Metabolic Syndrome has a Negative Impact on Cost Utility Following Spine Surgery

Abstract

Objective: Investigate the differences in spine surgery cost for metabolic syndrome patients.

Methods: Included were patients ≥18 undergoing fusion. Patients were divided into cervical, thoracic, and lumbar groups based on their upper instrumented vertebrae (UIV). Metabolic syndrome patients (MetS) included those with body mass index >30, diabetes mellitus, dyslipidemia, and hypertension. Propensity score matching for invasiveness between non-MetS and MetS used to assess cost differences. Total surgery costs for MetS and non-MetS adult spinal deformity patients were compared. Quality-adjusted life years (QALYs) and cost per QALY for UIV groups were calculated.

Results: A total of 312 invasiveness matched surgeries met inclusion criteria. Baseline demographics and surgical details included age 57.7 ± 14.5, 54% female, body mass index 31.1 ± 6.6, 17% anterior approach, 70% posterior approach, 13% combined approach, and 3.8 ± 4.1 levels fused. The average costs of surgery between MetS and non-Mets patients was $60,579.30 versus $52,053.23 (P < 0.05). When costs were compared between UIV groups, MetS patients had higher cervical and thoracic surgery costs ($23,203.43 vs. $19,153.43, $75,230.05 vs. $65,746.16, all P < 0.05) and lower lumbar costs ($31,775.64 vs. $42,643.37, P < 0.05). However, the average cost per QALY at 1 year was $639,069.32 for MetS patients and $425,840.30 for non-Mets patients (P < 0.05). At life expectancy, the cost per QALY was $45,456.83 versus $26,026.84 (P < 0.05).

Conclusions: When matched by invasiveness, MetS patients had an average 16.4% higher surgery costs, 50% higher costs per QALY at 1 year, and 75% higher cost per QALY at life expectancy. Further research is needed on the possible utility of reducing comorbidities in preoperative patients.

Keywords: Cervical fusion; Costs per QALY; Lumbar fusion; Metabolic syndrome; Obesity; Quality adjusted life years; Spine surgery.