Estimating the cost-effectiveness of onabotulinumtoxinA for neurogenic detrusor overactivity in the United States.

BACKGROUND

Urinary incontinence (UI) secondary to a neurogenic pathology, including spinal cord injury and multiple sclerosis, is termed neurogenic detrusor overactivity (NDO). Patients with NDO experience decreased quality of life and are at risk for upper urinary tract damage. Two recent trials demonstrated that onabotulinumtoxinA significantly reduced UI, improved urodynamic parameters, and improved quality of life relative to placebo. However, the economic impact of onabotulinumtoxinA treatment for UI due to NDO in the United States remains unknown.

OBJECTIVE

The objective of this analysis was to evaluate whether the benefit observed in NDO patients receiving onabotulinumtoxinA provides good value for money.

METHODS

We developed a Markov state transition model to estimate population outcomes and costs for anticholinergic-refractory NDO patients who received either onabotulinumtoxinA or best supportive care (use of incontinence pads with either an anticholinergic drug, clean intermittent self-catheterization, or both). Nonresponding patients (<50% reduction in UI episodes at 6 weeks) were eligible to receive invasive procedures, including augmentation cystoplasty or sacral neuromodulation. Patients could transition through 6 health states, 3 defined based on response to initial treatment, 2 capturing patients who underwent invasive procedures, and death. Time in each health state was adjusted for patient quality of life and summed to estimate quality-adjusted life-years (QALYs). The model included direct medical costs related to initial and subsequent drug and invasive treatments, physician visits, and catheterization. Outcomes and costs were summed and compared across intervention groups by using the incremental cost-effectiveness ratio (ICER; cost per QALY). The time horizon of the model was 3 years, and results were discounted at 3%. Scenario, 1-way, and probabilistic sensitivity analyses were performed to test the robustness of the model results.

RESULTS

In the base case, onabotulinumtoxinA increased QALYs by 0.059 and costs by $1466 compared with best supportive care, which resulted in an estimated ICER of $24,720/QALY. OnabotulinumtoxinA also decreased mean UI episodes per person-year by 398, resulting in a cost of $4 per UI episode avoided. Model results were most sensitive to the probability of treatment response. The probabilistic sensitivity analysis indicated that at a willingness to pay of $50,000/QALY, onabotulinumtoxinA has a 97% probability of being cost-effective. In subgroup analyses of each etiology, onabotulinumtoxinA yielded an ICER of $32,268/QALY in multiple sclerosis and $2182 in spinal cord injury.

CONCLUSION

OnabotulinumtoxinA seems to be a cost-effective intervention for UI due to NDO compared with best supportive care.