Boersma 2005.

Study characteristics
General information	Objective  Added biomarkers Journal American Journal of Medicine Country Netherlands Study design Retrospective cohort study
Participants	Number of included patients 108,593 Surgical specialty Noncardiac surgery Age Not reported Male sex 48.2% High‐risk surgery 27.1% Insulin‐dependent diabetes mellitus Not reported History of ischaemic heart disease 3.3% History of congestive heart failure 1.3%  History of cerebrovascular events 0.5% Elevated creatinine 1.7% 0 RCRI factors 69.4% 1 RCRI factor 26.6% 2 RCRI factors 3.1% 3 or more RCRI factors 0.9%
Predictors	Predictor 1: Type of surgery + laparoscopic procedure + emergency surgery  Objective: added biomarker Category: patient characteristic  Scale: categorical  Threshold: type of surgery = 4 categories according to the American Heart Association Assay/device: not applicable   Predictor 2: Type of surgery + type of surgery + laparoscopic procedure + emergency surgery + age Objective: added biomarker Category: patient characteristic  Scale: categorical Threshold: type of surgery = 4 categories according to the American Heart Association Assay/device: not applicable
Outcome	Outcome category Cardiovascular mortality        Full outcome definition Deaths following myocardial infarction, cardiac arrhythmia, resuscitation, heart failure or stroke Prediction horizon In‐hospital or within 30 days
Analysis	Number of outcomes 543 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: patients were included from 15 years onwards meaning that the percentage with comorbidities is much lower compared to development study  Domain 2: Predictors High Justification: ICD codes were used as RCRI predictor definitions and high‐risk surgery was defined as retroperitoneal, intrathoracic or suprainguinal vascular procedures Domain 3: Outcome High Justification: outcome is cardiovascular death in this study and MACE in the development study Overall judgement High Justification: the inclusion criteria were broader compared to the development study. ICD codes were used as RCRI 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	No	ICD codes were used as RCRI predictor definitions.
Domain 3: Outcome	Yes	Clearly defined outcome definitions and appropriate adjudication of outcomes.
Domain 4:  Analysis	Yes	However, no confidence intervals or standard error for the c‐statistics.
Overall judgement	No	Appropriate selection of patients and clearly defined outcomes with proper methodology. However, ICD codes were used as RCRI predictor definitions.