Comparative Analysis Between mfi-11 and mfi-5 Frailty Indices in Elective Spine Surgery

Introduction: Frailty is a known predictor of poor outcomes following spine surgery. While both mFI-11 and mFI-5 have been used to assess frailty, no comprehensive analysis has systematically compared their predictive performance across multiple outcomes. The purpose of this study is to conduct a systematic review and meta-analysis to determine which frailty index, mFI-11 or mFI-5, more effectively predicts post-operative outcomes and provides better stratification of patient frailty.

Methods: A systematic literature search was conducted using PubMed, Scopus, and Web of Science databases to identify cohort studies that reported on the association of mFI-11 or mFI-5 with post-operative outcomes in elective spine surgery. Meta-analyses were performed using a random-effects model, with pooled odds ratios (ORs) and p-values were calculated for key outcomes where appropriate, including any adverse event, any medical complication, any surgical complication, mortality, reoperation, and non-routine discharge.

Results: A total of 22 studies were included in the meta-analysis. mFI-11 was associated with increased odds of medical complications (OR 2.09, p=0.0014) and surgical complications (OR 2.03, p=0.0390), but not reoperation (OR 0.95, p=0.8822). These findings were inconsistently significant across sub-analyses comparing higher mFI-11 scores to mFI-11=0. mFI-5 predicted a broader range of outcomes, including any complication (OR 1.7, p< 0.0001), non-routine discharge (OR 3.29, p< 0.0001), and mortality (OR 2.29, p=0.0133). These significant results persisted across sub-analyses comparing higher mFI-5 scores to mFI-5=0. mFI-5 consistently outperformed mFI-11 in predicting post-operative outcomes.

Conclusion : mFI-5 demonstrates greater reliability and consistency in predicting adverse outcomes in elective spine surgery than mFI-11. These findings suggest that mFI-5 may be a better tool for stratifying frailty in surgical patients. Further studies are needed to validate these results and optimize frailty assessment in spine surgery.