In-Hospital Mortality After Lumbar Fusion is Rare But Occurs Early: A Nationwide Analysis of Risk Factors, 2016-2022

Study Design Retrospective cohort study. Objectives To update national estimates of in-hospital mortality after lumbar fusion, characterize when deaths occur during hospitalization, and identify independent predictors of mortality. Methods Adult (≥18 years) lumbar fusion hospitalizations in the National Inpatient Sample (NIS) from 2016 to 2022 were analyzed. The primary outcome was in-hospital mortality. Secondary outcomes included hospital-day timing of death and survivor–decedent comparisons of comorbidity and perioperative complication profiles. Multivariable logistic regression identified independent predictors ( P 90% by ∼ 30 days). Decedents more often underwent multilevel fusion (67.8% vs 38.8%, P < 0.001), were aged ≥75 years (41.5% vs 16.5%, P < 0.001), and had higher comorbidity burden (mean Elixhauser count 3.92 vs 2.15, P < 0.001). Independent predictors included age ≥75 years (OR 4.49, P = 0.003), multilevel fusion (OR 2.09, P < 0.001), congestive heart failure (OR 4.46, P < 0.001), coagulopathy (OR 3.44, P < 0.001), neurologic disorders (OR 9.27, P < 0.001), peripheral vascular disease (OR 1.61, P = 0.031), and higher comorbidity count (per-point OR 1.16, P = 0.010). Female sex (OR 0.72, P = 0.022) and highest income quartile (OR 0.58, P = 0.009) were protective. Conclusions In-hospital mortality after lumbar fusion is uncommon but concentrates early and disproportionately affects older, medically complex patients undergoing multilevel procedures, supporting preoperative counseling, front-loaded perioperative risk stratification, and heightened early postoperative vigilance.