Patrick Culligan, MD, FACOG, FACS
Atlantic Health System
Morristown, New Jersey
Siddiqui NY, Amundsen CL, Visco AG, Myers ER, Wu JM. Cost-effectiveness of sacral neuromodulation versus intravesical botulinum A toxin for treatment of refractory urge incontinence. J Urol. 2009;182:2799-2804.
Sacral neuromodulation has emerged as a viable yet very expensive treatment option for patients with refractory urinary frequency, urge incontinence, and non-obstructive voiding dysfunction. Recently botulinum toxin A was approved by the FDA for refractory overactive bladder (patients with symptoms of urge urinary incontinence, urgency, and frequency, who have an inadequate response to, or are intolerant of an anticholinergic medication) and is also approved for neurogenic bladder. This study used a decision analytic model to determine relative cost-effectiveness of these two treatment options.
- Prospective, non-randomized, multicenter 5 year follow-up study
- A Markov decision model was used to compare the two treatment options over a 2 year theoretical course
- For sacral neuromodulation, the staged implantation scenario was modeled – with assumptions included for proportions of successful and unsuccessful stage 1 and stage 2 procedures
- For the botulinum toxin A arm, the model included office injection of 200 units of intravesical BoNT-A. The model included assumptions regarding need for further injections, complications, etc
- One-way sensitivity analyses were performed using plausible ranges of the various point estimates. These point estimates were derived from the best available literature
- Costs were estimated using the societal perspective and a macro-costing approach
- Estimates for the quality of life associated with the various outcomes within the model were derived from the medical literature and discounted over time
- The primary outcome was the incremental cost-effectiveness ratio, which is determined by the following calculation: (sacral nerve stimulation cost – botulinum toxin A cost)/(sacral nerve stimulation quality adjusted life-year – botulinum toxin A quality adjusted life-year)
- Sacral neuromodulation was more expensive than botulinum toxin A injection ($15,743 versus $4,392), but also more effective (1.73 versus 1.63 quality adjusted life years, respectively)
- Over the theoretical 2-year period modeled, the incremental cost-effectiveness ratio was $116,427 per quality adjusted life year. Therefore, botulinum toxin A was the more cost-effective option
This study represents an excellent example of how to use decision analytic methods to answer important clinical questions. While one can argue that the results of this kind of study are merely a function of the assumptions contained within the model, the use of sensitivity analyses mitigates the impact of any single assumption. The authors did a great job of assessing the quality of life and clinical outcomes (as well as costs) in an objective way. The results are compelling.