O-POSSUM score predicts morbidity and mortality in patients undergoing hip fracture surgery

O-POSSUM and P-POSSUM as predictors of morbidity and mortality in older patients after hip fracture surgery: a meta-analysis

BACKGROUND

The POSSUM model has been widely used to predict morbidity and mortality after general surgery. Modified versions known as O-POSSUM and P-POSSUM have been used extensively in orthopedic surgery, but their accuracy is unclear. This systematic review evaluated the predictive value of these models in older patients with hip fractures.

METHODS

This study was performed and reported based on the "Preferred reporting items for systematic reviews and meta-analyses" guidelines. PubMed, Cochrane, EMBASE, and Web of Science were comprehensively searched for relevant studies, whose methodological quality was evaluated according to the "Methodological index for non-randomized studies" scale. Revman 5 was used to calculate weighted ratios of observed to expected morbidity or mortality.

RESULTS

The meta-analysis included 10 studies, of which nine (2549 patients) assessed the ability of O-POSSUM to predict postoperative morbidity, nine (3649 patients) assessed the ability of O-POSSUM to predict postoperative mortality, and four (1794 patients) assessed the ability of P-POSSUM to predict postoperative mortality. The corresponding weighted ratios of observed to expected morbidity or mortality were 0.84 (95% CI 0.70-1.00), 0.68 (95% CI 0.49-0.95), and 0.61 (95% CI 0.16-2.38).

CONCLUSIONS

While O-POSSUM shows reasonable accuracy in predicting postoperative morbidity in older patients with hip fractures, both P-POSSUM and O-POSSUM substantially overestimate postoperative mortality. The POSSUM model should be optimized further for this patient population.

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.

A new preoperative risk score for predicting mortality of elderly hip fracture patients: an external validation study

BACKGROUND

Hip fractures are common in the elderly and have a high risk of mortality. Several risk prediction models for mortality of hip fracture have been developed, but most of them are difficult to apply accurately in clinical practice.

AIMS

The objective of the present study was to perform an external validation of a new published preoperative risk score for predicting mortality.

METHODS

We carried out a retrospective cohort study from January 2014 to December 2018 for elderly hip fracture patients discharged from a orthopedic center in China. The preoperative risk score was calculated for each patient, and further divided into two groups: low-risk group (score < 24 points) and high-risk group (score ≥ 24 points) using the receiver operating characteristic (ROC) curve. The outcome was 30-day, 6-month and 1-year all-cause mortality, and the relationship between the risk score and mortality was assessed by univariate and multivariate Cox proportional hazard models. The area under the curve (AUC), Hosmer-Lemeshow test and calibration plots were used to test the discrimination and calibration.

RESULTS

A total of 460 consecutive patients were included in the study, and high-risk score was an independent risk factor for 30-day mortality [Hazard ratio (HR) 6.70; 95% Confidence interval (CI) 1.82-24.69; p = 0.004], 6-month mortality (HR 2.94; 95% CI 1.68-5.17; p < 0.001) and 1-year mortality (HR 3.30; 95% CI 2.09-5.20; p < 0.001). Also, each point increase in the risk score resulted in a 11% increase in 30-day mortality (HR 1.11; 95% CI 1.07-1.16; p < 0.001), 6% increase in 6-month mortality (HR 1.06; 95% CI 1.04-1.09; p < 0.001), and 5% increase in 1-year mortality (HR 1.05; 95% CI 1.03-1.07; p < 0.001). Moreover, the risk score had an AUC of 0.89 (95% CI 0.80-0.98) for 30-day mortality, 0.77 (95% CI 0.70-0.83) for 6-month mortality, and 0.76 (95% CI 0.70-0.81) for 1-year mortality. Calibration plots showed a good calibration between observed and predicted mortality, which was also demonstrated by the Hosmer-Lemeshow test.

CONCLUSION

Our present study findings indicated that the preoperative risk score was an accurate mortality risk assessment tool for elderly hip fracture patients, regardless of short- and long-term follow-up.