Peri-operative mortality depends on the patient's co-morbidities. ASA Physical Status (American Society of Anesthesiology) is the most commonly scale to assess this parameter and has yet been repeatedly criticized in the past for its discriminatory power.

Few studies have shown both the ASA physical status and the more detailed and more time-consuming Charlson Comorbidity Index to be equivalent in certain patient populations.

The purpose of this observational study is to compare the predictive value of both scales with regards to all-cause in-hospital mortality and hospital length of stay.

Inclusion Criteria:

1) All male and female Patients who underwent anesthesia within the study time period (January 2006 and December 2011) in the Charité - University Berlin, Department of Anesthesiology and Intensive Care Medicine CVK/CCM.

Exclusion Criteria:

None

All patients undergoing general anesthesia between January 2006 and December 2011