A qualitative systematic review was conducted to assess the performance of tools which have been validated for the prediction of morbidity and/or mortality, in heterogeneous cohorts of surgical (non-cardiac, non-neurological) patients. The Portsmouth- Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) and the Surgical Risk Scale (SRS) were found to be the most widely validated and accurate risk stratification tools. The POSSUM, P-POSSUM and SRS were then validated in a population of patients who had major non-cardiac surgery in a metropolitan UK hospital. Their accuracy (discrimination) was compared against two novel predictors - the additive POSSUM score and the POSSUM physiology score. P-POSSUM and the additive POSSUM score predicted short-term mortality with high-moderate accuracy. The POSSUM Physiology score was moderately accurate and therefore worthy of further evaluation. Both POSSUM and P-POSSUM were poorly calibrated for this population. The relationships between perioperative risk, postoperative morbidity (measured using the Post Operative Morbidity Survey, POMS), postoperative length of hospital stay, and short-term mortality, were explored in a series of univariate analyses. There were differences in short-term mortality, and the patterns and prevalence of POMS-defined morbidity between surgical specialities. Cox Proportional Hazards Modelling, using time-dependent covariates, was undertaken to explore the independent relationship between perioperative risk, postoperative morbidity and long-term survival. POMS-defined neurological morbidity (prevalence 2.9%) was independently associated with reduced long-term survival. Prolonged postoperative morbidity, defined as the presence of POMS-defined morbidity on Day 15 post-surgery (prevalence 15.6%), conferred a relative hazard for death in the first 12 months post surgery of 3.52 (p<0.001; 95% C.I. 2.23-5.43) and for the next two years of 2.33 (p<0.001; 95% C.I. 1.56-3.50). Postoperative morbidity is a significant public health issue and poses a risk to longer-term survival; it would be an important measure of the quality of perioperative healthcare
