Purpose: Our objectives are to (1) identify predictors of treatment success in women with overactive bladder (OAB) after 1 year of percutaneous tibial nerve stimulation (PTNS) maintenance therapy, (2) identify trends in success rates during that 1 year, and (3) assess maintenance treatment adherence.
Materials and methods: A retrospective study of 141 women with OAB was performed with the definition of success based on a Patient Global Impression-Improvement (PGI-I) score of 1 ("very much better") or 2 ("much better") or a PGI-I score of 1, 2, or 3 ("a little better"). Multivariable logistic regression was performed to identify factors associated with treatment response and the Cochrane-Armitage trend test to identify changes in the scores over time.
Results: After completing 12 weekly treatments, 141 women initiated maintenance therapy with a mean treatment interval of 29 days. At 1 year, 75/141 (53.2%) had discontinued treatment. Those adherent with treatment had a sustained treatment response, with 66.2% of women reporting a PGI-I score of 1, 2 and 92.3% reporting a PGI-I score of 1, 2, or 3 at 1 year. Considering those women who discontinued maintenance therapy as treatment failures, the success rate of 1 year of maintenance therapy ranged from 30.7%-42.9%. No clinical factors were found to be predictive of maintenance treatment success or failure.
Conclusions: Although an effective treatment for those adherent, discontinuation rates of PTNS maintenance therapy at 1 year are high. Given the low numbers of women referred to maintenance therapy, and the high discontinuation rates, long-term PTNS treatment may be feasible for only a minority of women with OAB.
Keywords: Maintenance; Neuromodulation; Overactive bladder; Therapeutics; Tibial nerve; Treatment.