The cost effectiveness of surgical versus nonoperative treatment for lumbar disc herniation over two years: evidence from the Spine Patient Outcomes Research Trial (SPORT)

Abstract

Study design: Spine Patient Outcomes Research Trial observational and randomized cohort participants with a confirmed diagnosis of intervertebral disc herniation (IDH) who received either usual nonoperative care and/or standard open discectomy were followed from baseline at 6 weeks, 3, 6, 12, and 24 months at 13 spine clinics in 11 US states.

Objective: To evaluate the cost-effectiveness of surgery relative to nonoperative care among patients with a confirmed diagnosis of lumbar IDH.

Summary of background data: The cost-effectiveness of surgery as a treatment for conditions associated with low back and leg symptoms remains poorly understood.

Methods: Incremental cost-effectiveness ratio, reported as discounted cost per quality adjusted life year (QALY) gained in 2004 US dollars based on EuroQol EQ-5D health state values with US scoring, and information on resource utilization and time away from work.

Results: Among 775 patients who underwent surgery and 416 who were treated nonoperatively, the mean difference in QALYs over 2 years was 0.21 (95% CI: 0.16-0.25) in favor of surgery. Surgery was more costly than nonoperative care; the mean difference in total cost was $14,137(95% CI: $11,737-16,770). The cost per QALY gained for surgery relative to nonoperative care was $69,403 (95% CI: $49,523-94,999) using general adult surgery costs and $34,355 (95% CI: $20,419-52,512) using Medicare population surgery costs.

Conclusion: Surgery for IDH was moderately cost-effective when evaluated over 2 years. The estimated economic value of surgery varied considerably according to the method used for assigning surgical costs.

Figures

Figure 1

Mean health state values and 95% confidence intervals over time by treatment received.

Figure 2

Cost distributions by treatment received over 24 months for A) total costs and B) direct medical non-surgical costs.

Figure 2

Cost distributions by treatment received over 24 months for A) total costs and B) direct medical non-surgical costs.

Figure 3

Mean costs by time period and treatment received. Asterisks show time period differences between treatment groups with p-value

Figure 4

Incremental cost-effectiveness analysis results. A) Results from 1,000 bootstrap estimates of the difference in total costs and difference in QALYs with the mean incremental costeffectiveness ratio shown as a dashed line and the 95% confidence interval shown as solid lines for the General Population and B) Cost-effectiveness acceptability curves for surgery relative to nonoperative care when total costs or direct medical costs alone are considered by population group.

Figure 4

Incremental cost-effectiveness analysis results. A) Results from 1,000 bootstrap estimates of the difference in total costs and difference in QALYs with the mean incremental costeffectiveness ratio shown as a dashed line and the 95% confidence interval shown as solid lines for the General Population and B) Cost-effectiveness acceptability curves for surgery relative to nonoperative care when total costs or direct medical costs alone are considered by population group.