Golubovic 2018.

Study characteristics
General information	Objective  Added biomarkers, biomarkers compared, prediction model compared Journal BioMed Research International; Medical Principles and Practice Country Serbia Study design Prospective cohort study
Participants	Number of included patients 122 Surgical specialty Vascular surgery Age Mean 67 years (SD 4.5) Male sex 77% High‐risk surgery Not reported Insulin‐dependent diabetes mellitus 15.6% History of ischaemic heart disease 21.3% History of congestive heart failure Not reported History of cerebrovascular events 26.2% Elevated creatinine Not reported 0 RCRI factors Not reported 1 RCRI factor Not reported 2 RCRI factors Not reported 3 or more RCRI factors Not reported
Predictors	Predictor 1: V‐POSSUM Objective: added biomarker, biomarker compared Category: prediction model Scale: not applicable Threshold: not applicable Assay/device: not applicable   Predictor 2: NT‐proBNP Objective: added biomarkers, biomarker compared Category: blood Scale: continuous Threshold: not applicable Assay/device: chemiluminescence enzyme immunoassay technology (CLEIA) (Mitsubishi Chemical Europe GmbH, Düsseldorf, Germany)   Predictor 3: High‐sensitivity troponin I Objective: added biomarkers Category: blood Scale: continuous Threshold: not applicable Assay/device: Magtration5 technology on a PATHFAST Immunoanalyser (Mitsubishi Chemical Europe GmbH, Düsseldorf, Germany)   Predictor 4: V‐POSSUM + NT‐proBNP Objective: added biomarker Category: prediction model Scale: not applicable Threshold: not applicable Assay/device: chemiluminescence enzyme immunoassay technology (CLEIA) (Mitsubishi Chemical Europe GmbH, Düsseldorf, Germany)   Predictor 5: NT‐proBNP + high‐sensitivity troponin I Objective: added biomarkers, biomarker compared Category: blood Scale: continuous Threshold: not applicable Assay/device: chemiluminescence enzyme immunoassay technology (CLEIA) and Magtration5 technology on a PATHFAST Immunoanalyser (Mitsubishi Chemical Europe GmbH, Düsseldorf, Germany)   Predictor 6: V‐POSSUM + high‐sensitivity troponin I Objective: added biomarker, biomarker compared Category: prediction model Scale: not applicable Threshold: not applicable Assay/device: Magtration5 technology on a PATHFAST Immunoanalyser (Mitsubishi Chemical Europe GmbH, Düsseldorf, Germany)   Predictor 7: V‐POSSUM + NT‐proBNP + high‐sensitivity troponin I Objective: added biomarker, biomarker compared Category: prediction model Scale: not applicable Threshold: not applicable Assay/device: chemiluminescence enzyme immunoassay technology (CLEIA) and Magtration5 technology on a PATHFAST Immunoanalyser (Mitsubishi Chemical Europe GmbH, Düsseldorf, Germany)   Predictor 8: High‐sensitivity troponin I + high‐sensitivity CRP Objective: biomarker compared Category: blood Scale: continuous Threshold: not applicable Assay/device: Magtration5 technology on a PATHFAST Immunoanalyser (Mitsubishi Chemical Europe GmbH, Düsseldorf, Germany) and immunoturbidimetry method on a Beckman Coulter AU 680 analyser (Beckman Coulter Inc., Brea, CA, USA)   Predictor 9: High‐sensitivity troponin I + CK‐MB Objective: biomarker compared Category: blood Scale: continuous Threshold: not applicable Assay/device: Magtration5 technology on a PATHFAST Immunoanalyser (Mitsubishi Chemical Europe GmbH, Düsseldorf, Germany) and immunoturbidimetry method on a Beckman Coulter AU 680 analyser (Beckman Coulter Inc., Brea, CA, USA)   Predictor 10: NT‐proBNP + high‐sensitivity troponin I + high‐sensitivity CRP Objective: biomarker compared Category: blood Scale: continuous Threshold: not applicable Assay/device: chemiluminescence enzyme immunoassay technology (CLEIA) and Magtration5 technology on a PATHFAST Immunoanalyser (Mitsubishi Chemical Europe GmbH, Düsseldorf, Germany) and immunoturbidimetry method on a Beckman Coulter AU 680 analyser (Beckman Coulter Inc., Brea, CA, USA)
Outcome	Outcome category MACE Full outcome definition Acute myocardial infarction, cardiac arrhythmia, pulmonary oedema, acutely decompensated heart failure and cardiac arrest Prediction horizon 30‐day events and 90‐day events
Analysis	Number of outcomes 13 within 30 days and 29 within 90 days       Handling missing data Assumption of normal value if missing Discrimination reported? Yes Calibration reported? No   Reclassification reported? Yes
PROBAST: Applicability	Domain 1: Participant selection Low Justification:  Domain 2: Predictors Unclear Justification: no information on RCRI predictor definitions Domain 3: Outcome High Justification: definition of MACE varies from the development cohort (includes cardiac arrhythmias) Overall judgement High Justification: patients selected were generalisable to the patient population used in the RCRI development study. However, 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	Although only patients undergoing vascular surgery were included, participant selection was appropriate and the RCRI model can be applied in these patients.
Domain 2: Predictors	Unclear	No information on RCRI predictor definitions.
Domain 3: Outcome	Unclear	No information how the individual items of the composite outcome were defined and whether blinding occurred.
Domain 4:  Analysis	No	Low number of events, dichotomisation of continuous variable and no information on handling missing data.
Overall judgement	No	Patient selection was appropriate. There was no/unclear information on how predictors were defined/assessed. However, the number of outcomes was low and there was no information on missing data and no calibration was reported.