Estimation of mortality and morbidity risk in vascular surgery using POSSUM and the Portsmouth predictor equation

Risk Prediction Models for Peri-Operative Mortality in Patients Undergoing Major Vascular Surgery with Particular Focus on Ruptured Abdominal Aortic Aneurysms: A Scoping Review

PURPOSE

The present scoping review aims to describe and analyze available clinical data on the most commonly reported risk prediction indices in vascular surgery for perioperative mortality, with a particular focus on ruptured abdominal aortic aneurysm (rAAA).

MATERIALS AND METHODS

A scoping review following the PRISMA Protocols Extension for Scoping Reviews was performed. Available full-text studies published in English in PubMed, Cochrane and EMBASE databases (last queried, 30 March 2023) were systematically reviewed and analyzed. The Population, Intervention, Comparison, Outcome (PICO) framework used to construct the search strings was the following: in patients with aortic pathologies, in particular rAAA (population), undergoing open or endovascular surgery (intervention), what different risk prediction models exist (comparison), and how well do they predict post-operative mortality (outcomes)?

RESULTS

The literature search and screening of all relevant abstracts revealed a total of 56 studies in the final qualitative synthesis. The main findings of the scoping review, grouped by the risk score that was investigated in the original studies, were synthetized without performing any formal meta-analysis. A total of nine risk scores for major vascular surgery or elective AAA, and 10 scores focusing on rAAA, were identified. Whilst there were several validation studies suggesting that most risk scores performed adequately in the setting of rAAA, none reached 100% accuracy. The Glasgow aneurysm score, ERAS and Vancouver score risk scores were more frequently included in validation studies and were more often used in secondary studies. Unfortunately, the published literature presents a heterogenicity of results in the validation studies comparing the different risk scores. To date, no risk score has been endorsed by any of the vascular surgery societies.

CONCLUSIONS

The use of risk scores in any complex surgery can have multiple advantages, especially when dealing with emergent cases, since they can inform perioperative decision making, patient and family discussions, and post hoc case-mix adjustments. Although a variety of different rAAA risk prediction tools have been published to date, none are superior to others based on this review. The heterogeneity of the variables used in the different scores impairs comparative analysis which represents a major limitation to understanding which risk score may be the "best" in contemporary practice. Future developments in artificial intelligence may further assist surgical decision making in predicting post-operative adverse events.

Application of POSSUM and P-POSSUM scores in the risk assessment of elderly hip fracture surgery: systematic review and meta-analysis

Background

Since Mohamed et al. analyzed 2326 orthopedic cases in 2002 and believed that the POSSUM formula can be directly used to predict postoperative morbidity and mortality in orthopedic patients, applications of POSSUM and P-POSSUM scores in the hip fracture surgery have been mostly reported in the field of orthopedics, but there are still some inconsistencies in the related reports.

Methods

The electronic library was searched for all literature that met the purpose from its inception to 2021. Relative risk (RR) was selected to evaluate whether the model could be used to assess the risk of surgery in patients with elderly hip fractures. Finally, sensitivity analyses and subgroup analyses were performed.

Results

Thirteen studies were finally included, including 9 retrospective and 4 prospective studies.The morbidity analysis includes 11 studies, and the result was RR = 1.07 (95% CI 0.93–1.24), The mortality analysis includes 11 studies on POSSUM and 5 studies on P-POSSUM. The results of mortality by POSSUM and by P-POSSUM were RR = 1.93 (95% CI 1.21–3.08) and RR = 1.15 (95% CI 0.89–1.50), respectively. POSSUM had more accuracy to predict mortality for sample < 200 subgroup(RR = 2.45; 95% CI 0.71–8.42) than sample > 200 subgroup(RR = 1.59; 95% CI 1.06–2.40), and in the subgroup of hip fractures that did not distinguish between specific fracture types(RR = 1.69, 95% CI 0.87–3.32) than intertrochanteric neck fracture subgroup(RR = 5.04, 95% CI 1.07–23.75) and femoral femoral fracture subgroup(RR = 1.43,95% CI 1.10–1.84).

Conclusion

POSSUM can be used to predict morbidity in elderly hip fractures. The P-POSSUM was more accurate in predicting mortality in elderly hip fracture patients compared to the POSSUM, whose predictive value for mortality was influenced by the sample size and type of fracture studied. In addition, we believe that appropriate improvements to the POSSUM system are needed to address the characteristics of orthopedic surgery.

Prediction of Mortality in Patients After Oncologic Gastrointestinal Surgery: Comparison of the ASA, APACHE II, and POSSUM Scoring Systems

Scoring systems have been developed to predict the expected mortality and morbidity in surgical procedures. In this study, our aim was to compare the ASA (American Society of Anesthesiologists), APACHE (Acute Physiology and Chronic Health Evaluation) II, POSSUM (Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity) scoring systems as predictors of mortality in patients who underwent gastrointestinal oncologic surgery, followed, and were admitted to the intensive care unit during the postoperative period. We examined the files of 82 patients who underwent oncologic gastrointestinal surgery and followed up in the intensive care units (ICUs). The patients’ APACHE II scores and predicted mortality rates (PMR) according to the APACHE II, POSSUM, and ASA scores were ​​calculated. The receiver operator characteristic (ROC) curve analysis was used when evaluating the performances of the ASA, APACHE, and POSSUM scoring systems in terms of accurate assessment of mortality. Accordingly, the area under the curve (AUC) = 0.5 no distinction, 0.5 <AUC <0.7 discriminative power of the test is statistically not significant, 0.7 <AUC <0.8 acceptable, 0.8 <AUC <0.9 very good and 0.9 <AUC <1 perfect. The evaluations showed that APACHE II had the best performance with 0.81, followed by POSSUM, which had an acceptable level at 0.78. On the other hand, the ASA score was 0.63 and its discriminative power was identified as statistically insignificant. Our results show that the POSSUM and APACHE II scoring systems were better at predicting mortality than the ASA scoring system for the prediction of mortality in the postoperative period. Both the POSSUM and APACHE II scoring systems can be confidently used for the prediction of mortality in patients undergoing operations due to oncologic gastrointestinal diseases.

Challenges Encountered during the Treatment of Acute Mesenteric Ischemia

Results

Acute ischemia of the bowel mesentery was diagnosed in 41 patients (27 women and 14 men; mean age, 65.4 years). All patients underwent laparotomy. For 13 (31.71%) patients, surgery was performed within the first 24 hours of the clinical symptom onset. Mesenteric artery embolectomy without intestine resection was performed for 7 (17.07%) patients. Partial intestine resection due to necrosis was performed for 21 (51.22%) patients. Exploratory laparotomy without a therapeutic procedure was performed for 13 (31.71%) patients. Fifteen (36.59%) patients were discharged home in good general condition. Twenty-six (63.41%) patients died. The time from the clinical symptom onset until intervention exceeded 24 hours for all patients who died. Surgery within the first 24 hours reduced mortality associated with acute mesenteric ischemia (P = 0.001). Female sex, age older than 65 years, obesity (body mass index > 30), diabetes, chronic kidney disease, and smoking were adverse prognostic factors for increased mortality for patients with acute bowel ischemia.

Conclusion

The time from clinical symptoms to acute mesenteric ischemia treatment was the main prognostic factor and helped determine appropriate management. Early diagnosis and rapid intervention improved treatment outcomes and survival.

Quality of Life and Traditional Outcome Results at 1 Year in Elderly Patients Having Critical Limb Ischemia and the Role of Conservative Treatment

Introduction:

Revascularization is the cornerstone of the treatment of critical limb ischemia (CLI), but the number of elderly frail patients increase. Revascularization is not always possible in these patients and conservative therapy seems to be an option. The goals of this study are to analyze the 1-year quality of life (QoL) results and mortality rates of elderly patients with CLI and to investigate if conservative treatment could be an acceptable treatment option.

Methods:

Patients with CLI ≥70 years old were included in a prospective observational cohort study in 2 hospitals in the Netherlands between 2012 and 2016 and were divided over 3 treatment modalities: endovascular therapy, surgical revascularization, and conservative treatment. The World Health Organization Quality of Life (WHOQoL-Bref) instrument, a generic QoL assessment tool that includes components of physical, psychological, social relationships and environment, was used to evaluate QoL at baseline, 6 months, and 1 year.

Results:

In total, 195 patients (56% male, 33% Rutherford 4, mean age of 80) were included. Physical QoL significantly increased after surgical (10.4 vs 14.9, P < .001), endovascular (10.9 vs 13.7, P < .001), and conservative therapy (11.6 vs 13.2, P = .01) at 1 year. One-year mortality was relatively low after surgery (10%) compared to endovascular (40%) and conservative therapy (37%).

Conclusion:

The results of this study could not be used to designate the superior treatment used in elderly patients with CLI. Conservative treatment could be an acceptable treatment option in selected patients with CLI unfit for revascularization. Treatment of choice in elderly patients with CLI is based on multiple factors and should be individualized in a shared decision-making process.

Cost-effectiveness of the treatments for critical limb ischemia in the elderly population

OBJECTIVE

The treatment of critical limb ischemia (CLI), with the intention to prevent limb loss, is often an intensive and expensive therapy. The aim of this study was to examine the cost-effectiveness of endovascular and conservative treatment of elderly CLI patients unsuitable for surgery.

METHODS

In this prospective observational cohort study, data were gathered in two Dutch peripheral hospitals. CLI patients aged 70 years or older were included in the outpatient clinic. Exclusion criteria were malignant disease, lack of language skills, and cognitive impairment; 195 patients were included and 192 patients were excluded. After a multidisciplinary vascular conference, patients were divided into three treatment groups (endovascular revascularization, surgical revascularization, or conservative therapy). Subanalyses based on age were made (70-79 years and ≥80 years). The follow-up period was 2 years. Cost-effectiveness of endovascular and conservative treatment was quantified using incremental cost-effectiveness ratios (ICERs) in euros per quality-adjusted life-years (QALYs).

RESULTS

At baseline, patients allocated to surgical revascularization had better health states, but the health states of endovascular revascularization and conservative therapy patients were comparable. With an ICER of €38,247.41/QALY (∼$50,869/QALY), endovascular revascularization was cost-effective compared with conservative therapy. This is favorable compared with the Dutch applicable threshold of €80,000/QALY (∼$106,400/QALY). The subanalyses also established that endovascular revascularization is a cost-effective alternative for conservative treatment both in patients aged 70 to 79 years (ICER €29,898.36/QALY; ∼$39,765/QALY) and in octogenarians (ICER €56,810.14/QALY; ∼$75,557/QALY).

CONCLUSIONS

Our study has shown that endovascular revascularization is cost-effective compared with conservative treatment of CLI patients older than 70 years and also in octogenarians. Given the small absolute differences in costs and effects, physicians should also consider individual circumstances that can alter the outcome of the intervention. Cost-effectiveness remains one of the aspects to take into consideration in making a clinical decision.

Risk-Adjusted Analysis of Patients Undergoing Emergency Laparotomy Using POSSUM and P-POSSUM Score: A Prospective Study

Background:

Comparison of operative morbidity rates after emergency laparotomy between units may be misleading because it does not take into account the physiological variables of patients’ conditions. Surgical risk scores have been created, and the most commonly used is the Physiological and Operative Severity Score for the enumeration of Mortality (POSSUM) or one of its modifications, the Portsmouth-POSSUM (P-POSSUM), usually requires intraoperative information.

Objective:

The objective of this study is to evaluate the POSSUM and P-POSSUM scores in predicting postoperative morbidity and mortality in patients undergoing emergency laparotomy.

Methodology:

This is a prospective, cross-sectional, and hospital-based study that was conducted at J.L.N. Medical College and Hospital, Ajmer, Rajasthan, India, from April 2017 to December 2017. Adult patients who presented at the causality and underwent emergency laparotomy were included in the study. Observed and predicted mortality and morbidity were calculated using POSSUM and P-POSSUM equations, and statistical significance was calculated using Chi-square test.

Results:

A total of 100 patients were included in this study, with a mean age of 42.83 ± 18.21 years. The observed (O) mortality was 12 (12.0%), while POSSUM predicted 40 (40%) and P-POSSUM 27 (27%). The O/E ratio for POSSUM was 0.29 and for P-POSSUM was 0.44, and this means that they both overestimate mortality. When the results were tested by Chi-square test, the P value was found to be 0.55 and 0.85 for POSSUM and P-POSSUM, respectively, which showed no significant correlation for observed and expected mortality. The observed morbidity was 69 (69%), while POSSUM expected morbidity was 79 (79%), O/E ratio is 0.87, and this again overestimates the morbidity. POSSUM is overpredicting the rate of morbidity, and test of correlation showed no significance with P = 0.75.

Conclusion:

POSSUM and P-POSSUM were found to overestimate mortality and morbidity in our patient's population.

Feasibility of a Modified E-PASS and POSSUM System for Postoperative Risk Assessment in Patients with Spinal Disease

OBJECTIVE

This retrospective case control study aimed to evaluate the feasibility of using Estimation of Physiological Ability and Surgical Stress (E-PASS) and Physiological and Operative Severity Score for the enumeration of Mortality and Morbidity (POSSUM) systems in patients undergoing spinal surgical procedures. Degenerative spine disease has increased in incidence in aging societies, as has the number of older adult patients undergoing spinal surgery. Many older adults are at a high surgical risk because of comorbidity and poor general health.

METHODS

We retrospectively reviewed 217 patients who had undergone spinal surgery at a single tertiary care. We investigated complications within 1 month after surgery. Criteria for both skin incision in E-PASS and operation magnitude in the POSSUM system were modified to fit spine surgery. We calculated the E-PASS and POSSUM scores for enrolled patients, and investigated the relationship between postoperative complications and both surgical risk scoring systems. To reinforce the predictive ability of the E-PASS system, we adjusted equations and developed modified E-PASS systems.

RESULTS

The overall complication rate for spinal surgery was 22.6%. Forty-nine patients experienced 58 postoperative complications. Nineteen major complications, including hematoma, deep infection, pleural effusion, progression of weakness, pulmonary edema, esophageal injury, myocardial infarction, pneumonia, reoperation, renal failure, sepsis, and death, occurred in 17 patients. The area under the receiver operating characteristic curve (AUC) for predicted postoperative complications after spine surgery was 0.588 for E-PASS and 0.721 for POSSUM. For predicted major postoperative complications, the AUC increased to 0.619 for E-PASS and 0.842 for POSSUM. The AUC of the E-PASS system increased from 0.588 to 0.694 with the Modified E-PASS equation.

CONCLUSIONS

The POSSUM system may be more useful than the E-PASS system for estimating postoperative surgical risk in patients undergoing spine surgery. The preoperative risk scores of E-PASS and POSSUM can be useful for predicting postoperative major complications. To enhance the predictability of the scoring systems, using of modified equations based on spine surgery-specific factors may help ensure surgical outcomes and patient safety.

Beta Blockade and Clinical Outcomes in Aneurysmal Subarachnoid Hemorrhage

Background:

Aneurysmal subarachnoid hemorrhages are frequently complicated by hypertension and neurogenic myocardial stunning. Beta blockers may be used for management of these complications. We sought to investigate sympathetic nervous system modulation by beta blockers and their effect on radiographic vasospasm, delayed cerebral infarction, discharge destination and death.

Methods:

Retrospective chart review of 218 adults admitted to the ICU between 8/2004 and 9/2010 was performed. Groups were identified relevant to beta blockade: 77 were never beta blocked (No/No), 123 received post-admission beta blockers (No/Yes), and 18 were continued on their home beta blockers (Yes/Yes). Records were analyzed for baseline characteristics and the development of vasospasm, delayed cerebral infarction, discharge destination and death, expressed as adjusted odds ratio.

Results:

Of the 218 patients 145 patients developed vasospasm, 47 consequently infarcted, and 53 died or required care in a long-term facility. When compared to No/No patients, No/Yes patients had significantly increased vasospasm (OR 2.11 (1.06-4.16)). However, these patients also had significantly fewer deaths or need for long term care (OR 0.17 (0.05-0.64)), with decreased tendency for infarcts (OR 0.70 (0.32-1.55)). When compared to No/No patients, Yes/Yes patients demonstrated a trend toward increased vasospasm (OR 1.61 (0.50-5.29)) that led to infarction (OR 1.51 (0.44-5.13)), but with decreased mortality or need for long term care in a facility (OR 0.13 (0.01-1.30)).

Conclusion:

Post-admission beta blockade in aneurysmal subarachnoid hemorrhage patients was associated with increased incidence of vasospasm. However, despite the increased occurrence of vasospasm, beta blockers were associated with improved discharge characteristics and fewer deaths.

Evaluation of illness severity scoring systems and risk prediction in vascular intensive care admissions

INTRODUCTION

This study examines the predictive value of intensive care unit (ICU) scoring systems in a vascular ICU population.

METHODS

From April 2005 to September 2011, we examined 363 consecutive ICU admissions. Simplified Acute Physiology Score II (SAPS II), Acute Physiology and Chronic Health Evaluation II (APACHE II), APACHE IV, Multiple Organ Dysfunction Score (MODS), organ dysfunctions and/or infection (ODIN), mortality prediction model (MPM) and physiologic and operative severity score for the enumeration of mortality and morbidity (POSSUM) were calculated. The Glasgow Aneurysm Score (GAS) was calculated for patients with aneurysm-related admissions.

RESULTS

Overall mortality for complex vascular intervention was 11.6%. At admission, the areas under the receiver operating characteristic curve (AUCs) was 0.884 for SAPS II, 0.894 for APACHE II, 0.895 for APACHE IV, 0.902 for MODS, 0.891 for ODIN and 0.903 for MPM. At 24 h, model discrimination was best for POSSUM (AUC = 0.906) and MPM (AUC = 0.912).

CONCLUSION

The good discrimination of these scoring systems indicates their value as an adjunct to clinical assessment but should not be used on an individual basis as a clinical decision-making tool.

Predicting postoperative complications of head and neck squamous cell carcinoma in elderly patients using random forest algorithm model

BACKGROUND

Head and Neck Squamous Cell Carcinoma (HNSCC) has a high incidence in elderly patients. The postoperative complications present great challenges within treatment and they're hard for early warning.

METHODS

Data from 525 patients diagnosed with HNSCC including a training set (n = 513) and an external testing set (n = 12) in our institution between 2006 and 2011 was collected. Variables involved are general demographic characteristics, complications, disease and treatment given. Five data mining algorithms were firstly exploited to construct predictive models in the training set. Subsequently, cross-validation was used to compare the different performance of these models and the best data mining algorithm model was then selected to perform the prediction in an external testing set.

RESULTS

Data from 513 patients (age > 60 y) with HNSCC in a training set was included while 44 variables were selected (P < 0.05). Five predictive models were constructed; the model with 44 variables based on the Random Forest algorithm demonstrated the best accuracy (89.084%) and the best AUC value (0.949). In an external testing set, the accuracy (83.333%) and the AUC value (0.781) were obtained by using the random forest algorithm model.

CONCLUSIONS

Data mining should be a promising approach used for elderly patients with HNSCC to predict the probability of postoperative complications. Our results highlighted the potential of computational prediction of postoperative complications in elderly patients with HNSCC by using the random forest algorithm model.

POSSUM: A Scoring System for Perforative Peritonitis

BACKGROUND AND OBJECTIVES

Perforative peritonitis carries considerable morbidity and mortality with the postoperative period unpredictable most of the times. It therefore becomes necessary for a scoring system that predicts the post-operative outcome. POSSUM (Physiological and Operative Severity Score for the enumeration of Mortality and Morbidity) helps in predicting the post-operative morbidity and mortality in these patients. POSSUM scores are based on 12 physiological factors and 6 operative factors. In our study, we included two more factors, which are specifically important in perforative peritonitis; they are, perforation to operation time and the presence of co-morbidity. The presence of these factors significantly affects the post-operative status. Through this prospective study, we can predict which patients are at a higher risk of death or complication and give appropriate management as necessary.

MATERIALS AND METHODS

Our sample size was 50 patients with perforative peritonitis. The study was conducted in single unit from September 2013 to August 2014. Data was collected based on POSSUM scoring system. Outcome of the patients was recorded as death / alive; complicated / uncomplicated and statistical analysis was done by comparing the expected and observed outcomes.

RESULTS

By applying linear analysis, an observed to expected ratio of 1.005 was obtained for mortality and 1.001 for morbidity. There was no statistically significant difference between the observed and expected mortality rates (χ(2) = 3.54, p = 0.316) and morbidity rates (χ(2) = 2.40, p = 0.792). It was found to be comparable with other studies. The factors independently studied; perforation to operation time and presence of co-morbidity were statistically significant with respect to outcome (p<0.05).

CONCLUSION

Although a small sample size is the limitation of this study, POSSUM scoring system is a good indicator of postoperative outcome in patients with perforative peritonitis and was applicable in our setup. It is useful in identifying high risk patients and give preferential care to them for better outcome. Inclusion of factors like perforation to operation time and co-morbid status can improve the scoring system and better care can be provided.

Where are we in perioperative medicine for older surgical patients? A UK survey of geriatric medicine delivered services in surgery

INTRODUCTION

national reports have highlighted deficiencies in care provided to older surgical patients and suggested a role for innovative, collaborative, inter-specialty models of care. The extent of geriatrician-led perioperative services in the UK (excluding orthogeriatric services) has not previously been described. This survey describes current services and explores barriers to further development.

METHODS

an electronic survey was sent to clinical leads for geriatric medicine at all 161 acute NHS health care trusts in the UK. Reminders were sent on three occasions over an 8-week period. The survey examined preoperative and postoperative care and organisational issues. Responses were analysed descriptively.

RESULTS

there were 130 respondents (80.7%). One-third (38) of respondents described providing some geriatric medicine input in older surgical patients. Preoperative services existed in 15 (12%), where 14 provided risk assessment and 13 preoperative optimisation. Twenty-six respondents (20%) delivered care postoperatively, of them 10 took a reactive approach, 11 a proactive approach and 5 provided a combination of reactive and proactive care. Barriers to establishing perioperative geriatric medicine services included funding, workforce issues and a lack of inter-specialty collaboration.

CONCLUSION

a national appetite exists to provide geriatrician-led services to older surgical patients yet the majority of existing services remain reactive and do not use comprehensive geriatric assessment as an organising principle. This survey suggests that funding for geriatricians in perioperative care has not yet been universally established. Future efforts should focus on dissemination of experiential knowledge and published resources, collaboration with commissioners and empirical research to overcome the barriers described.

POSSUM and p-POSSUM overestimate morbidity and mortality in laparoscopic bariatric surgery

BACKGROUND

Despite their wide use in surgical audit, the application of the Physiologic and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM) and the Portsmouth predictor of mortality (p-POSSUM) in bariatric surgery has been limited. The aim of this study was to evaluate the usefulness of POSSUM and p-POSSUM in bariatric comparative audit.

METHODS

Data were retrospectively collected on consecutive patients who underwent laparoscopic gastric by-pass (LRYGB) and sleeve gastrectomy (SG) at a teaching institute. POSSUM and p-POSSUM equations were applied. The observed to expected ratios for morbidity and mortality were calculated. A Student's t test was performed to assess if a relationship could be found between the observed and the predicted outcomes.

RESULTS

Between 2008 and 2013, 504 patients (370 female) with a mean (range) age of 46 (17-69) years underwent LRYGB (n = 383) and SG (n = 121). The operative morbidity was 10.9% and mortality was .2%. POSSUM overpredicted morbidity (30.56%), and no relationship between morbidity risk and the development of complications was found (P = .152). There was a grouping of patients in the low-risk mortality groups for both POSSUM and p-POSSUM. Both equations overpredicted mortality (5.95% and 1.62%, respectively).

CONCLUSION

Both POSSUM and p-POSSUM equations overpredicted morbidity and mortality in this only study in the literature of modern bariatric practice that employed a large representative patient sample receiving the commonest procedures. A multicenter study is needed to address the low incidence of events and enable modification of those equations for use in bariatric surgical audit.

Using the E-PASS scoring system to estimate the risk of emergency abdominal surgery in patients with acute gastrointestinal disease

PURPOSE

The Estimation of Physiologic Ability and Surgical Stress (E-PASS) scoring system, which quantifies a patient's reserve and surgical stress, is used to predict morbidity and mortality in patients before elective gastrointestinal surgery. We conducted this study to clarify whether the E-PASS scoring system is useful for assessing the risks of emergency abdominal surgery.

METHODS

The subjects of this retrospective study were 51 patients who underwent emergency gastrointestinal surgery at a public general hospital. The main outcomes were the E-PASS scores and the postoperative course, defined by mortality and morbidity.

RESULTS

Postoperative complications developed in 15 of the 51 patients (29.4%). The E-PASS score was significantly higher in the patients with postoperative complications than in those without (0.61 ± 0.31 vs 0.20 ± 0.35, respectively; n = 36). The morbidity rates were significantly lower in the patients with a value less than 0.5 than in those with a value more than 0.5 (17.1% and 56.3%, respectively; P < 0.01). There were 7 operative deaths among the 16 patients with a high score, versus none among the 9 patients with a low score (P < 0.01). Three patients underwent laparoscopic-assisted bowel resection with a good postoperative course, with scores of less than 0.5.

CONCLUSIONS

The E-PASS scoring system is useful for surgical decision making and evaluating whether patients will tolerate emergency gastrointestinal surgery. Minimally invasive therapy would assist in lowering the risk of complications.

Establishing quality in colorectal surgery

AIM

The review aimed to offer a contemporary perspective of the quality of current colorectal surgery.

METHOD

A literature search was undertaken to identify relevant indicators. Citations were included if they related to quality in colorectal surgery. The search terms used included the Medical Subject Heading terms and Boolean characters: 'colon' OR 'colorectal', OR 'rectal' OR 'rectum' AND 'Quality Indicators', OR 'Quality Assurance', OR 'Quality of healthcare', OR 'Reference Standards', OR 'Quality' plus a variable floating term. A two-person independent review was undertaken from resulting citations and their consequent reference lists. The search was limited to citations from 2000 to 2010 in humans and to the English language.

RESULTS

Metrics identified as potential quality indicators in colorectal surgery are discussed according to the structure, process and outcome framework.

CONCLUSION

A clear appreciation of the scope of individual metrics for quality appraisal purposes is necessary if they are to be used meaningfully for performance benchmarking.

Pre-operative evaluation using therapeutic intensity scoring

BACKGROUND AND OBJECTIVE

A Pre-operative Therapeutic Intensity Score (P-TIS) was developed to quantify intensity of pre-operative care. Its association with post-operative ICU admission was explored.

METHODS

P-TIS assigns 1-4 points to therapeutic interventions and diagnostic procedures based on care intensity. P-TIS was evaluated using elective (n = 716) and emergency (n = 289) surgery patients entering the post-anaesthesia care unit (PACU) or directly admitted to ICU.

RESULTS

P-TIS has chronic (interventions >48 h before surgery, e.g. chronic dialysis therapy: 3 points, oral antibiotics: 1 point) and acute (interventions within 48 h of surgery, e.g. intra-aortic balloon: 4 points, urinary catheter insertion: 1 point) components. Acute P-TIS provided quantitative information, not provided by other methods, about care intensity immediately before surgery. High acute P-TIS were observed in elective patients with high chronic P-TIS and ASA classifications (3 and 4) and emergency surgery and trauma. The higher acute P-TIS, the more likely emergency patients are to receive post-operative ICU rather than intermediate or routine floor care (odds ratio 1.18, P < 0.001). Adding surgical complexity improved acute P-TIS's ability to predict post-operative ICU care in elective patients.

CONCLUSION

P-TIS quantifies the intensity of chronic and acute pre-operative care. Acute P-TIS predicted receipt of post-operative ICU care, especially in emergency surgery.

Usefulness of POSSUM physiological score for the estimation of morbidity and mortality risk after elective abdominal aortic aneurysm repair in Japan

BACKGROUND

The Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (POSSUM), which consists of a physiological score (PS) and an operative severity score, is useful in determining the risk profile for patients with abdominal aortic aneurysms in Western countries, but no information is available on the use of this method in Japan.

METHODS AND RESULTS

A retrospective cohort study involving 225 patients was performed, and the prognostic factors for morbidity and in-hospital mortality including POSSUM were investigated. The morbidity rate was 26%. On univariate analysis age, renal disease, hemoglobin, albumin, operation time, blood loss and PS were significantly different. On multivariate analysis PS was significantly different. Using receiver operating characteristic (ROC) analysis, PS had an area under the curve (AUC) of 0.712 and the best cut-off point was 18. The in-hospital mortality rate was 2.2%. On univariate analysis renal disease, albumin and PS were significantly different, and on multivariate analysis PS was significantly different. On ROC analysis PS had an AUC of 0.921 and the best cut-off point was 22.

CONCLUSIONS

PS was the only independent risk factor for morbidity and in-hospital mortality. Further studies may be required to develop a risk-scoring system.

A Preliminary Audit Experience of Surgery for Rectal Cancer after Neoadjuvant Chemoradiation Therapy

Aims and background

A surgical audit is a systematic critical analysis of surgical performance, with the goal to improve the quality of patient care. Rectal cancer surgery is one of the most delicate procedures in the field of surgical oncology, with significant variations in terms of complications from center to center. Neoadjuvant chemoradiation therapy leads to a significant reduction in local recurrences in patients with locally advanced lower and medium rectal cancer. The aim of the study was to evaluate the influence of neoadjuvant chemoradiation therapy on postoperative morbidity and mortality in patients with rectal cancer.

Methods and study design

From January 1,2003, to December 31, 2007, patients who underwent elective surgical resection for lower and medium rectal cancer in our Surgical Unit were prospectively analyzed. Patients (n = 42) were divided into two groups: 1) those treated with neoadjuvant chemotherapy and consequent surgical resection (19/42); 2) those treated with primary surgical treatment (23/42). P-POSSUM (Portsmouth Physiologic and Operative Severity Score for the Enumeration of Mortality and Morbidity) and CR-POSSUM (ColoRectal-POSSUM) scores were calculated for each patient group. Thirty-day mortality and morbidity rates were prospectively collected in a comprehensive data base. Data were evaluated by comparing the predictions of the two scoring systems in both study groups with clinically observed mortality and morbidity rates.

Results

In group 1, no death was registered (0/19). The P-POSSUM and CR-POSSUM expected mortality was 2.43% and 4.52%, respectively (P >0.05). In group 2, a single death was documented (1/23, 4.35%). The P-POSSUM and CR-POSSUM expected mortality was 2.1% and 4.94%, respectively. The postoperative complications rate for group 1 was 10.52% (2/19) compared to 34.88% as expected from the P-POSSUM score (P <0.05). In group 2, a postoperative complication rate of 39.13% (9/23) was observed compared to 34.26% as expected from the P-POSSUM score (P >0.05).

Conclusions

No significant influence on morbidity or mortality was detected in patients who underwent neoadjuvant radio-chemotherapy.

Evaluation of POSSUM for patients undergoing pancreatoduodenectomy

Background

Comparison of operative morbidity rates after pancreatoduodenectomy between units may be misleading because it does not take into account the physiological variable of the condition of the patients. The aim of the present study was to evaluate the Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM) for pancreatoduodenectomy patients and to look for risk factors associated with morbidity in a high-volume center.

Methods

Between January 1993 and April 2006, 652 patients underwent a pancreatoduodenectomy, 502 of them for malignant disease. POSSUM performance was evaluated by assessing the “goodness-of-fit” with the linear analysis method.

Results

Overall, 332 of the 652 patients (50.9%) had one or more complication after pancreatoduodenectomy, and 9 patients (1.4%) died. POSSUM had a significant lack of fit using goodness-of-fit analysis. In multivariate analysis, one statistically significant factor associated with morbidity and not incorporated in POSSUM (P < 0.05) was identified: ampulla of Vater adenocarcinoma (OR = 1.73, 95% CI: 1.07–2.80).

Conclusions

Overall, there is a lack of calibration of POSSUM among patients who undergo pancreatoduodenectomy.

Initial experience of laparostomy with immediate vacuum therapy in patients with severe peritonitis

INTRODUCTION

To report our initial experience of laparostomy and immediate intra-abdominal vacuum therapy in patients with severe peritonitis due to intra-abdominal catastrophes.

PATIENTS AND METHODS

Twenty-seven patients underwent emergency laparotomy and laparostomy formation with the application of immediate intra-abdominal TRAC-VAC therapy (male:female ratio, 1:1.2; median age, 73 years; range, 34-84 years). Predicted mortality was assessed using the P-POSSUM score and compared with clinically observed outcomes.

RESULTS

Ten patients (37%) with a mean predicted P-POSSUM mortality of 72%, died of sepsis and multi-organ failure. Seventeen patients (mean P-POSSUM 48% expected mortality) survived to discharge. One patient with pancreatitis died from small bowel obstruction 1-year post discharge, two patients developed a small bowel fistula. One patient had an allergic reaction to the VAC dressing. Our patients, treated with laparostomy and TRAC VAC therapy, had a significantly improved observed survival when compared to P-POSSUM expected survival (P = 0.004).

CONCLUSIONS

Laparostomy with immediate intraperitoneal VAC therapy is a robust and effective system to manage patients with intra-abdominal catastrophes. There were significantly improved outcomes compared to the mortality predicted by P-POSSUM scores. Damage control surgery with laparostomy formation and intra-abdominal VAC therapy should be considered in patients with severe peritonitis.

Can elderly patients with colorectal cancer tolerate planned surgical treatment? A practical approach to a common dilemma

AIM

Analysing the effectiveness of a surgical procedure is mandatory in every modern health-care system. The aging of the population stresses the need for a good standard of care. This study tests the hypothesis that porthsmouth-physiologic operative severity score for enumeration of morbidity and mortality (P-POSSUM) and colorectal-POSSUM (CR-POSSUM) would be useful clinical auditing tools in colorectal cancer surgery for aged patients.

METHOD

One hundred and seventy-seven consecutive patients over 70 years of age underwent emergency or elective surgery from January 2003 to December 2005. Demographic, clinical and surgical information, score systems' prediction, complications and 30-day mortality data were prospectively entered in a comprehensive database. The observed over expected morbidity and mortality rate was calculated.

RESULTS

Thirty-day observed mortality was 10.3% (19/177) while P-POSSUM and CR-POSSUM expected mortality were, respectively, 11.21% (P = NS) and 13.08% (P = NS). Overall observed morbidity was 42.7%, P-POSSUM prediction was 59.3% (P = 0.002). Morbidity and mortality data were analysed for specific subgroups of patients (resection and anastomosis/resection and stoma/palliative; emergency/elective).

CONCLUSION

P-POSSUM and CR-POSSUM are useful tools to predict mortality in elderly patients. P-POSSUM significantly overestimated the risk of complications. A more accurate tool for preoperative assessment for aged patients is probably needed to predict the post-surgical outcome.

Evaluation of surgical performance using V-POSSUM risk-adjusted mortality rates

Vascular-Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (V-POSSUM) is a risk-adjusted scoring system for predicting 30-day mortality in patients undergoing vascular surgery. It can assess surgical performance by comparing predicted deaths with observed deaths. The aim of this analysis was to assess trends in surgical performance over time using risk-adjusted 30-day mortality as the primary outcome. Major vascular surgery procedures (n = 454) were prospectively scored for V-POSSUM between 1995 and 2006. Procedures were divided into 11 consecutive time bands. Observed and predicted deaths were compared using the logistic regression equation derived for V-POSSUM. The observed death rates decreased over time, as did the predicted number of deaths calculated from the V-POSSUM scores. The overall predicted mortality rate was 17.2% and the rate varied with the 12-month period, with a high of 23.9% and a low of 9.2%. The downward trend in the predicted rate shows that the patient risk factors have changed over time and that the risk of dying has declined by almost 50% (from 21.6 to 11.1%). There was a trend towards improved surgical performance over time, with a drop in the observed to predicted ratios of deaths. Observed and predicted deaths changed over the study periods. There was a trend towards improved performance compared with the risk-adjusted predicted mortality. V-POSSUM is a useful tool in the longitudinal assessment of performance in major vascular surgery.

Can SAPS II predict operative mortality more accurately than POSSUM and P-POSSUM in patients with colorectal carcinoma undergoing resection?

BACKGROUND

This study assessed the APACHE II (Acute Physiology and Chronic Health Evaluation II), SAPS II (Simplified Acute Physiology Score-II), POSSUM (Physiologic and Operative Severity Score for Enumeration of Morbidity and Mortality), and P-POSSUM (Portsmouth-POSSUM) in patients with colorectal cancer undergoing curative or palliative resection.

METHODS

Predicted mortality rates and the observed/expected mortality ratio were computed by means of each scoring system. The results were compared between survivors and nonsurvivors and between elective and emergency operations. Each model was assessed for its accuracy to predict the risk of death using receiver operator characteristic (ROC) curve analysis, and risk stratification was generated as well.

RESULTS

Some 224 patients were enrolled in the study. The overall 30-day mortality rate was 3.6% (n = 8). Predicted mortality rates generated by APACHE II, SAPS II, POSSUM, and P-POSSUM were 9.1%, 3.7%, 13.4%, and 5.2%, respectively. All the scoring systems assigned higher scores to those patients who died than to those who survived. Areas under the curve calculated by ROC curve analysis for APACHE II, SAPS II, POSSUM, and P-POSSUM were 0.786, 0.854, 0.793, and 0.831, respectively. Best stratification was achieved by the SAPS II score.

CONCLUSIONS

SAPS II and P-POSSUM were determined to be better predictors for patients with colorectal cancer undergoing resection. SAPS II also was found to have a higher degree of discriminatory power in colorectal resection for carcinoma. The predictive value of this useful severity score in several surgical subgroups must be examined to evaluate its routine use in risk-adjusted audit.

Application of Portsmouth modification of physiological and operative severity scoring system for enumeration of morbidity and mortality (P-POSSUM) in pancreatic surgery

BACKGROUND

Pancreatoduodenectomy (PD) is associated with high incidence of morbidity and mortality. We have applied P-POSSUM in predicting the incidence of outcome after PD to identify those who are at the highest risk of developing complications.

METHOD

A prospective database of 241 consecutive patients who had PD from January 2002 to September 2005 was retrospectively updated and analysed. P-POSSUM score was calculated for each patient and correlated with observed morbidity and mortality.

RESULTS

30 days mortality was 7.8% and morbidity was 44.8%. Mean physiological score was 16.07 +/- 3.30. Mean operative score was 13.67 +/- 3.42. Mean operative score rose to 20.28 +/- 2.52 for the complex major operation (p < 0.001) with 2 fold increase in morbidity and 3.5 fold increase in mortality. For groups of patients with a physiological score of (less than or equal to) 18, the O:P (observed to Predicted) morbidity ratio was 1.3-1.4 and, with a physiological score of >18, the O:P ratio was nearer to 1. Physiological score and white cell count were significant in a multivariate model.

CONCLUSION

P-POSSUM underestimated the mortality rate. While P-POSSUM analysis gave a truer prediction of morbidity, underestimation of morbidity and potential for systematic inaccuracy in prediction of complications at lower risk levels is a significant issue for pancreatic surgery.

POSSUM models in open abdominal aortic aneurysm surgery

OBJECTIVES

This study evaluated the Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM), Portsmouth (P) POSSUM and Vascular (V) POSSUM. The primary aim was to assess the validity of these scoring systems in a population of patients undergoing elective and emergency open AAA repair. The secondary intention was in the event that these equations did not fit all patients with an aneurysm; a new model would be developed and tested using logistic regression from the local data (Cambridge POSSUM).

METHODS

POSSUM data items were collected prospectively in a group of 452 patients undergoing elective and emergency open AAA repair over an eight-year period. The operative mortality rates were compared with those predicted by POSSUM, P-POSSUM, V-POSSUM and Cambridge POSSUM.

RESULTS

All models except V-POSSUM (physiology only) showed significant lack of fit when predicting mortality after open AAA surgery. It was found that the locally generated single unified model (Cambridge POSSUM) could successfully describe both elective and ruptured AAA mortality with good discrimination (chi(2)=9.24, 7 d.f., p=0.236, c-index=0.880).

CONCLUSIONS

POSSUM, V-POSSUM and P-POSSUM may not be robust tools for comparing mortality between populations undergoing elective and emergency open AAA repair as once thought. The development and successful validation of Cambridge POSSUM provides a unified model to describe both elective and emergency AAAs together and should be validated in other geographical settings.

Evaluation of various POSSUM models for predicting mortality in patients undergoing elective oesophagectomy for carcinoma

Background

The aim of the study was to validate the use of the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM), Portsmouth (P) POSSUM and upper gastrointestinal (O) POSSUM models in patients undergoing elective thoracic oesophagectomy for carcinoma.

Methods

The observed in-hospital mortality rates in 545 patients undergoing elective thoracic oesophagectomy for squamous cell carcinoma of the oesophagus in all public hospitals in Hong Kong was compared with rates predicted by POSSUM, P-POSSUM and O-POSSUM. The discriminatory power of these models was assessed using receiver–operator characteristic (ROC) curve analysis.

Results

The observed mortality rate was 5·5 per cent, whereas rates predicted by POSSUM, P-POSSUM and O-POSSUM were 15·0, 4·7 and 10·9 per cent respectively. P-POSSUM showed no lack of fit (P = 0·814), but POSSUM (P &lt; 0·001) and O-POSSUM (P = 0·002) showed lack of fit against observed mortality. POSSUM overpredicted mortality across nearly all risk groups, whereas O-POSSUM overpredicted mortality in patients with low physiological scores and in older patients. POSSUM (area under ROC curve 0·776) and P-POSSUM (0·776) showed equally good discriminatory power but O-POSSUM (0·676) was inferior.

Conclusion

P-POSSUM provided the most accurate prediction of in-hospital mortality in this group of patients who had elective oesophagectomy.

A newly devised scoring system for prediction of mortality in patients with colorectal cancer: a prospective study

BACKGROUND

Postoperative morbidity and mortality from colorectal cancer varies widely across hospitals in the UK. We aimed to assess whether a newly developed score from the Association of Coloproctology of Great Britain and Ireland (ACPGBI) could predict mortality from colorectal cancer surgery as accurately as the Physiology and Operative Severity Score for enUmeration of Mortality and morbidity (POSSUM), Portsmouth POSSUM (P-POSSUM), or the ColoRectal POSSUM (CR-POSSUM).

METHODS

We analysed prospectively 618 patients with histologically confirmed colorectal cancer who had surgery to remove primary tumours done by colorectal surgeons or non-colorectal surgeons in a 3-year period. We compared observed mortality with those predicted by the ACPGBI, POSSUM, P-POSSUM, and CR-POSSUM scoring systems using the Hosmer-Lemeshow test and Receiver Operating Characteristic (ROC) curve analysis.

FINDINGS

Between April 1, 2002, and May 31, 2005, 618 consecutive patients with colorectal cancer had surgery to remove primary tumours. Overall observed 30-day mortality over the 3 years was 10.2% (95% CI 8.0-12.9). Overall predicted mortality (mean score) by use of POSSUM was 12.7% (11.7-13.7), by use of P-POSSUM was 4.4% (3.4-5.4), by use of CR-POSSUM was 9.6% (8.6-10.6), and by use of ACPGBI score was 8.1% (7.3-8.8).

INTERPRETATION

POSSUM overpredicted mortality, whereas P-POSSUM underpredicted mortality from colorectal-cancer surgery. CR-POSSUM was a more-accurate predictor of mortality in most analyses than was POSSUM and P-POSSUM. Although CR-POSSUM gave the closest prediction of overall mortality, analyses of subgroups of patients showed that ACPGBI score predicted overall mortality most accurately.

SCORING SYSTEMS DO NOT ACCURATELY PREDICT OUTCOME FOLLOWING ABDOMINAL AORTIC ANEURYSM REPAIR

BACKGROUND

Abdominal aortic aneurysm repair is associated with significant morbidity and mortality. This study aims to evaluate the efficiency of scoring systems in a group of patients undergoing abdominal aortic aneurysm repair.

METHODS

A prospective study of 152 patients undergoing aneurysm repair was conducted. Each patient was scored according to the Acute Physiology and Chronic Health Evaluation II, Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity and Simplified Acute Physiology Score II systems. The predicted mortality for each patient was calculated. Chi(2) analysis was carried out to determine the accuracy of mortality predictions. Receiver-operator curves were drawn to compare scoring systems in terms of sensitivity and specificity.

RESULTS

In the elective aneurysm repair group, all scoring systems tended to overestimate mortality. Receiver-operator curves showed inaccuracies in identifying patients who were at high risk from surgery. In contrast, predicted mortalities underestimated the true death rate among the ruptured aneurysm group. Receiver-operator curves showed better efficiency of scoring systems in the ruptured aneurysm group than in the elective repair group. There was no significant correlation between predicted and observed mortalities in either group.

CONCLUSION

In this study, all systems showed significant errors when predicting mortality. Therefore, although useful as an audit tool, scoring systems should not be used on an individual basis to guide treatment and assess prognosis after surgery.

Improved survival after introduction of an emergency endovascular therapy protocol for ruptured abdominal aortic aneurysms

BACKGROUND

The study was conducted to demonstrate improved survival (30-day mortality) after the introduction of an emergency endovascular therapy protocol for ruptured abdominal aortic aneurysms (rAAA). Numerous authors have successfully demonstrated reduced mortality in patients with rAAA using endovascular techniques. Comparison of endovascular aneurysm repair (EVAR) with open repair for rAAA may be misleading, however, because EVAR cannot be performed on all patients, and selection bias may explain the superior performance of any given surgical or endovascular strategy. We developed a model to predict mortality in patients before the introduction of EVAR (preprotocol population), applied this model to predict 30-day mortality among prospective patients (postprotocol population), and compared observed vs expected results.

METHODS

We assessed 126 patients with rAAA. Primary outcome was 30-day mortality. Potential confounding variables were age, sex, presurgical lowest recorded systolic blood pressure (SBP), and glomerular filtration rate (GFR). A logistic regression model incorporating significant confounders was used to evaluate changes in 30-day mortality for all patients with rAAA after introduction of the EVAR protocol. Separate logistic regressions were done to compare 30-day mortality for preprotocol vs patients receiving EVAR and preprotocol vs patients receiving postprotocol open repair. Cumulative sum (CUSUM) analysis was used to assess shifts in the performance of the rAAA program over time.

RESULTS

Significant confounders were SBP, absence of SBP, and GFR. Logistic regression found evidence of lower mortality after the protocol was introduced, 17.9% vs 30.0% (odds ratio [OR], 0.385; 95% confidence interval [CI], 0.141 to 0.981; P = .046). Comparison of all open repairs (preprotocol and postprotocol) and EVAR demonstrated decreased risk for EVAR of 5.0% vs 28.3% (OR, 0.109; 95% CI, 0.013 to 0.906; P = .0084). Unstable patients (SBP <or=80) showed a trend towards improved survival with EVAR relative to open repair (14.3% vs 56.0%, P = .061). Comparison of preprotocol surgery with open repair after the introduction of the protocol found no evidence of a difference between mortality rates for the open procedures-30.0% (preprotocol) vs 25.0% (postprotocol; OR, 0.688; 95% CI, 0.335 to 1.415, P = .3031)-demonstrating that the improved performance observed with CUSUM analysis was related to the introduction of the EVAR protocol.

CONCLUSION

Our predictive model using "weighted" CUSUM analysis (a measure of performance over time) demonstrated that a predefined strategy of management of rAAA that includes EVAR is associated with improved (P < .05) mortality. Unstable patients with rAAA may be particularly benefited by EVAR and should not be excluded from repair. Appropriate patients with rAAA who are undergoing treatment in experienced vascular centers should be offered EVAR as the treatment of choice.

Validation of the CR-POSSUM risk-adjusted scoring system for major colorectal cancer surgery in a single center

PURPOSE

Scoring systems to predict mortality from surgery are important tools used to give information to the operator and patient and in the auditing of clinical practice. This study was designed to validate the recently developed the Colorectal Physiologic and Operative Severity Score for the Enumeration of Mortality and Morbidity (CR-POSSUM) scoring system in a single center for colorectal cancer surgery. We also analyzed whether albumin may have a role in the CR-POSSUM model.

METHODS

We compared this model with two other scoring systems: POSSUM and Portsmouth-POSSUM (P-POSSUM) models. In-hospital mortality was used as the outcome, and Hosmer-Lemeshow statistic was used to determine goodness of fit.

RESULTS

Complete data were collected prospectively from 304 patients from 1990 to the present. The overall operative mortality was 6.5 percent. Observed to expected ratios were used to compare the scoring systems at a given predicted mortality. The overall observed to expected ratio was 1.25 for CR-POSSUM, 1.59 for P-POSSUM, and 3.37 for POSSUM. The CR-POSSUM model showed a good fit with the data (Hosmer-Lemeshow statistic, 3.86; P = 0.795) and the area under the receiver operator curve was 0.74. After correcting for factors used in the CR-POSSUM, logistic regression showed a significant correlation between albumin and mortality (P = 0.016).

CONCLUSIONS

We have shown that the CR-POSSUM model is an accurate predictor of outcome for major colorectal surgery. The POSSUM and P-POSSUM models over-predicted mortality. Albumin, which is not a factor included in these three systems, may be an important addition in improving the accuracy of the CR-POSSUM model.

Evaluation of P-POSSUM and CR-POSSUM Scores in Patients with Colorectal Cancer Undergoing Resection

INTRODUCTION

The aim of this study was to evaluate the predictive accuracy of P-POSSUM and CR-POSSUM models on patients undergoing colorectal resection.

METHODS

P-POSSUM and CR-POSSUM predictor equations for mortality were applied retrospectively to 321 patients who had undergone colorectal resection for cancer. P-POSSUM and CR-POSSUM scores were validated by assessing their calibration and discrimination. Calibration was assessed using the Hosmer-Lemeshow goodness-of-fit test and the corresponding calibration curves. Evaluation of the discriminative capability of both models was performed using receiver-operating characteristic (ROC) curve analysis.

RESULTS

Overall, 22 deaths were observed. CR-POSSUM predicted 25 deaths (chi2 = 12.20, P = 0.13), and P-POSSUM predicted 29 deaths (chi2 =18.85, P = 0.002). ROC curves analysis revealed that CR-POSSUM has reasonable discriminatory power for mortality.

CONCLUSIONS

These data suggest that CR-POSSUM may provide a better estimate of the risk of mortality for patients who undergoing colorectal resection.