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The Five-item Modified Frailty Index is Predictive of 30-day Postoperative Complications in Patients Undergoing Spine
Katherine E Pierce1, Sara Naessig1, Nicholas Kummer1
1Departments of Orthopedic and Neurologic Surgery, NYU Langone Orthopedic Hospital; New York Spine Institute, New York, NY.
Study Design:
Retrospective cohort study.
Objective:
This study aimed to evaluate the utility of the modified frailty index (mFI-5) in a population of patients undergoing spine surgery.
Summary Of Background Data:
The original modified frailty index (mFI-11) published as an American College of Surgeons National Surgical Quality Improvement Program 11-factor index was modified to mFI-5 after variables were removed from recent renditions.
Methods:
Surgical spine patients were isolated using current procedural terminology codes. mFI-11 (11) and mFI-5 (5) were calculated from 2005 to 2012. mFI was determined by dividing the factors present by available factors. To assess correlation, Spearman rho was used. Predictive values of indices were generated by binary logistic regression. Patients were stratified into groups by mFI-5: not frail (NF, <0.3), mildly frail (MF, 0.3-0.5), severely frail (SF, >0.5). Means comparison tests analyzed frailty and clinical outcomes.
Results:
After calculating the mFI-5 and the mFI-11, Spearman rho between the two indices was 0.926(P < 0.001). Each index established significant (all P < 0.001) predictive values for unplanned readmission (11 = odds ratio [OR]: 5.65 [2.92-10.94]; 5 = OR: 3.68 [1.85-2.32]), post-op complications (11 = OR: 8.56 [7.12-10.31]; 5 = OR: 13.32 [10.89-16.29]), and mortality (11 = OR: 41.29 [21.92-77.76]; 5 = OR: 114.82 [54.64-241.28]). Frailty categories by mFI-5 were: 83.2% NF, 15.2% MF, and 1.6% SF. From 2005 to 2016, rates of NF decreased (88.8% to 82.2%, P < 0.001), whereas MF increased (9.2% to 16.2%, P < 0.001), and SF remained constant (2% to 1.6%, P > 0.05). With increase in severity, postoperative rates of morbidities and complications increased.
Conclusion:
The five-factor National Surgical Quality Improvement Program modified frailty index is an effective predictor of postoperative events following spine surgery. Severity of frailty score by the mFI-5 was associated with increased morbidity and mortality. The mFI-5 within a surgical spine population can reliably predict post-op complications. This tool is less cumbersome than mFI-11 and relies on readily accessible variables at the time of surgical decision-making.Level of Evidence: 3.
Insights
The modified frailty index (mFI-5) effectively predicts postoperative complications and mortality in spine surgery patients. This simpler index is a valuable tool for assessing surgical risk.
Area of Science:
- Spine Surgery Outcomes
- Surgical Risk Assessment
- Frailty Indices
Background:
- The modified frailty index (mFI-11) was previously developed from the American College of Surgeons National Surgical Quality Improvement Program.
- The mFI-5 is a modified version of the mFI-11, with fewer variables.
- Frailty assessment is crucial for predicting surgical outcomes.
Purpose of the Study:
- To evaluate the clinical utility of the modified frailty index with five factors (mFI-5) in patients undergoing spine surgery.
- To compare the predictive performance of mFI-5 against the mFI-11.
Main Methods:
- A retrospective cohort study design was employed.
- Patients undergoing spine surgery were identified using Current Procedural Terminology codes.
- The mFI-11 and mFI-5 were calculated, and their correlation and predictive values for adverse outcomes were assessed using Spearman rho and binary logistic regression, respectively.
Main Results:
- A strong correlation (Spearman rho = 0.926) was found between mFI-5 and mFI-11.
- Both indices significantly predicted unplanned readmission, postoperative complications, and mortality.
- Increasing mFI-5 scores correlated with higher rates of morbidity and mortality.
Conclusions:
- The mFI-5 is an effective and less cumbersome tool for predicting postoperative events in spine surgery.
- Frailty severity, as measured by mFI-5, is associated with increased morbidity and mortality.
- mFI-5 provides reliable prediction of post-operative complications using readily accessible variables.
