Correlation of Pre-Operative Co-Morbidity Indices with Peri-Operative and Post-Operative Metrics in Urological Patients Undergoing Major Open Procedures

Background:Individual surgeon and institutional performance are usually assessed by morbidity and mortality rates, which can be calculated using peri-operative metrics, such as POSSUM (Physiological and Operative Severity Score for the enUmeration of mortality and morbidity). Post-operative risk can be estimated using the surgical Apgar outcome score. However, pre-operative co-morbidity may contribute to case risk diversity and affect immediate peri-operative metrics and short- and long-term morbidity and mortality. We estimated the correlation between pre-operative co-morbidity or risk assessment indices and peri-operative metrics in urological patients. Material and Methods:The study included 100 consecutive patients (80.8% males, mean age ± SD 66.3 ± 10.7 years, range 30 - 88 years) undergoing major open urological procedures (39 nephrectomies, 43 radical prostatectomies, 18 radical cystectomies). Pre-operative co-morbidity was assessed using Charlson Comorbidity Index (CCI), age-adjusted CCI (AA-CCI), Cumulative Illness Rating Scale (CIRS), and Index of Co-Existent Diseases (ICED). Pre-operative risk was assessed with the American Society of Anesthesiologists index (ASA). Functional status was quantified based on estimation of the metabolic equivalent (MET). Peri-operative metrics included POSSUM and surgical Apgar scores. Results: All pre-operative indices significantly correlated with POSSUM, but none correlated with the surgical Apgar score. Conclusions:In patients undergoing major open urological procedures, risk stratification in the post-operative setting using the surgical Apgar score is independent of pre-operative co-morbidity status. In contrast, pre-operative co-morbidity and risk assessment correlated with peri-operative metrics used to calculate morbidity and mortality risk. Reports of death and complication rates do not take into account case diversity and, therefore, should be adjusted for co-morbidity status.