Percutaneous tibial nerve stimulation (PTNS) is a minimally invasive therapy for the treatment of overactive bladder (OAB). PTNS has a favorable risk profile, making it an attractive option for older adults who may be particularly vulnerable to adverse events related to pharmacotherapy, such as cognitive side effects associated with anticholinergic OAB medications. While the recommended induction PTNS schedule of 12 sessions in 12 weeks is informed by clinical trial data, real-world utilization may vary, highlighting the challenges potentially posed by the recommended schedule. The purpose of this study was to develop a definition of induction PTNS among Medicare beneficiaries based on real-world utilization.

This is a retrospective cohort study of a 100% sample of fee-for-service Medicare beneficiaries undergoing PTNS treatment for OAB from 2015-2021. Induction cases were identified in the Medicare Carrier files by the presence of CPT-4 codes for PTNS in the absence of any PTNS codes in the prior year.  Procedures with a corresponding diagnostic code for neurogenic bladder were excluded.  Histograms and descriptive characteristics for induction PTNS use were compared for various time intervals, and sensitivity analyses were conducted to arrive at the most optimal definition of induction PTNS treatment. Comparisons were made between the cohort-defined schedule of induction PTNS and the standard schedule for PTNS (12 treatments in 12 weeks). An adjusted multivariable modified Poisson regression was created to determine factors associated with the completion of the cohort-based definition of induction PTNS.

A total of 41,962 unique beneficiaries underwent at least one PTNS treatment during the study period. The average number of PTNS sessions completed within one year of follow-up was 11, with 55.1% of beneficiaries achieving this number of treatments. Based on an evaluation of the distribution of PTNS sessions at varying time intervals, the optimal schedule for induction PTNS in Medicare beneficiaries was determined to be 11 PTNS treatments in 15 weeks (Figure 1). Thirty-three percent of beneficiaries completed the cohort-defined schedule of induction PTNS (11 treatments in 15 weeks) compared to only 8% of beneficiaries who adhered to the standard schedule (12 treatments in 12 weeks). The proportion of beneficiaries continuing PTNS after induction PTNS differed slightly between the two cohorts—64.3% who followed the cohort-defined PTNS schedule and 71.3% who completed the standard schedule continued PTNS. Beneficiaries who completed the cohort-defined induction PTNS schedule were less likely to be older (aRR 0.91, 95%CI 0.87-0.96 vs age 65-74),non-white (aRR 0.88, 95% CI 0.84-0.93 vs white race), severely comorbid (aRR 0.78, 95% CI 0.75-0.81 vs no comorbidities) and mildly to severely frail (aRR 0.83, 95% CI 0.79-0.87 vs non-frail).

Real-world data for utilization of PTNS for nonneurogenic OAB treatment was used to determine a realistic schedule for induction PTNS of 11 sessions in 15 weeks in Medicare beneficiaries. The cohort-defined schedule outperformed the standard schedule of PTNS and was completed by three times as many beneficiaries as the standard schedule. Despite being a less stringent schedule, beneficiaries who completed the cohort-defined schedule continued PTNS at comparable rates to beneficiaries who completed the standard schedule.

These results suggest that the cohort-defined schedule of 11 PTNS treatments in 15 weeks was a more realistic and potentially useful schedule for induction PTNS that can be used for future research on PTNS utilization in older adults.