The predictive value of the Fried frailty phenotype in evaluating postoperative outcomes in lumbar spine fusion surgery

OBJECTIVE: The aim of this paper was to validate the Fried frailty phenotype (FFP) in predicting postoperative outcomes in patients undergoing lumbar spine fusion surgery. METHODS: This is a retrospective analysis of the medical records of patients aged 65 years and older who underwent elective lumbar spine surgery between July 2015 and August 2021 at a single institution. The 11-item modified frailty index (mFI-11) and FFP were used to calculate frailty. The Charlson Comorbidity Index (CCI) was used to assess the comorbidity burden. Outcome measures included length of hospital stay (LOS), complication rates, and nonhome discharge. The authors evaluated the correlations among the mFI-11, FFP, and CCI using Spearman correlation testing. After categorizing frailty, they used multivariable regression to determine the relationships between the FFP, mFI-11, CCI, and postoperative outcome measures. RESULTS: A total of 248 patients were included in the analysis. According to the FFP, 23% of patients were frail, and based on the mFI-11, 22% were frail. The FFP and mFI-11 were significantly correlated (rs = 0.20, p = 0.0019). LOS was not found to be significantly correlated with CCI and mFI-11. However, LOS was significantly correlated with the FFP (rs = 0.15, p < 0.0197). The FFP was found to be significantly associated with wound complications, with 44% of those with wound complications identified as frail (p = 0.0339). With regard to nonhome discharge, 52% identified as frail were discharged to a skilled nursing facility, and 31% identified as frail were discharged to inpatient rehabilitation (p = 0.0007). In contrast, the mFI-11 was not found to be significantly related to any complications or nonhome discharge. In the multiple regression model, the FFP was the best independent predictor of nonhome discharge after adjusting for mFI-11 and age. The odds of a nonhome discharge were four times higher for patients classified as frail using the FFP (OR 4.118, 95% CI 2.005-8.458; p = 0.0001). CONCLUSIONS: The FFP strongly predicts nonhome discharge in patients undergoing elective lumbar spine fusion for degenerative spine disease. Frailty as identified using the FFP is significantly correlated with increased LOS, wound complications, and nonhome discharge, while the mFI-11 was not associated with LOS, complications, or nonhome discharge.