Impacts of low BMI on fusion surgery for osteoporotic vertebral compression fracture: A National Readmission Database Analysis, 2016-2020.

Objective: Osteoporotic vertebral compression fractures (OVCFs) occur commonly among older adults and may require spinal fusion when instability or neurological compromise is present. Low body mass index (BMI), representing body weight relative to height, is often associated with frailty and undernutrition and may increase vulnerability to adverse surgical outcomes, but the influence of low BMI on OVCF fusion surgery remains unclear. This study aimed to evaluate associations between low BMI and short-term outcomes following spinal fusion for OVCFs in older adults.

Methods: This retrospective cohort study analyzed data of older adults (≥50 years) undergoing spinal fusion for OVCF extracted from the US National Readmissions Database (NRD),2016-2020. Overweight or obese patients or those with malignancy were excluded. After 1:4 propensity score matching (PSM), multivariable regression models were used to assess outcomes.

Results: The final matched cohort included 590 patients (118 low BMI, 472 normal BMI). Low BMI was significantly associated with 30- and 90-day readmission (OR = 2.66, 95% CI: 1.46-4.83; OR = 2.45, 95% CI: 1.52-3.96), discharge to long-term care (OR = 1.61, 95% CI: 1.09-2.39), longer hospital stays (β = 2.18 days, 95% CI: 0.17-4.19) and any postoperative complication (OR = 2.78, 95% CI: 1.86-4.14). Specific complications with significantly higher risks included dysphagia (OR = 2.42), pneumonia (OR = 2.82), sepsis (OR = 2.82), and blood transfusion (OR = 3.31), whereas a lower risk of wound dehiscence was observed (OR = 0.24).

Conclusion: Low BMI is an independent risk factor for adverse short-term outcomes following spinal fusion for OVCFs, informing perioperative risk assessment and care planning.