[Charlson index and the surgical risk scale in the analysis of surgical mortality]

There is controversy over how to assess surgical mortality risks after different operations. The purpose of this study was to assess the surgical factors that influenced surgical mortality and the ability of the Charlson Index and The Surgical Risk Scale (SRS) to determine low risk patients.

All patients who died during the period 2004-2007 were included. The score of both indices (Charlson and SRS) were recorded. A score of «0» for the Charlson Index and «8» for the SRS were chosen as the cut-off point between a low and high probability of death. Three risk groups were established: Low when the Charlson was =0 and SRS was <8; Intermediate when the Charlson was >0 and the SRS <8 or Charlson=0 and SRS ≥8; and high when the Charlson was>0 and the SRS ≥8. The risks factors before, during and after surgery were compared between the groups.

A total of 72,771 patients were surgically intervened, of which 7011 were urgent. One in every 1455 patients died during surgery and 1 in every 112 died during their hospital stay. Thirteen (2%) patients who died belonged to the low risk group, 199 (30.7%) to the intermediate risk group, and 434 (67.2%) to the high risk group. Heart disease was associated with the high risk group. The urgency of the operation was a determining factor associated with surgical complexity. Re-intervention and sepsis predominated as a cause of death in the low risk group, and in the rest of the groups a cardiac cause was the predominant factor.

The combination of the Charlson Index and SRS detected those patients with a low risk of death, thus making it a useful tool to audit surgical results.