Validation of a model to predict all-cause in-hospital mortality in vascular surgical patients.
OBJECTIVE
To develop and validate a pre- and postoperative model of all-cause in-hospital mortality in South African vascular surgical patients.


METHODS
We carried out a retrospective cohort study. A multivariate analysis using binary logistic regression was conducted on a derivation cohort using clinical, physiological and surgical data. Interaction and colinearity between covariates were investigated. The models were validated using the Homer-Lemeshow goodness-of-fit test.


RESULTS
Independent predictors of in-hospital mortality in the pre-operative model were: (1) age (per one-year increase) [odds ratio (OR) 1.03, 95% confidence interval (CI) 1.0-1.06), (2) creatinine > 180 micromol.l(-1) (OR 6.43, 95% CI: 3.482-11.86), (3) chronic beta-blocker therapy (OR 2.48, 95% CI: 1.38-4.48), and (4) absence of chronic statin therapy (OR 2.81, 95% CI: 1.15-6.83). Independent predictors of mortality in the postoperative model were: (1) age (per one-year increase) (OR 1.05, 95% CI: 1.02-1.09), (2) creatinine > 180 micromol.l(-1) (OR 5.08, 95% CI: 2.50-10.31), (3) surgery out of hours without statin therapy (OR 8.27, 95% CI: 3.36-20.38), (4) mean daily postoperative heart rate (HR) (OR 1.02, 95% CI: 1.0-1.04), (5) mean daily postoperative HR in the presence of a mean daily systolic blood pressure of less than 100 beats per minute or above 179 mmHg (OR 1.02, 95% CI: 1.01-1.03) and (6) mean daily postoperative HR associated with withdrawal of chronic beta-blockade (OR 1.02, 95% CI: 1.01-1.03). Both models were validated.


CONCLUSIONS
The pre-operative model may predict the risk of in-hospital mortality associated with vascular surgery. The postoperative model may identify patients whose risk increases as a result of surgical or physiological factors.
Biccard
B M
BM
Department of Anaesthetics, Nelson R Mandela School of Medicine and Inkosi Albert Luthuli Central Hospital, Durban, South Africa. biccardb@ukzan.ac.za
Pooran
R R
RR
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000367:Age Factors; D000368:Aged; D001794:Blood Pressure; D002318:Cardiovascular Diseases / Q000401:mortality* / Q000503:physiopathology / Q000601:surgery*; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood; D005260:Female; D006339:Heart Rate; D017052:Hospital Mortality; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D015233:Models, Statistical; D015999:Multivariate Analysis; D011184:Postoperative Period; D011237:Predictive Value of Tests; D011300:Preoperative Care; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013019:South Africa; D014656:Vascular Surgical Procedures / Q000401:mortality*
D000319:Adrenergic beta-Antagonists; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D003404:Creatinine