Does Age Younger Than 65 Affect Clinical Outcomes in Medicare Patients Undergoing Lumbar Fusion?

Study Design: This was a retrospective cohort study. Objective: To determine if age (younger than 65) and Medicare status affect patient outcomes following lumbar fusion. Summary of Background Data: Medicare is a common spine surgery insurance provider, but most qualifying patients are older than age 65. There is a paucity of literature investigating clinical outcomes for Medicare patients under the age of 65. Materials and Methods: Patients 40 years and older who underwent lumbar fusion surgery between 2014 and 2019 were queried from electronic medical records. Patients with >2 levels fused, >3 levels decompressed, incomplete patient-reported outcome measures (PROMs), revision procedures, and tumor/infection diagnosis were excluded. Patients were placed into 4 groups based on Medicare status and age: no Medicare under 65 years (NM<65), no Medicare 65 years or older (NM≥65), yes Medicare under 65 (YM<65), and yes Medicare 65 years or older (YM≥65). T tests and χ²tests analyzed univariate comparisons depending on continuous or categorical type. Multivariate regression for ΔPROMs controlled for confounders. Alpha was set at 0.05. Results: Of the 1097 patients, 567 were NM<65 (51.7%), 133 were NM≥65 (12.1%), 42 were YM<65 (3.8%), and 355 were YM≥65 (32.4%). The YM<65 group had significantly worse preoperative Visual Analog Scale back (P=0.01) and preoperative and postoperative Oswestry Disability Index (ODI), Short-Form 12 Mental Component Score (MCS-12), and Physical Component Score (PCS-12). However, on regression analysis, there were no significant differences in ΔPROMs for YM <65 compared with YM≥65, and NM<65. NM<65 (compared with YM<65) was an independent predictor of decreased improvement in ΔODI following surgery (β=12.61, P=0.007); however, overall the ODI was still lower in the NM<65 compared with the YM<65. Conclusion: Medicare patients younger than 65 years undergoing lumbar fusion had significantly worse preoperative and postoperative PROMs. The perioperative improvement in outcomes was similar between groups with the exception of ΔODI, which demonstrated greater improvement in Medicare patients younger than 65 compared with non-Medicare patients younger than 65. Level of evidence: Level III (treatment).