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

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.

Introduction

Metabolic syndrome (MetS) refers to a combination of medical disorders that increase the risk for multiple disease processes, including cardiovascular morbidity and mortality.1, 2, 3 Although there is no exact definition, the presence of obesity, hypertension, dyslipidemia, and diabetes are consensus components of the disease complex.4, 5, 6 There has been a rise in the prevalence of the MetS, with an estimated 25% to 33% of adults meeting criteria.⁷ In addition, MetS is a significant burden among older patients, as an analysis of US data from the cohort of the Framingham Offspring Study showed that the prevalence of MetS increased by approximately 50% from baseline at 50 years old, going from 21% to 34% in men and from 12.5% to 24% in women at 8 years of follow-up.⁸

MetS has been shown to negatively affect perioperative outcomes in spine surgery. In particular, MetS is associated with increased complications, readmissions, and length of stay compared to non-MetS patients.^2,9 Because both the prevalence of spine surgery and MetS increase in parallel, there is a concern that outcomes may be compromised and expenditures increase among individuals with MetS. With increased pressure of pricing and cost transparency, improving the segmentation of cost analysis in spine surgery becomes crucial.

In this context, we sought to evaluate the total cost of surgery and cost per quality adjusted life years (QALYs) for spine fusion surgery patients. We hypothesized that MetS would be associated with more costly care and reduced cost-efficiency overall. Gaining a better understanding of the costs associated with MetS in spine surgery will allow for determination of cost-effectiveness of treating this population. Because the diseases encompassing MetS are objective and modifiable, these results contribute to the increasingly paramount discussion on cost efficiency and the potential utility of preoperative optimization. Therefore, with this shifting health care landscape, analyzing the costs associated with MetS in spine surgery can allow for improvements in surgical care.