The Risk Analysis Index Has Superior Discrimination Compared With the Modified Frailty Index-5 in Predicting Worse Postoperative Outcomes for the Octogenarian Neurosurgical Patient

Complementary effects of postoperative delirium and frailty on 30-day outcomes in spine surgery

BACKGROUND CONTEXT

With an increasingly older population, the number of frail patients requiring surgical management for degenerative spine diseases is rapidly increasing. Older patients are at increased risk of developing postoperative delirium (POD), which increases the odds of postoperative morbidity and mortality in spine surgery patients. Therefore, frail spine surgery patients may be at greater risk of developing POD and subsequent adverse outcomes.

PURPOSE

To understand the relationship between frailty and POD in spine surgery patients, and the effect of POD on nonfatal and fatal adverse outcomes in frail patients.

STUDY DESIGN/SETTING

Retrospective cohort study utilizing data from the 2021 American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database.

PATIENT SAMPLE

Patients aged ≥75 years undergoing spine surgery screened for POD, with a total sample size of 4,195 patients.

OUTCOME MEASURES

Primary outcomes were postoperative delirium (POD), 30-day mortality, and nonfatal adverse outcomes.

METHODS

Frailty was measured using the Risk Analysis Index (RAI) with tiered cutoffs indicating increasing frailty. Statistical methods included multivariable logistic regression and mediation analysis to evaluate the relationships between RAI, postoperative delirium, and 30-day mortality.

RESULTS

Out of 4,195 spine surgery patients aged ≥75 years screened for POD, 353 (8.4%) exhibited POD. POD patients had significantly higher RAI scores relative to those without POD (p<.001). Multivariable analysis demonstrated that increasing frailty predicted POD (p<.001). In patients with POD, there were increased odds of mortality and all nonfatal adverse outcomes within 30 days (p<.001). A complementary mediation effect of POD on frailty's contribution to 30-day mortality was observed (p<.001).

CONCLUSION

POD and increasing preoperative frailty RAI scores were independent predictors of mortality and morbidity in older spine surgery patients. POD has a significant synergistic contribution to the adverse effects of frailty following spine surgery. The RAI may be used to identify frail patients at risk of developing POD to enable optimal surgical candidate selection and provide opportunities for risk mitigation, such as prehabilitation and/or specialized perioperative care teams for frail patients.

Discriminatory Value of the Risk Analysis Index Versus the 5-Factor Modified Frailty Index for Major Outcome Measures in Degenerative Cervical Myelopathy

Study DesignObservational Retrospective Cohort Study.ObjectivesTo compare the discriminatory abilities of the Revised Risk Analysis Index (RAI-Rev) and the 5-Factor Modified Frailty Index (mFI-5) to predict major postoperative outcomes in DCM patients overall, and by anterior (ADF) or posterior (PDF) approaches for decompression and fusion.MethodsThe American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried for DCM patients undergoing ADF or PDF from 2015-2020. Logistic regression and Receiver Operating Characteristic analysis were used to compare the predictive and discriminatory value of mFI-5 and RAI-Rev for 30-day outcomes.Results18,138 DCM patients were included (median age: 61 years). Both RAI-Rev and mFI-5 predicted 30-day outcomes; however, increasing frailty as measured by RAI-Rev demonstrated greater odds ratios. RAI-rev demonstrated superior discrimination for non-fatal adverse outcomes, notably non-home discharge (NHD) [C-statistic 0.72 (95% CI 0.71-0.73, P < 0.001)], and for all non-fatal measures except major complications (P < 0.05). Sub-analysis by approach showed frailty had greater predictive accuracy for adverse outcomes in ADF compared to PDF.ConclusionsThe RAI-Rev demonstrated superior discrimination predicting non-fatal outcomes following DCM when compared to the mFI-5, with equivalent mortality prediction. Further, frailty plays a stronger role in predicting mortality and morbidity in ADF compared to frailty's impact on predicting outcomes with PDF. This finding demonstrates the utility of the RAI-Rev in preoperative risk stratification with an increasingly frail patient population and provides initial evidence for selecting posterior approaches for DCM patients as frailty increases.

Frailty Predicts 30-day mortality following major complications in neurosurgery patients: The risk analysis index has superior discrimination compared to modified frailty index-5 and increasing patient age

Background

Postoperative complications after cranial or spine surgery are prevalent, and frailty can be a key contributing patient factor. Therefore, we evaluated frailty's impact on 30-day mortality. We compared the discrimination for risk analysis index (RAI), modified frailty index-5 (mFI-5) and increasing patient age for predicting 30-day mortality.

Methods

Patients with major complications following neurosurgery procedures between 2012- 2020 in the ACS-NSQIP database were included. We employed receiver operating characteristic (ROC) curve and examined discrimination thresholds for RAI, mFI-5, and increasing patient age for 30-day mortality. Independent relationships were examined using multivariable analysis.

Results

There were 19,096 patients included in the study and in the ROC analysis for 30-day mortality, RAI showed superior discriminant validity threshold C-statistic 0.655 (95% CI: 0.644-0.666), compared to mFI-5 C-statistic 0.570 (95% CI 0.559-0.581), and increasing patient age C-statistic 0.607 (95% CI 0.595-0.619). When the patient population was divided into subsets based on the procedures type (spinal, cranial or other), spine procedures had the highest discriminant validity threshold for RAI (Cstatistic 0.717). Furthermore, there was a frailty risk tier dose response relationship with 30-day mortalityy (p<0.001).

Conclusion

When a major complication arises after neurosurgical procedures, frail patients have a higher likelihood of dying within 30 days than their non-frail counterparts. The RAI demonstrated a higher discriminant validity threshold than mFI-5 and increasing patient age, making it a more clinically relevant tool for identifying and stratifying patients by frailty risk tiers. These findings highlight the importance of initiatives geared toward optimizing frail patients, to mitigate long-term disability.

The risk analysis index demonstrates exceptional discrimination in predicting frailty's impact on neurosurgical length of stay quality metrics

BACKGROUND

Quality measures determine reimbursement rates and penalties in value-based payment models. Frailty impacts these quality metrics across surgical specialties. We compared the discriminatory thresholds for the risk analysis index (RAI), modified frailty index-5 (mFI-5) and increasing patient age for the outcomes of extended length of stay (LOS [eLOS]), prolonged LOS within 30 days (pLOS), and protracted LOS (LOS > 30).

METHODS

Patients ≥18 years old who underwent neurosurgical procedures between 2012 and 2020 were queried from the ACS-NSQIP. We performed receiver operating characteristic analysis, and multivariable analyses to examine discriminatory thresholds and identify independent associations.

RESULTS

There were 411,605 patients included, with a median age of 59 years (IQR, 48-69), 52.2% male patients, and a white majority 75.2%. For eLOS: RAI C-statistic 0.653 (95% CI: 0.652-0.655), versus mFI-5 C-statistic 0.552 (95% CI: 0.550-0.554) and increasing patient age C-statistic 0.573 (95% CI: 0.571-0.575). Similar trends were observed for pLOS- RAI: 0.718, mFI-5: 0.568, increasing patient age: 0.559, and for LOS>30- RAI: 0.714, mFI-5: 0.548, and increasing patient age: 0.506. Patients with major complications had eLOS 10.1%, pLOS 26.5%, and LOS >30 45.5%. RAI showed a larger effect for all three outcomes, and major complications in multivariable analyses.

CONCLUSION

Increasing frailty was associated with three key quality metrics that is, eLOS, pLOS, LOS > 30 after neurosurgical procedures. The RAI demonstrated a higher discriminating threshold compared to both mFI-5 and increasing patient age. Preoperative frailty screening may improve quality metrics through risk mitigation strategies and better preoperative communication with patients and their families.