POSSUM and P-POSSUM scoring systems overpredicted operative mortality in young patients and underpredicted it in the elderly (P<0.001) and in emergency colorectal cases (P<0.05).
Observational (n=1,017)
Yes
Do POSSUM and P-POSSUM scoring systems accurately predict operative mortality in patients undergoing major colorectal surgery?
POSSUM and P-POSSUM scoring systems lack calibration at extremes of age and high emergency workloads in colorectal surgery, requiring recalibration for accurate performance auditing.
p-value: p=<0.001
BACKGROUND: The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) and Portsmouth POSSUM (P-POSSUM) equations were derived from a heterogeneous general surgical population and have been used successfully as audit tools to provide risk-adjusted operative mortality rates. Their applicability to high-risk emergency colorectal operations has not been established. METHODS: POSSUM variables were recorded for 1017 patients undergoing major elective (n = 804) or emergency (n = 213) colorectal surgery in ten hospitals. Subgroup analysis was performed to investigate the predictive capability of POSSUM and P-POSSUM in emergency and elective surgery and in patients in different age groups. RESULTS: The overall operative mortality rate was 7.5 per cent (POSSUM-estimated mortality rate 8.2 per cent; P-POSSUM-estimated mortality rate 7.1 per cent). In-hospital deaths increased exponentially with age. Both scoring systems overpredicted mortality in young patients and underpredicted mortality in the elderly (P < 0.001). Death was underpredicted by both systems for emergency cases, significantly so at a simulated emergency caseload of 47.9 per cent (P < 0.05). CONCLUSION: There is a lack of calibration of POSSUM and P-POSSUM systems at the extremes of age and high emergency workload. This has important implication in clinical practice, as consultants with a high emergency workload may seem to underperform when these scoring systems are applied. Recalibration or remodelling strategies may facilitate the application of POSSUM-based systems in colorectal surgery.
Tekkis et al. (Fri,) conducted a observational in Colorectal surgery (n=1,017). POSSUM and P-POSSUM scoring systems vs. Observed mortality was evaluated on Operative mortality (p=<0.001). POSSUM and P-POSSUM scoring systems overpredicted operative mortality in young patients and underpredicted it in the elderly (P<0.001) and in emergency colorectal cases (P<0.05).