POSSUM and P-POSSUM overpredict mortality for carotid endarterectomy.
OBJECTIVE
the aim was to test the predictive accuracy of POSSUM and P-POSSUM on patients undergoing CEA.


METHODS
retrospective and prospective study.


METHODS
499 CEAs performed by four vascular surgeons from a single unit from 1992-99. The median age was 68 (range 38-86) and 60% were men.


METHODS
physiological parameters, operative parameters and the 30-day mortality were collected. Predicted mortality for each patient was calculated using POSSUM and P-POSSUM equations. Patients were stratified into risk groups and observed and predicted deaths were compared. Accuracy of the prediction was assessed using chi-squared analysis.


RESULTS
the observed 30-day mortality was 1.8% (9/499). The predicted deaths using POSSUM and P-POSSUM analysis were 49 and 25 respectively compared to nine observed deaths. There was significant evidence of lack of fit of both models in predicting mortality (chi-squared analysis, p<0.05).


CONCLUSIONS
POSSUM and P-POSSUM overpredict mortality and are unsuitable for comparative audit of CEA. Models developed specific for CEA might accurately predict mortality.
Kuhan
G
G
Academic Vascular Unit, Hull Royal Infirmary, Hull, UK.
Abidia
A F
AF
Wijesinghe
L D
LD
Chetter
I C
IC
Johnson
B F
BF
Wilkinson
A R
AR
Renwick
P M
PM
McCollum
P T
PT
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002340:Carotid Artery Diseases / Q000401:mortality* / Q000601:surgery*; D016894:Endarterectomy, Carotid / Q000401:mortality*; D005260:Female; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012189:Retrospective Studies