Seven-year cost-effectiveness of ProDisc-C total disc replacement: results from investigational device exemption and post-approval studies

Abstract

OBJECTIVE The purpose of this study was to evaluate the 7-year cost-effectiveness of cervical total disc replacement (CTDR) versus anterior cervical discectomy and fusion (ACDF) for the treatment of patients with single-level symptomatic degenerative disc disease. A change in the spending trajectory for spine care is to be achieved, in part, through the selection of interventions that have been proven effective yet cost less than other options. This analysis complements and builds upon findings from other cost-effectiveness evaluations of CTDR through the use of long-term, patient-level data from a randomized study. METHODS This was a 7-year health economic evaluation comparing CTDR versus ACDF from the US commercial payer perspective. Prospectively collected health care resource utilization and treatment effects (quality-adjusted life years [QALYs]) were obtained from individual patient-level adverse event reports and SF-36 data, respectively, from the randomized, multicenter ProDisc-C total disc replacement investigational device exemption (IDE) study and post-approval study. Statistical distributions for unit costs were derived from a commercial claims database and applied using Monte Carlo simulation. Patient-level costs and effects were modeled via multivariate probabilistic analysis. Confidence intervals for 7-year costs, effects, and net monetary benefit (NMB) were obtained using the nonparametric percentile method from results of 10,000 bootstrap simulations. The robustness of results was assessed through scenario analysis and within a parametric regression model controlling for baseline variables. RESULTS Seven-year follow-up data were available for more than 70% of the 209 randomized patients. In the base-case analysis, CTDR resulted in mean per-patient cost savings of $12,789 (95% CI $5362-$20,856) and per-patient QALY gains of 0.16 (95% CI -0.073 to 0.39) compared with ACDF over 7 years. CTDR was more effective and less costly in 90.8% of probabilistic simulations. CTDR was cost-effective in 99.8% of sensitivity analysis simulations and generated a mean incremental NMB of $20,679 (95% CI $6053-$35,377) per patient at a willingness-to-pay threshold of $50,000/QALY. CONCLUSIONS Based on this modeling evaluation, CTDR was found to be more effective and less costly over a 7-year time horizon for patients with single-level symptomatic degenerative disc disease. These results are robust across a range of scenarios and perspectives and are intended to support value-based decision making.

Keywords: ACDF = anterior cervical discectomy and fusion; AE = adverse event; CTDR = cervical total disc replacement; FDA = Food and Drug Administration; ICER = incremental cost-effectiveness ratio; IDE = investigational device exemption; NIS = Nationwide Inpatient Sample; NMB = net monetary benefit; QALYs = quality-adjusted life years; RCT = randomized controlled trial; SF-36 = 36-Item Short Form Health Survey; WTP = willingness to pay; anterior cervical discectomy and fusion; cervical total disc replacement; cost-effectiveness; single-level degenerative disc disease.