaths and 179 complications      Handling missing data No information on handling missing data Discrimination reported? Yes Calibration reported? No Reclassification reported? No
PROBAST: Applicability	Domain 1: Participant selection High Justification: only patients with age > 90 years were included Domain 2: Predictors Unclear Justification: the definition of each item of RCRI was unclear Domain 3: Outcome High Justification: outcome is all‐cause mortality or Comprehensive Complication Index, which is different from the definition from the development study (MACE) Overall judgement High Justification: only a selected group of patients was included, there was no/unclear information on predictor definitions and outcome definition was different compared to the development study
Notes	—
Item	Authors' judgement	Support for judgement
Domain 1: Participant selection	Yes	Appropriate participant selection in which patients were selected in whom the RCRI model can be applied.
Domain 2: Predictors	Unclear	The definition of each item of RCRI was unclear.
Domain 3: Outcome	Yes	Clearly defined outcome definitions and appropriate adjudication of outcomes.
Domain 4:  Analysis	No	Low number of outcomes, complete case analysis and no information on calibration and reclassification.
Overall judgement	No	Patient selection and outcome definitions with their assessment was appropriate. However, there was no/unclear information on predictor definitions. In addition, the number of outcomes was low, complete case analysis was performed and no calibration and reclassification measures were reported.