Addition of clinical risk scores improves prediction performance of American Society of Anesthesiologists (ASA) physical status classification for postoperative mortality in older patients: a pilot study.

Purpose: Many methods for preoperative risk stratifications used in everyday practice do not take into account all of the comorbidities and complex physiological status of older patients. Therefore, anaesthesiologists and surgeons must consider multiple ways of preoperative diagnostics. Determining which of the preoperative clinical risk scores [Revised Lee score, the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) calculator and Surgical Outcome Risk Tool (SORT)] best improves routinely used American Society of Anaesthesiologists (ASA) physical status classification.

Methods: The prospective pilot study included 78 patients who were being prepared for extensive non-cardiac surgeries under general anaesthesia. Preoperatively, anaesthesiologist determined ASA score according to guidelines. Then, the data of patients have been processed on the interactive calculators of Revised Lee score, ACS NSQIP and SORT.

Results: Mean age of included patients was 71.4 ± 6.9 years. When it comes to postoperative mortality prediction, three risk scores (ASA, ACS NSQIP and SORT) have been statistically significant, respectively, P = 0.016, P < 0.0001, P < 0.0001. Results showed that AUC being higher in ACS NSQIP and SORT (0.813; 0.797). Out of all three additional risk scores, ACS NSQIP showed to add the most to the specificity and sensitivity of ASA score, with combined AUC = 0.841.

Conclusions: ACS NSQIP and SORT increase the accuracy of ASA score. Revised Lee score cannot be considered a good indicator of postoperative mortality risk since it is primarily the score which indicates risk for cardiovascular complications. Further studies, with a greater number of patients, are needed.