Noordzij 2006.

Study characteristics
General information	Objective  Added biomarkers      Journal American Journal of Cardiology Country The Netherlands Study design Retrospective cohort study
Participants	Number of included patients 28,457 Surgical specialty Noncardiac surgery Age Median 60.1 years (IQR = 49.1 to 71.2 years) Male sex Not reported High‐risk surgery 43.4%   Insulin‐dependent diabetes mellitus Not reported  History of ischaemic heart disease 2.7% History of congestive heart failure 0.6% History of cerebrovascular events Not reported  Elevated creatinine 0.6% 0 RCRI factors 95% 1 RCRI factor 4.3% 2 RCRI factors 0.6% 3 of more RCRI factors 0.1%
Predictors	Predictor 1: ECG abnormalities   Objective: added biomarkers  Category: imaging Scale: dichotomous Threshold: not applicable Assay/device: not applicable   Predictor 2: Age    Objective: added biomarker  Category: patient characteristic Scale: not reported Threshold: not applicable Assay/device: not applicable
Outcome	Outcome category Cardiovascular death Full outcome definition Not applicable Prediction horizon 30‐day events
Analysis	Number of outcomes 199 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 at high risk for CAD included Domain 2: Predictors High Justification: predictor definitions very different from the development study Domain 3: Outcome High Justification: outcome was cardiovascular death and not MACE Overall judgement High Justification: only a selected group of patients was included; predictors of the original RCRI were not included or had a different definition. In addition, the outcome definition used 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	No	Predictor definitions very different from the development study.
Domain 3: Outcome	Yes	Clearly defined outcome definitions and appropriate adjudication of outcomes.
Domain 4:  Analysis	No	No information on handling of missing data and calibration/reclassification not assessed.
Overall judgement	No	Patient selection was appropriate and outcomes was clearly defined and assessed. Predictor definitions were defined differently compared to the definitions used in the RCRI development study. Furthermore, there was no information on handling of missing data and inappropriate reporting of performance measures.