Modifiable Uncontrolled Frailty (mFI-5) in Lumbar Fusion Outcomes

STUDY DESIGN: Retrospective Cohort. OBJECTIVE: To investigate impact of controlled/uncontrolled sub-stratification of modified frailty index (MFI-5) on postoperative outcomes after lumbar fusion for degenerative disease. BACKGROUND: mFI-5 outperforms age as a predictor of postoperative risk. Sub-stratification of mFI-5 by controlled versus uncontrolled frailty has allowed for better risk prognostication in spinal deformity cases. METHODS: Adult patients who underwent elective, single-level lumbar fusion (2017-2021) were identified. Fusions for infection/trauma/tumor/revision were excluded. Patients were classified as frail/non-frail based on having any mFI-5 criteria (history of chronic obstructive pulmonary disease [COPD], congestive heart failure [CHF], diabetes mellitus [DM], hypertension [HTN] requiring medication, and functional status). Frailty was considered controlled unless patients had a COPD exacerbation within 3 months prior to surgery, preoperative hemoglobin A1c >7, or HTN ≥140/90 mmHg for ≥2 visits. RESULTS: 1,286 patients were included (controlled/uncontrolled/non-frail-804/159/323). Uncontrolled frailty patients had more 31-90 day ED visits (9.43% vs. 4.13%,P=0.009), 0-30 day readmissions (5.66% vs. 2.49%,P=0.042), and renal complications (13.2% vs. 6.38%,P=0.005) compared to controlled frailty patients. Controlled frailty patients were older (56.3 vs. 62.9, P