Postoperative mortality in hip fracture patients stratified by the Revised Cardiac Risk Index: a Swedish nationwide retrospective cohort study

Association of the Revised Cardiac Risk Index with 1-year postoperative mortality: A single-center retrospective study

OBJECTIVE

To explore risk factors for 1-year postoperative mortality and to identify its association with the Revised Cardiac Risk Index (RCRI).

METHODS

This was a retrospective cohort study involving 54,933 patients aged 18 years and above who were surgically treated under general or regional anesthesia in a tertiary hospital in Singapore. Independent risk factors for 1-year postoperative mortality were identified by univariate Cox regression analysis. The association between the RCRI and 1-year postoperative mortality was assessed by the Kaplan-Meier estimator and multivariate Cox regression analysis and was further validated in subgroup analyses stratified by the sex, age, and type of anesthesia.

RESULTS

A total of 54,933 eligible patients were enrolled in this study that included 23,922 patients classified as RCRI Class I, 25,979 as Class II, 3700 as Class III, and 1332 as Class IV. Cox regression analysis demonstrated that male sex, age, higher American Society of Anesthesiologists (ASA) physical status classification level, regional anesthesia, emergency surgery, degree of anemia, and increased RCRI were significantly associated with the increased risk of 1-year postoperative mortality (HR > 1, all P < 0.001). The significant association between RCRI and 1-year postoperative mortality still existed after adjusting for confounding factors. An RCRI Class IV was associated with a mortality risk greater than two-fold larger than that observed at an RCRI Class I (adjusted HR 2.14, 95 % CI 1.78 to 2.56, p < 0.001). Subgroup analyses revealed that the 1-year postoperative mortality was significantly higher in patients with RCRI Class IV than that of Classes I-III regardless of the sex, age, and type of anesthesia.

CONCLUSION

RCRI is significantly correlated with 1-year postoperative mortality regardless of sex, age, and type of anesthesia. Further studies to validate these findings are warranted.

Risk factors and nomogram predictive model of severe postoperative complications in elderly patients with intertrochanteric fractures

Objective

To analyze risk factors of severe postoperative complications in elderly patients with intertrochanteric fractures (ITF), and to construct a predictive model.

Methods

The medical records of 316 elderly patients with ITF who underwent surgical treatment in Suzhou Hospital of Integrated Traditional Chinese and Western Medicine from January 2020 to December 2022 were retrospectively analyzed. Univariate and multivariate logistic regression analyses were performed to identify risk factors of severe postoperative complications. A nomogram prediction model was constructed using the RMS package of R4.1.2 software. Accuracy and stability of the model was assessed using the receiver operating characteristic (ROC) curve, Hosmer-Lemeshow goodness-of-fit test, and decision curve analysis.

Results

Age, American Society of Anesthesiologists (ASA) grading, combined medical diseases, preoperative bedridden condition, frailty, and preoperative albumin levels were all risk factors for severe postoperative complications in ITF patients were noted. These factors were then used to build a risk prediction model that had an area under the ROC curve (AUC) of 0.899 (95% confidence interval (CI): 0.846-0.951). The internal validation results of the Bootstrap method showed that the C-index value of the model was 0.899, and the calibration curve had a good fit with the ideal curve.

Conclusions

Age, ASA grading, combined medical diseases, preoperative bedridden condition, frailty, and preoperative albumin levels were independent risk factors for severe postoperative complications in elderly ITF patients. The constructed prediction model based on the above risk factors has a high predictive value.

Comparative Analysis of Frailty Scores for Predicting Adverse Outcomes in Hip Fracture Patients: Insights from the United States National Inpatient Sample

The aim of the current investigation was to compare the ability of several frailty scores to predict adverse outcomes in hip fracture patients. All adult patients (18 years or older) who suffered a hip fracture due to a fall and underwent surgical fixation were extracted from the 2019 National Inpatient Sample (NIS) Database. A combination of logistic regression and bootstrapping was used to compare the predictive ability of the Orthopedic Frailty Score (OFS), the Nottingham Hip Fracture Score (NHFS), the 11-factor modified Frailty Index (11-mFI) and 5-factor (5-mFI) modified Frailty Index, as well as the Johns Hopkins Frailty Indicator. A total of 227,850 patients were extracted from the NIS. In the prediction of in-hospital mortality and failure-to-rescue (FTR), the OFS surpassed all other frailty measures, approaching an acceptable predictive ability for mortality [AUC (95% CI): 0.69 (0.67-0.72)] and achieving an acceptable predictive ability for FTR [AUC (95% CI): 0.70 (0.67-0.72)]. The NHFS demonstrated the highest predictive ability for predicting any complication [AUC (95% CI): 0.62 (0.62-0.63)]. The 11-mFI exhibited the highest predictive ability for cardiovascular complications [AUC (95% CI): 0.66 (0.64-0.67)] and the NHFS achieved the highest predictive ability for delirium [AUC (95% CI): 0.69 (0.68-0.70)]. No score succeeded in effectively predicting venous thromboembolism or infections. In summary, the investigated frailty scores were most effective in predicting in-hospital mortality and failure-to-rescue; however, they struggled to predict complications.

Cardiac risk stratification and adverse outcomes in surgically managed patients with isolated traumatic spine injuries

INTRODUCTION

As the incidence of traumatic spine injuries has been steadily increasing, especially in the elderly, the ability to categorize patients based on their underlying risk for the adverse outcomes could be of great value in clinical decision making. This study aimed to investigate the association between the Revised Cardiac Risk Index (RCRI) and adverse outcomes in patients who have undergone surgery for traumatic spine injuries.

METHODS

All adult patients (18 years or older) in the 2013-2019 TQIP database with isolated spine injuries resulting from blunt force trauma, who underwent spinal surgery, were eligible for inclusion in the study. The association between the RCRI and in-hospital mortality, cardiopulmonary complications, and failure-to-rescue (FTR) was determined using Poisson regression models with robust standard errors to adjust for potential confounding.

RESULTS

A total of 39,391 patients were included for further analysis. In the regression model, an RCRI ≥ 3 was associated with a threefold risk of in-hospital mortality [adjusted IRR (95% CI): 3.19 (2.30-4.43), p < 0.001] and cardiopulmonary complications [adjusted IRR (95% CI): 3.27 (2.46-4.34), p < 0.001], as well as a fourfold risk of FTR [adjusted IRR (95% CI): 4.27 (2.59-7.02), p < 0.001], compared to RCRI 0. The risk of all adverse outcomes increased stepwise along with each RCRI score.

CONCLUSION

The RCRI may be a useful tool for identifying patients with traumatic spine injuries who are at an increased risk of in-hospital mortality, cardiopulmonary complications, and failure-to-rescue after surgery.

Prioritizing patients for hip fracture surgery: the role of frailty and cardiac risk

Introduction

The number of patients with hip fractures continues to rise as the average age of the population increases. Optimizing outcomes in this cohort is predicated on timely operative repair. The aim of this study was to determine if patients with hip fractures who are frail or have a higher cardiac risk suffer from an increased risk of in-hospital mortality when surgery is postponed >24 h.

Methods

All patients registered in the 2013-2021 TQIP dataset who were ≥65 years old and underwent surgical fixation of an isolated hip fracture caused by a ground-level fall were included. Adjustment for confounding was performed using inverse probability weighting (IPW) while stratifying for frailty with the Orthopedic Frailty Score (OFS) and cardiac risk using the Revised Cardiac Risk Index (RCRI). The outcome was presented as the absolute risk difference in in-hospital mortality.

Results

A total of 254,400 patients were included. After IPW, all confounders were balanced. A delay in surgery was associated with an increased risk of in-hospital mortality across all strata, and, as the degree of frailty and cardiac risk increased, so too did the risk of mortality. In patients with OFS ≥4, delaying surgery >24 h was associated with a 2.33 percentage point increase in the absolute mortality rate (95% CI: 0.57-4.09, p = 0.010), resulting in a number needed to harm (NNH) of 43. Furthermore, the absolute risk of mortality increased by 4.65 percentage points in patients with RCRI ≥4 who had their surgery delayed >24 h (95% CI: 0.90-8.40, p = 0.015), resulting in a NNH of 22. For patients with OFS 0 and RCRI 0, the corresponding NNHs when delaying surgery >24 h were 345 and 333, respectively.

Conclusion

Delaying surgery beyond 24 h from admission increases the risk of mortality for all geriatric hip fracture patients. The magnitude of the negative impact increases with the patient's level of cardiac risk and frailty. Operative intervention should not be delayed based on frailty or cardiac risk.

Validation of the orthopedic frailty score for measuring frailty in hip fracture patients: a cohort study based on the United States National inpatient sample

BACKGROUND

The Orthopedic Frailty Score (OFS) has been proposed as a tool for measuring frailty in order to predict short-term postoperative mortality in hip fracture patients. This study aims to validate the OFS using a large national patient register to determine its relationship with adverse outcomes as well as length of stay and cost of hospital stay.

METHODS

All adult patients (18 years or older) registered in the 2019 National Inpatient Sample Database who underwent emergency hip fracture surgery following a traumatic fall were eligible for inclusion. The association between the OFS and mortality, complications, and failure-to-rescue (FTR) was determined using Poisson regression models adjusted for potential confounders. The relationship between the OFS and length of stay and cost of hospital stay was instead determined using a quantile regression model.

RESULTS

An estimated 227,850 cases met the study inclusion criteria. There was a stepwise increase in the rate of complications, mortality, and FTR for each additional point on the OFS. After adjusting for potential confounding, OFS 4 was associated with an almost ten-fold increase in the risk of in-hospital mortality [adjusted IRR (95% CI): 10.6 (4.02-27.7), p < 0.001], a 38% increased risk of complications [adjusted IRR (95% CI): 1.38 (1.03-1.85), p = 0.032], and an almost 11-fold increase in the risk of FTR [adjusted IRR (95% CI): 11.6 (4.36-30.9), p < 0.001], compared to OFS 0. Patients with OFS 4 also required a day and a half additional care [change in median length of stay (95% CI): 1.52 (0.97-2.08), p < 0.001] as well as cost approximately $5,200 more to manage [change in median cost of stay (95% CI): 5166 (1921-8411), p = 0.002], compared to those with OFS 0.

CONCLUSION

Patients with an elevated OFS display a substantially increased risk of mortality, complications, and failure-to-rescue as well as a prolonged and more costly hospital stay.

A nationwide analysis on the interaction between frailty and beta-blocker therapy in hip fracture patients

INTRODUCTION

Hip fracture patients, who are often frail, continue to be a challenge for healthcare systems with a high postoperative mortality rate. While beta-blocker therapy (BBt) has shown a strong association with reduced postoperative mortality, its effect in frail patients has yet to be determined. This study's aim is to investigate how frailty, measured using the Orthopedic Hip Frailty Score (OFS), modifies the effect of preadmission beta-blocker therapy on mortality in hip fracture patients.

METHODS

This retrospective register-based study included all adult patients in Sweden who suffered a traumatic hip fracture and subsequently underwent surgery between 2008 and 2017. Treatment effect was evaluated using the absolute risk reduction (ARR) in 30-day postoperative mortality when comparing patients with (BBt+) and without (BBt-) ongoing BBt. Inverse probability of treatment weighting (IPTW) was used to reduce potential confounding when examining the treatment effect. Patients were stratified based on their OFS (0, 1, 2, 3, 4 and 5) and the treatment effect was also assessed within each stratum.

RESULTS

A total of 127,305 patients were included, of whom 39% had BBt. When IPTW was performed, there were no residual differences in observed baseline characteristics between the BBt+ and BBt- groups, across all strata. This analysis found that there was a stepwise increase in the ARRs for each additional point on the OFS. Non-frail BBt+ patients (OFS 0) exhibited an ARR of 2.2% [95% confidence interval (CI) 2.0-2.4%, p < 0.001], while the most frail BBt+ patients (OFS 5) had an ARR of 24% [95% CI 18-30%, p < 0.001], compared to BBt- patients within the same stratum.

CONCLUSION

Beta-blocker therapy is associated with a reduced risk of 30-day postoperative mortality in frail hip fracture patients, with a greater effect being observed with higher Orthopedic Hip Frailty Scores.

The revised cardiac risk index is associated with morbidity and mortality independent of injury severity in elderly patients with rib fractures

BACKGROUND

Risk factors for mortality and in-hospital morbidity among geriatric patients with traumatic rib fractures remain unclear. Such patients are often frail and demonstrate a high comorbidity burden. Moreover, outcomes anticipated by current rubrics may reflect the influence of multisystem injury or surgery, and thus not apply to isolated injuries in geriatric patients. We hypothesized that the Revised Cardiac Risk Index (RCRI) may assist in risk-stratifying geriatric patients following rib fracture.

METHODS

All geriatric patients (age ≥65 years) with a conservatively managed rib fracture owing to an isolated thoracic injury (thorax AIS ≥1), in the 2013-2019 TQIP database were assessed including demographics and outcomes. The association between the RCRI and in-hospital morbidity as well as mortality was analyzed using Poisson regression models while adjusting for potential confounders.

RESULTS

96,750 geriatric patients sustained rib fractures. Compared to those with RCRI 0, patients with an RCRI score of 1 had a 16% increased risk of in-hospital mortality [adjusted incidence rate ratio (adj-IRR), 95% confidence interval (CI): 1.16 (1.02-1.32), p=0.020]. An RCRI score of 2 [adj-IRR (95% CI): 1.72 (1.44-2.06), p<0.001] or ≥3 [adj-IRR (95% CI): 3.07 (2.31-4.09), p<0.001] was associated with an even greater mortality risk. Those with an increased RCRI also exhibited a higher incidence of myocardial infarction, cardiac arrest, stroke, and acute respiratory distress syndrome.

CONCLUSIONS

Geriatric patients with rib fractures and an RCRI ≥1 represent a vulnerable and high-risk group. This index may inform the decision to admit for inpatient care and can also guide patient and family counseling as well as computer-based decision-support.

Mode of anesthesia is not associated with outcomes following emergency hip fracture surgery: a population-level cohort study

Background

Hip fractures often occur in frail patients with several comorbidities. In those undergoing emergency surgery, determining the optimal anesthesia modality may be challenging, with equipoise concerning outcomes following either spinal or general anesthesia. In this study, we investigated the association between mode of anesthesia and postoperative morbidity and mortality with subgroup analyses.

Methods

This is a retrospective study using all consecutive adult patients who underwent emergency hip fracture surgery in Orebro County, Sweden, between 2013 and 2017. Patients were extracted from the Swedish National Hip Fracture Registry, and their electronic medical records were reviewed. The association between the type of anesthesia and 30-day and 90-day postoperative mortality, as well as in-hospital severe complications (Clavien-Dindo classification ≥3a), was analyzed using Poisson regression models with robust SEs, while the association with 1-year mortality was analyzed using Cox proportional hazards models. All analyses were adjusted for potential confounders.

Results

A total of 2437 hip fracture cases were included in the study, of whom 60% received spinal anesthesia. There was no statistically significant difference in the risk of 30-day postoperative mortality (adjusted incident rate ratio (IRR) (95% CI): 0.99 (0.72 to 1.36), p=0.952), 90-day postoperative mortality (adjusted IRR (95% CI): 0.88 (0.70 to 1.11), p=0.281), 1-year postoperative mortality (adjusted HR (95% CI): 0.98 (0.83 to 1.15), p=0.773), or in-hospital severe complications (adjusted IRR (95% CI): 1.24 (0.85 to 1.82), p=0.273), when comparing general and spinal anesthesia.

Conclusions

Mode of anesthesia during emergency hip fracture surgery was not associated with an increased risk of postoperative mortality or in-hospital severe complications in the study population or any of the investigated subgroups.

Level of evidence: Therapeutic/Care Management, level III

Developing and validating a scoring system for measuring frailty in patients with hip fracture: a novel model for predicting short-term postoperative mortality

Objectives

Frailty is common among patients with hip fracture and may, in part, contribute to the increased risk of mortality and morbidity after hip fracture surgery. This study aimed to develop a novel frailty score for patients with traumatic hip fracture that could be used to predict postoperative mortality as well as facilitate further research into the role of frailty in patients with hip fracture.

Methods

The Orthopedic Hip Frailty Score (OFS) was developed using a national dataset, retrieved from the Swedish National Quality Registry for Hip Fractures, that contained all adult patients who underwent surgery for a traumatic hip fracture in Sweden between January 1, 2008 and December 31, 2017. Candidate variables were selected from the Nottingham Hip Fracture Score, Sernbo Score, Charlson Comorbidity Index, 5-factor modified Frailty Index, as well as the Revised Cardiac Risk Index and ranked based on their permutation importance, with the top 5 variables being selected for the score. The OFS was then validated on a local dataset that only included patients from Orebro County, Sweden.

Results

The national dataset consisted of 126,065 patients. 2365 patients were present in the local dataset. The most important variables for predicting 30-day mortality were congestive heart failure, institutionalization, non-independent functional status, an age ≥85, and a history of malignancy. In the local dataset, the OFS achieved an area under the receiver-operating characteristic curve (95% CI) of 0.77 (0.74 to 0.80) and 0.76 (0.74 to 0.78) when predicting 30-day and 90-day postoperative mortality, respectively.

Conclusions

The OFS is a significant predictor of short-term postoperative mortality in patients with hip fracture that outperforms, or performs on par with, all other investigated indices.

Level of evidence

Level III, Prognostic and Epidemiological.

Dementia is a surrogate for frailty in hip fracture mortality prediction

Purpose

Among hip fracture patients both dementia and frailty are particularly prevalent. The aim of the current study was to determine if dementia functions as a surrogate for frailty, or if it confers additional information as a comorbidity when predicting postoperative mortality after a hip fracture.

Methods

All adult patients who suffered a traumatic hip fracture in Sweden between January 1, 2008 and December 31, 2017 were considered for inclusion. Pathological fractures, non-operatively treated fractures, reoperations, and patients missing data were excluded. Logistic regression (LR) models were fitted, one including and one excluding measurements of frailty, with postoperative mortality as the response variable. The primary outcome of interest was 30-day postoperative mortality. The relative importance for all variables was determined using the permutation importance. New LR models were constructed using the top ten most important variables. The area under the receiver-operating characteristic curve (AUC) was used to compare the predictive ability of these models.

Results

121,305 patients were included in the study. Initially, dementia was among the top ten most important variables for predicting 30-day mortality. When measurements of frailty were included, dementia was replaced in relative importance by the ability to walk alone outdoors and institutionalization. There was no significant difference in the predictive ability of the models fitted using the top ten most important variables when comparing those that included [AUC for 30-day mortality (95% CI): 0.82 (0.81–0.82)] and excluded [AUC for 30-day mortality (95% CI): 0.81 (0.80–0.81)] measurements of frailty.

Conclusion

Dementia functions as a surrogate for frailty when predicting mortality up to one year after hip fracture surgery. The presence of dementia in a patient without frailty does not appreciably contribute to the prediction of postoperative mortality.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00068-022-01960-9.

Mortality risk stratification in isolated severe traumatic brain injury using the revised cardiac risk index

PURPOSE

Traumatic brain injury (TBI) continues to be a significant cause of mortality and morbidity worldwide. As cardiovascular events are among the most common extracranial causes of death after a severe TBI, the Revised Cardiac Risk Index (RCRI) could potentially aid in the risk stratification of this patient population. This investigation aimed to determine the association between the RCRI and in-hospital deaths among isolated severe TBI patients.

METHODS

All adult patients registered in the TQIP database between 2013 and 2017 who suffered an isolated severe TBI, defined as a head AIS ≥ 3 with an AIS ≤ 1 in all other body regions, were included. Patients were excluded if they had a head AIS of 6. The association between different RCRI scores (0, 1, 2, 3, ≥ 4) and in-hospital mortality was analyzed using a Poisson regression model with robust standard errors while adjusting for potential confounders, with RCRI 0 as the reference.

RESULTS

259,399 patients met the study's inclusion criteria. RCRI 2 was associated with a 6% increase in mortality risk [adjusted IRR (95% CI) 1.06 (1.01-1.12), p = 0.027], RCRI 3 was associated with a 17% increased risk of mortality [adjusted IRR (95% CI) 1.17 (1.05-1.31), p = 0.004], and RCRI ≥ 4 was associated with a 46% increased risk of in-hospital mortality [adjusted IRR(95% CI) 1.46 (1.11-1.90), p = 0.006], compared to RCRI 0.

CONCLUSION

An elevated RCRI ≥ 2 is significantly associated with an increased risk of in-hospital mortality among patients with an isolated severe traumatic brain injury. The simplicity and bedside applicability of the index makes it an attractive choice for risk stratification in this patient population.

The consequences of out-of-hours hip fracture surgery: insights from a retrospective nationwide study

Purpose

The study aimed to investigate the association between out-of-hours surgery and postoperative mortality in hip fracture patients. Furthermore, internal fixation and arthroplasty were compared to determine if a difference could be observed in patients operated with these techniques at different times during the day.

Methods

All patients above 18 of age years in Sweden who underwent hip fracture surgery between 2008 and 2017 were eligible for inclusion. Pathological fractures, non-operatively managed fractures, or cases whose time of surgery was missing were excluded. The cohort was subdivided into on-hour (08:00–17:00) and out-of-hours surgery (17:00–08:00). Poisson regression with adjustments for confounders was used to evaluate the association between out-of-hours surgery and both 30-day and 90-day postoperative mortality.

Results

Out-of-hours surgery was associated with a 5% increase in the risk of both 30-day [adj. IRR (95% CI) 1.05 (1.00–1.10), p = 0.040] and 90-day [adj. IRR (95% CI) 1.05 (1.01–1.09), p = 0.005] mortality after hip fracture surgery compared to on-hour surgery. There was no statistically significant association between out-of-hours surgery and postoperative mortality among patients who received an internal fixation. Arthroplasties performed out-of-hours were associated with a 13% increase in 30-day postoperative mortality [adj. IRR (95% CI) 1.13 (1.04–1.23), p = 0.005] and an 8% increase in 90-day postoperative mortality [adj. IRR (95% CI) 1.08 (1.01–1.15), p = 0.022] compared to on-hour surgery.

Conclusion

Out-of-hours surgical intervention is associated with an increase in both 30- and 90-day postoperative mortality among hip fracture patients who received an arthroplasty, but not among patients who underwent internal fixation.

Predicting 1-Year Mortality after Hip Fracture Surgery: An Evaluation of Multiple Machine Learning Approaches

Postoperative death within 1 year following hip fracture surgery is reported to be up to 27%. In the current study, we benchmarked the predictive precision and accuracy of the algorithms support vector machine (SVM), naïve Bayes classifier (NB), and random forest classifier (RF) against logistic regression (LR) in predicting 1-year postoperative mortality in hip fracture patients as well as assessed the relative importance of the variables included in the LR model. All adult patients who underwent primary emergency hip fracture surgery in Sweden, between 1 January 2008 and 31 December 2017 were included in the study. Patients with pathological fractures and non-operatively managed hip fractures, as well as those who died within 30 days after surgery, were excluded from the analysis. A LR model with an elastic net regularization were fitted and compared to NB, SVM, and RF. The relative importance of the variables in the LR model was then evaluated using the permutation importance. The LR model including all the variables demonstrated an acceptable predictive ability on both the training and test datasets for predicting one-year postoperative mortality (Area under the curve (AUC) = 0.74 and 0.74 respectively). NB, SVM, and RF tended to over-predict the mortality, particularly NB and SVM algorithms. In contrast, LR only over-predicted mortality when the predicted probability of mortality was larger than 0.7. The LR algorithm outperformed the other three algorithms in predicting 1-year postoperative mortality in hip fracture patients. The most important predictors of 1-year mortality were the presence of a metastatic carcinoma, American Society of Anesthesiologists(ASA) classification, sex, Charlson Comorbidity Index (CCI) ≤ 4, age, dementia, congestive heart failure, hypertension, surgery using pins/screws, and chronic kidney disease.