Low predictive power of comorbidity indices identified for mortality after acute arthroplasty surgery undertaken for femoral neck fracture

5-Factor Modified Frailty Index as a Predictor of Outcomes After Hemiarthroplasty or Total Hip Arthroplasty for Femoral Neck Fracture

INTRODUCTION

Although the 5-factor modified frailty index (mFI-5) has been shown to be an independent predictor of complications after primary total hip arthroplasty (THA), its predictive value has not been evaluated in the setting of hip fracture. We therefore assessed the utility of mFI-5 score as an independent predictor of morbidity and mortality in patients who underwent THA or hemiarthroplasty for femoral neck fracture.

METHODS

The American College of Surgeons National Surgical Quality Improvement database was queried for all patients with femoral neck fractures treated with THA or hemiarthroplasty between 2006 and 2020. A multivariate logistic regression analysis was done using mFI-5 as a predictor while controlling for baseline demographic and clinical variables.

RESULTS

In total, 45,185 patients (hemiarthroplasty: 37,645; THA: 7,540) were identified. For hemiarthroplasty patients, the mFI-5 strongly predicted risk of any complication (OR, 1.1; 95% CI, 1.1 to 1.2; P < 0.001), bleeding (OR, 1.2; 95% CI, 1.1 to 1.3; P < 0.001), and readmission (OR, 1.2; 95% CI, 1.1 to 1.3; P < 0.001). For THA patients, the mFI-5 was a strong predictor of any complication (OR, 1.2; 95% CI, 1.0 to 1.3; P = 0.023), pneumonia (OR, 1.4; 95% CI, 1.0 to 2.0; P = 0.047), and readmission (OR, 1.3; 95% CI, 1.1 to 1.6; P = 0.004).

DISCUSSION

The mFI-5 is an independent predictor of morbidity and complications after hemiarthroplasty and THA for femoral neck fracture. Importantly, readmission risk was predicted by the mFI-5. The mFI-5 may present a valuable clinical tool for assessment of high-risk patients who might require additional resources and specialized care after femoral neck fracture.

Any infection among patients with hip fracture: Predictive ability of Charlson, Elixhauser, Rx-Risk, and Nordic comorbidity indices

BACKGROUND

In studies on infection after hip fracture surgery, a common and serious complication, it remains unknown which comorbidity index is best for case-mix confounder adjustment. We evaluated the predictive ability of Charlson Comorbidity Index (CCI), Elixhauser Comorbidity Index (ECI), Rx-Risk Index (Rx-Risk), and Nordic Multimorbidity Index (NMI) for any infection up to 1 year from discharge after hip fracture surgery.

METHODS

Using Danish medical registries, we included 92,600 patients (mean age 83 years) surgically treated for hip fracture between 2004 and 2018. Comorbidity-index scores were calculated using prevalence of diagnosis codes, prescription codes, or both. Lookback periods of 1, 5, and 10 years were applied. Logistic regression was used to calculate c-index to assess discrimination of comorbidity indices individually and in combination with a base model of age and sex. Outcome was any infection (not only surgical site infection) in-hospital and 1 year after discharge.

RESULTS

At 10-year lookback period, the c-index for individual comorbidity indices for in-hospital infections varied from 0.53 to 0.56, similar to base model alone (0.56). The predictive ability of comorbidity indices in combination with base model varied from 0.56 to 0.57. Within 1 year after discharge, NMI in combination with base model had best predictive ability for infection (c-index = 0.62), followed by CCI and ECI (c-index = 0.60) and Rx-Risk (c-index = 0.58). Discrimination was similar for all lookback periods.

CONCLUSIONS

Comorbidity indices have low predictive ability for any infection up to 1 year after hip fracture surgery, similar to that of age and sex alone. For case-mix adjustment, evaluated comorbidity indices are of equal value.

Albumin is an Independent Predictor of up to 9-Year Mortality for Intracapsular Femoral Neck Fractures Aiding in Decision-Making for Total Hip Arthroplasty or Hemiarthroplasty

BACKGROUND

Intracapsular femoral neck fractures in the geriatric population are usually treated with hemiarthroplasty or total hip arthroplasty. The patients' medium-term to long-term mortality is a consideration to help decide which procedure to perform. The aim of this study is to examine whether easily identifiable serum investigations and patient identifiable factors on admission are associated with medium-term and long-term mortality.

METHODS

A consecutive series of 331 patients who sustained intracapsular femoral neck fractures and were over the age of 55 years were identified and retrospectively reviewed. American Society of Anesthesiologists (ASA) grade, cognitive function, gender, age, mobility status, and admission serum investigations were considered.

RESULTS

Low albumin levels, advanced age, men, and a combination of high ASA with lower mobility status were independent predictors of mean 5-year mortality. Similarly, low albumin levels and a combination of high ASA with lower mobility status were found to be independent predictors of longer term mortality (7-9 years). The optimal albumin cut-off to identify patient survival was >42 g/L with an area under the curve of 0.71.

CONCLUSION

We suggest that serum albumin on admission can be utilized as a factor to identify patients who are likely to survive at up to 9-year mean follow-up, to guide decision for total hip arthroplasty over hemiarthroplasty.

Risk prediction models incorporating institutional case volume for mortality after hip fracture surgery in the elderly

INTRODUCTION

While higher institutional case volume is associated with better postoperative outcomes in various types of surgery, institutional case volume has been rarely included in risk prediction models for surgical patients. This study aimed to develop and validate the predictive models incorporating institutional case volume for predicting in-hospital mortality and 1-year mortality after hip fracture surgery in the elderly.

MATERIALS AND METHODS

Data for all patients (≥ 60 years) who underwent surgery for femur neck fracture, pertrochanteric fracture, or subtrochanteric fracture between January 2008 and December 2016 were extracted from the Korean National Health Insurance Service database. Patients were randomly assigned into the derivation cohort or the validation cohort in a 1:1 ratio. Risk prediction models for in-hospital mortality and 1-year mortality were developed in the derivation cohort using the logistic regression model. Covariates included age, sex, type of fracture, type of anaesthesia, transfusion, and comorbidities such as hypertension, diabetes, coronary artery disease, chronic kidney disease, cerebrovascular disease, and dementia. Two separate models, one with and the other without institutional case volume as a covariate, were constructed, evaluated, and compared using the likelihood ratio test. Based on the models, scoring systems for predicting in-hospital mortality and 1-year mortality were developed.

RESULTS

Analysis of 196,842 patients showed 3.6% in-hospital mortality (7084/196,842) and 15.42% 1-year mortality (30,345/196,842). The model for predicting in-hospital mortality incorporating the institutional case volume demonstrated better discrimination (c-statistics 0.692) compared to the model without the institutional case volume (c-statistics 0.688; likelihood ratio test p value < 0.001). The performance of the model for predicting 1-year mortality was also better when incorporating institutional case volume (c-statistics 0.675 vs. 0.674; likelihood ratio test p value < 0.001).

CONCLUSIONS

The new institutional case volume incorporated scoring system may help to predict in-hospital mortality and 1-year mortality after hip fracture surgery in the elderly population.

Glucose dysregulation and its association with COVID-19 mortality and hospital length of stay

BACKGROUND AND AIMS

We investigate the impact of blood glucose on mortality and hospital length of stay (HLOS) among COVID-19 patients.

METHODS

Retrospective study of 456 patients with confirmed COVID-19 and glycemic dysregulation in the New York City area.

RESULTS

We found that impaired glucose adjusted for other organs systems involved (OR:1.87; 95% CI:1.36-2.57, p < 0.001), increased glucose nadir (OR:34.28; 95% CI:3.97-296.05, p < 0.01) and abnormal blood glucose levels at discharge (OR:5.07; 95% CI:2.31-11.14, p < 0.001) were each significantly associated with increased odds for mortality. New or higher from baseline insulin requirement during hospitalization (OR:0.34; 95% CI:0.15-0.78; p < 0.05) was significantly associated with decreased odds for mortality. Increased glucose peak (B = 0.001, SE=<0.001, p < 0.001), new or higher from baseline insulin requirement during hospitalization (B = 0.11, SE = 0.03, p < 0.001), and increased days to dysglycemia (B = 0.15, SE = 0.04, p < 0.001) were each significantly associated with increased HLOS. Increased glucose nadir (B = -0.67, SE = 0.07, p < 0.001), insulin intravenous drip (B = -0.10, SE = 0.05, p < 0.05), and increased proportion days endocrine system involved (B = -0.25, SE = 0.06, p < 0.001) were each significantly associated with decreased HLOS.

CONCLUSION

Glucose dysregulation adversely affects mortality and HLOS in COVID-19. These data can help clinicians to guide patient treatment and management in COVID-19 patients.

Hip arthroplasty for acute hip fracture in patients with neurological disorders: A report Of 9,702 cases from the Swedish arthroplasty register

INTRODUCTION

The purpose of this study was to investigate neurological disorder as a risk factor for dislocation following arthroplasty for acute hip fractures. We also analysed medical and surgical adverse events (AE), readmission, reoperation, revision, and mortality as secondary outcomes.

METHODS

A longitudinal cohort study using prospectively collected and aggregated data from the Swedish Hip Arthroplasty Register (SHAR) and the Swedish national patient register. All patients presenting with an acute hip fracture and treated with an arthroplasty in the period from 2005 to 2014 from the SHAR were identified. Patients in receipt of bilateral arthroplasties were excluded. Patients with a relevant pre-existing and diagnosed neurological disorder, as defined by ICD-10 codes, were identified (n = 9,702). All other cases (n = 29,411) were available for logistic regression propensity score matching. Patients were 1:1 matched on age, sex, Charlson comorbidity index, total versus hemiarthroplasty, head size, surgical approach, and year of surgery. Dislocations, adverse events, readmission, reoperation, revision, and mortality were studied using Kaplan-Meier analysis and Cox regression.

RESULTS

The risk of dislocations was higher for patients with neurological disorder (HR=1.19, CI 1.03- 1.39, p<0.05). Neurological disorder was associated with increased risk of encountering an adverse event (p<0.001 at 90-days); these patients were at higher risk of dying (HR=1.51, CI 1.47-1.56, p<0.001) however they were less likely to be readmitted (HR=0.73, CI 0.70- 0.76, p<0.001). No excess risks of reoperation (HR=1.02, CI 0.90-1.17; p = 0.73) or revision (HR=1.00, CI 0.86-1.17; p = 0.99) were identified in the study group.

DISCUSSION

Compared to matched controls, individuals with a preoperatively identified neurological diagnosis had higher rates of mortality, dislocations, and adverse events, but this cohort was not at increased risk of reoperation or revision. This study highlights an area of focus for future research to improve the long-term outcomes in patients with neurological disease undergoing arthroplasty for an acute hip fracture.

Prediction Ability of Charlson, Elixhauser, and Rx-Risk Comorbidity Indices for Mortality in Patients with Hip Fracture. A Danish Population-Based Cohort Study from 2014 – 2018

Objective

Methods

Results

Conclusion

Development and validation of a model for predicting mortality in patients with hip fracture

OBJECTIVE

to develop a user-friendly prediction tool of 1-year mortality for patients with hip fracture, in order to guide clinicians and patients on appropriate targeted preventive measures.

DESIGN

population-based cohort study from 2011 to 2017 using nationwide data from the Danish Hip Fracture Registry.

SUBJECTS

a total of 28,791 patients age 65 and above undergoing surgery for a first-time hip fracture.

METHODS

patient-related prognostic factors at the time of admission were assessed as potential predictors: Nursing home residency, comorbidity (Charlson Comorbidity Index [CCI] Score), frailty (Hospital Frailty Risk Score), basic mobility (Cumulated Ambulation Score), atrial fibrillation, fracture type, body mass index (BMI), age and sex. Association with 1-year mortality examined by determining the cumulative incidence, applying univariable logistic regression and assessing discrimination (area under the receiver operating characteristics curve [AUROC]). The final model (logistic regression) was utilised on a development cohort (70% of patients). Discrimination and calibration were assessed on the validation cohort (remaining 30% of patients).

RESULTS

all predictors showed an association with 1-year mortality, but discrimination was moderate. The final model included nursing home residency, CCI Score, Cumulated Ambulation Score, BMI and age. It had an acceptable discrimination (AUROC 0.74) and calibration, and predicted 1-year mortality risk spanning from 5 to 91% depending on the combination of predictors in the individual patient.

CONCLUSIONS

using information obtainable at the time of admission, 1-year mortality among patients with hip fracture can be predicted. We present a user-friendly chart for daily clinical practice and provide new insight regarding the interplay between prognostic factors.

Increased mortality after intramedullary nailing of trochanteric fractures: a comparison of sliding hip screws with nails in 19,935 patients

Background and purpose - Intramedullary nails (IMN) have become increasingly common as treatment for trochanteric hip fractures (THF) although they are costlier, and without proven superiority compared with sliding hip screws (SHS). We investigated whether the 2 methods differ in terms of short-term mortality when used in fractures where both methods are suitable. Patients and methods - We extracted data from the Swedish Fracture Register (SFR) on 19,935 patients ≥ 60 years with trochanteric fractures AO type 31-A1 or -A2 who had been treated with either SHS or IMN. We assessed absolute mortality rates and the relative risks (RR) of death after 7, 30, 90, and 365 days using generalized linear models, adjusting for age, sex, and fracture type. We performed a sensitivity analysis on a subgroup of 3,673 patients with information on comorbidity to address this potential confounder. Results - 69% of the patients were women and mean age was 84 years (60-107). IMN was used in 35% of A1 and in 71% of A2 fractures. The use of IMN was associated with a slightly increased adjusted risk of death within 30 days compared with SHS (RR = 1.1, 95% CI 1.0-1.2) with no difference at any other time point. Interpretation - The slightly increased risk of death up to 30 days postoperatively does not support the use of IMN instead of SHS in stable THF.

Validation of the Nottingham Hip Fracture Score (NHFS) for the prediction of 30-day mortality in a Swedish cohort of hip fractures

BACKGROUND

Hip fracture is a common osteoporotic fracture with great morbidity and mortality. The utility of ASA classification is limited, as most patients are ≥ASA 3. A reliable predictor of mortality risk could support decision-making. We aimed to evaluate Nottingham hip fracture score (NHFS) for the prediction of 30-day mortality and then to recalibrate the formula converting NHFS to risk of 30-day mortality.

METHODS

All patients >60 years with surgically treated hip fracture surgery during 2015-16 were assessed. Data was extracted manually from routinely collected clinical data in registry and medical records. Discriminative performance of NHFS and ASA was assessed with C-statistics. The conversion formula from NHFS to risk of 30-day mortality was recalibrated using logistic binominal regression. Observed vs expected ratios of 30-day mortality were compared with the 2012 NHFS-formula and recalibration was performed in a split dataset.

RESULTS

1864 patients were included, with 213 deaths within 30 days. C-statistic were 0.64 for NHFS and 0.62 for ASA. Comparing expected values from the 2012-revision with our observed deaths gave a ratio of 1.37. Relating predicted levels of 30-day mortality based on 70% of our cohort vs. 30% test portion of our Swedish dataset gave a ratio of 0.97.

DISCUSSION

NHFS underestimated mortality in our cohort and showed poor discrimination. Revision of the formula based on a split dataset improved calibration. We suggest NHFS to be routinely implemented to support clinical judgements, expand preoperative assessment and escalate intraoperative monitoring.

Waiting time for hip fracture surgery: hospital variation, causes, and effects on postoperative mortality : data on 37,708 operations reported to the Norwegian Hip fracture Register from 2014 to 2018

Aims

This study aimed to describe preoperative waiting times for surgery in hip fracture patients in Norway, and analyze factors affecting waiting time and potential negative consequences of prolonged waiting time.

Methods

Overall, 37,708 hip fractures in the Norwegian Hip Fracture Register from January 2014 to December 2018 were linked with data in the Norwegian Patient Registry. Hospitals treating hip fractures were characterized according to their hip fracture care. Waiting time (hours from admission to start of surgery), surgery within regular working hours, and surgery on the day of or on the day after admission, i.e. ‘expedited surgery’ were estimated.

Results

Mean waiting time was 22.6 hours (SD 20.7); 36,652 patients (97.2%) waited less than three days (< 72 hours), and 27,527 of the patients (73%) were operated within regular working hours (08:00 to 16:00). Expedited surgery was given to 31,675 of patients (84%), and of these, 19,985 (53%) were treated during regular working hours. Patients classified as American Society of Anesthesiologists (ASA) classes 4 and 5 were more likely to have surgery within regular working hours (odds ratio (OR) 1.59; p < 0.001), and less likely to receive expedited surgery than ASA 1 patients (OR 0.29; p < 0.001). Low-volume hospitals treated a larger proportion of patients during regular working hours than high volume hospitals (OR 1.26; p < 0.001). High-volume hospitals had less expedited surgery and significantly longer waiting times than low and intermediate-low volume hospitals. Higher ASA classes and Charlson Comorbidity Index increased waiting time. Patients not receiving expedited surgery had higher 30-day and one-year mortality rates (OR 1.19; p < 0.001) and OR 1.13; p < 0.001), respectively.

Conclusion

There is inequality in waiting time for hip fracture treatment in Norway. Variations in waiting time from admission to hip fracture surgery depended on both patient and hospital factors. Not receiving expedited surgery was associated with increased 30-day and one-year mortality rates.

Cite this article: Bone Jt Open 2021;2(9):710–720.

The ability of comorbidity indices to predict mortality in an orthopedic setting: a systematic review

BACKGROUND

Several comorbidity indices have been created to estimate and adjust for the burden of comorbidity. The objective of this systematic review was to evaluate and compare the ability of different comorbidity indices to predict mortality in an orthopedic setting.

METHODS

A systematic search was conducted in Embase, MEDLINE, and Cochrane Library. The search were constructed around two primary focal points: a comorbidity index and orthopedics. The last search were performed on 13 June 2019. Eligibility criteria were participants with orthopedic conditions or who underwent an orthopedic procedure, a comparison between comorbidity indices that used administrative data, and reported mortality as outcome. Two independent reviewers screened the studies using Covidence. The area under the curve (AUC) was chosen as the primary effect estimate.

RESULTS

Of the 5338 studies identified, 16 met the eligibility criteria. The predictive ability of the different comorbidity indices ranged from poor (AUC < 0.70) to excellent (AUC ≥ 0.90). The majority of the included studies compared the Elixhauser Comorbidity Index (ECI) and the Charlson Comorbidity Index (CCI). In-hospital mortality was reported in eight studies reporting AUC values ranging from 0.70 to 0.92 for ECI and 0.68 to 0.89 for CCI. AUC values were generally lower for all other time points ranging from 0.67 to 0.78. For 1-year mortality the overall effect size ranging from 0.67 to 0.77 for ECI and 0.69 to 0.77 for CCI.

CONCLUSION

The results of this review indicate that the ECI and CCI can equally be used to adjust for comorbidities when analyzing mortality in an orthopedic setting.

TRIAL REGISTRATION

The protocol for this systematic review was registered on PROSPERO, the International Prospective Register of Systematic Reviews on 13 June 2019 and can be accessed through record ID 133,871.

The prognostic implication of perioperative cardiac enzyme elevation in patients with fractured neck of femur: A systematic review and meta-analysis

BACKGROUND

Neck of Femur (NOF) fractures are a common injury in comorbid elderly patients which are associated with increased rates of morbidity and mortality following fracture. Because of their injury, patients can experience reductions in quality of life and independent living leading to transfer to nursing home or dependent levels of care. Numerous factors are associated with either complications or reductions in survival following fractured NOF. From the VISION cohort there is evidence that troponin elevation in the post-operative period following a diverse range of non-cardiac surgical procedures may lead to an increased risk of mortality in the absence of classical ischaemic or cardiac symptoms. The aim of this systematic review and meta-analysis is to validate the utility of perioperative troponin elevation as a prognostic indicator for mortality and cardiac morbidity in those with fractured NOF.

METHODS

The PRISMA guidelines for the conduct of meta-analyses were followed. An electronic search was conducted of the EMBASE, MEDLINE (Ovid) and Biosis databases. Studies were included for analysis if they stratified outcomes by perioperative troponin elevation in surgically managed fractured NOF and reported sufficient data on troponin elevation and mortality following surgery. Primary and secondary outcomes assessed were all-cause post-operative mortality and a composite measure of cardiac complications (myocardial infarction, cardiac failure and arrhythmia) respectively.

RESULTS

Eleven studies met inclusion criteria giving a total of 1363 patients. Overall, 497 patients (36.5%) experienced an elevation in troponin levels following surgery. Perioperative troponin elevation was significantly associated with all-cause mortality (OR 2.6; 95% CI 1.5 - 4.6; p <0.001) and cardiac complications (OR 7.4; 95% CI 3.5 - 15.8; p <0.001). Patient factors significantly associated with troponin elevation included pre-existing coronary artery disease, cardiac failure, hypertension, previous stroke and previous myocardial infarction.

CONCLUSION

Perioperative troponin elevation is significantly associated with increased mortality and post-operative cardiac complications following fractured NOF and may be a useful prognostic indicator in these patients. Future research should further stratify patients by the magnitude of troponin elevation and further refine the risk factors.

Reduced Revision Risk for Dual-Mobility Cup in Total Hip Replacement Due to Hip Fracture: A Matched-Pair Analysis of 9,040 Cases from the Nordic Arthroplasty Register Association (NARA)

BACKGROUND

The dual-mobility acetabular cup (DMC) has an additional bearing consisting of a mobile polyethylene component between the prosthetic head and the outer metal shell. This design has gained popularity in revision total hip arthroplasty (THA) and in primary treatment of femoral neck fractures with the anticipation of a reduced risk of THA instability. Our primary aim was to evaluate the overall revision risk of these cups on the basis of data from the Nordic Arthroplasty Register Association (NARA) database, and our secondary aim was to study specific revision causes including dislocation.

METHODS

Propensity score matching for age, sex, fixation of the cup and stem, and the year of surgery (2001 to 2014) was used to match 4,520 hip fractures treated with a DMC to 4,520 hip fractures treated with conventional THA (control group). Competing risk regression analyses with revision or death as the end point were used. Revision was defined as a secondary surgical procedure in which any component of the implant was removed or exchanged. In addition, revision of the cup was analyzed.

RESULTS

The DMCs had a lower risk of revision compared with conventional THA, with an adjusted hazard ratio (AHR) of 0.75 (95% confidence interval [CI] = 0.62 to 0.92). This was consistent after adjusting for surgical approach. DMCs had a lower risk of revision due to dislocation (AHR = 0.45 [95% CI = 0.30 to 0.68]) but we found no difference regarding revision for deep infection. Revision of the acetabular component, both in general and due to dislocation, was more frequent with the use of conventional cups. The risk of death was higher in the DMC group (AHR = 1.49 [95% CI = 1.40 to 1.59]).

CONCLUSIONS

The use of a DMC as primary treatment for hip fracture was associated with a lower risk of revision in general and due to dislocation in particular. The total number of DMCs analyzed (4,520) likely exceeds any cohort of DMC-treated fractures published to date.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.