Impact of frailty on 12-month patient-reported outcomes after posterior lumbar fusion surgery

INTRODUCTION: Frailty might increase the risk for postoperative complications and death. It is not well understood how frailty influences patient-reported outcomes (PROs) in spine surgery. The objective is to investigate on the impact of frailty on PROs 1-year after lumbar fusion. MATERIALS AND METHODS: This was a prospective observational study of patients undergoing open posterior lumbar fusion for degenerative conditions with 12-month follow-up (12 M-FU). The modified 5-item frailty index (mFI-5) score was determined preoperatively. PROs included the Oswestry-Disability-Index (ODI), 12-item Short-Form-Healthy-Survey with Physical (PCS-12) and Mental-Component-Score (MCS-12) and Numerical-Rating-Scale (back/leg pain) before surgery and 6 weeks, 3, 6 and 12 months (6 W, 3 M, 6 M, 12 M) postoperatively. PROs were compared between groups stratified as frail (mFI-5 ≥ 2), pre-frail (mFI-5 = 1) and non-frail (mFI-5 = 0). PRO changes at 12 M-FU were evaluated with substantial clinical benefit (SCB) metrics. Regression models were used to determine associations between mFI-5 and PROs. RESULTS: ) were analyzed. 31.3% and 51.8% of the frail and non-frail patients reached ODI-SCB, respectively. Frailty patients reached a significantly smaller ODI change at 12 M-FU than pre- and non-frail patients (15.2% vs. 19.3% and 19.0%, p < 0.001) Univariate analysis revealed a mFI-5 is significantly associated with ODI (6 W, 3 M and 12 M) and inversely with PCS-12 (3 M, 6 M and 12 M) and MCS-12 (6 W and 3 M). CONCLUSIONS: Frailty patients reached a smaller ODI improvement at 12 M-FU. Frailty might be associated with worse PROs one year after elective lumbar fusion, nevertheless, even frail patients are likely to benefit from an improved quality of life after surgery. The mFI-5 can be assessed preoperatively for risk stratification and used to counsel patients on their expectations for health-related quality of life.