SUmiT: Percutaneous Tibial Nerve Stimulation Versus Sham for Overactive Bladder
SUmiT was a multicenter, double-blind, sham-controlled randomized trial in 220 adults with overactive bladder symptoms after failed conservative care that compared 12 weekly sessions of percutaneous tibial nerve stimulation (PTNS) with the Urgent PC device against sham stimulation. At week 13, 54.5% of the PTNS group and 20.9% of the sham group reported moderate or marked improvement in overall bladder symptoms (P < 0.001).[1]
- Design and population
- Multicenter, double-blind, sham-controlled superiority randomized trial. 220 adults (174 women, 46 men) at 23 US centers with overactive bladder symptoms, more than 10 voids per 24 hours and failed conservative care, off antimuscarinics for at least 2 weeks.
- Arms
- Percutaneous tibial nerve stimulation (Urgent PC), 12 weekly 30-minute sessions versus sham stimulation, 12 weekly 30-minute sessions
- Report and follow-up
- 2010 · 13 weeks (after 12 weekly sessions)
| Endpoint | Results | Effect | Finding |
|---|---|---|---|
| Moderately or markedly improved on the 7-level global response assessment at week 13, intention to treat; difference in proportions, PTNS minus sham (derived) | 54.5% (60/110) vs 20.9% (23/110) | difference 33.6; P <0.001 | Met |
Harms: Serious device-related adverse events or device malfunctions: none reported vs none reported; Serious adverse events: 0/110 vs 0/110; Participants with a non-serious adverse event: 6/110 (5.5%) vs 0/110
Design
The trial ran at 23 US urology and urogynecology centers and was sponsored by Uroplasty, the manufacturer of Urgent PC. Registry dates run from September 2008 to a primary completion date of June 2009.[2][3] Eligible adults had an OAB-q short-form urgency item score above 4, average frequency above 10 voids per 24 hours on a 3-day diary, symptoms for more than 3 months, failed conservative care and no antimuscarinic for at least 2 weeks. Exclusions included neurogenic bladder, a primary complaint of stress incontinence, current urinary or vaginal infection, prior PTNS, current InterStim or TENS use, and a pacemaker or implantable defibrillator. Investigators could also exclude on history or examination, including bleeding disorders, anticoagulant use and peripheral neuropathy.[2]
The 220 participants (174 women, 46 men) were randomized 1:1, 110 per arm. The prespecified primary endpoint was the proportion reporting a moderately or markedly improved response for overall bladder symptoms on a 7-level global response assessment at week 13, analyzed by intention to treat. The sample size of 214 (107 per arm) assumed responder rates of 60% with PTNS and 40% with sham, with a two-sided alpha of 5% and 80% power.[1] Diary parameters and OAB-q questionnaires were also evaluated.[1][2][3] Mean age was 62.5 years with PTNS and 60.2 years with sham; 56 PTNS and 46 sham participants were 65 or older.[2]
Results
In the intention-to-treat analysis, 60/110 (54.5%) PTNS participants and 23/110 (20.9%) sham participants were moderately or markedly improved at week 13, a difference of 33.6 percentage points (P < 0.001), which met the primary hypothesis.[1] Among participants who completed the week-13 assessment, the proportions were 60/103 (58.3%) and 23/105 (21.9%).[1][2][3]
On 3-day diaries after 12 sessions, mean intentional voids per day fell from 12.3 to 9.8 with PTNS and from 12.4 to 11.0 with sham (P = 0.01); nighttime voids fell from 2.9 to 2.1 versus 2.9 to 2.6 (P = 0.04). Median moderate-to-severe urgency episodes per day fell from 8.3 to 3.7 versus 8.0 to 5.0 (P < 0.001), and median urge incontinence episodes per day from 3.0 to 0.3 versus 1.8 to 1.0 (P = 0.002). The sham group began with the lower median urge incontinence count.[3] Among completers, global response for frequency was 49/103 (47.6%) versus 23/105 (21.9%; P < 0.001), for urgency 44/103 (42.7%) versus 22.9% (P = 0.003), and for urge incontinence 39/103 (37.9%) versus 23/104 (22.1%; P = 0.02).[3]
After 6 sessions (week 7), the overall global response was 28/105 (26.7%) with PTNS and 17/107 (15.9%) with sham (P = 0.07); the investigators concluded that 12 weekly sessions are needed. Efficacy did not differ between participants younger than 65 and those 65 or older, and sexual function indices did not change significantly in either arm.[3]
The STEP study followed 50 SUmiT participants who met the primary end point after 12 weekly sessions. After a 14-week taper, they continued under a personal treatment plan. At 24 months, 35 of 50 remained; among 45 participants treated after taper, the mean treatment frequency from months 6 to 24 was 1.3 per month, and diary frequency, urge incontinence, nighttime voids and urgency episodes were significantly improved from baseline at each 6-month assessment.[4] At 3 years, 29 of 50 had completed the protocol; among 45 participants treated after taper, the median was 1.1 treatments per month from months 6 to 36 (1.0 among the 29 completers).[5] A Bayesian model that accounted for early withdrawal estimated that 77% (95% CI 64–90) maintained moderate or marked improvement.[5] Median voids per day fell from 12.0 to 8.7, nighttime voids from 2.7 to 1.7 and urge incontinence episodes per day from 3.3 to 0.3 (all P < 0.0001).[5]
Surgery and treatment delivery
PTNS used the Urgent PC device with a 34-gauge needle electrode inserted near the posterior tibial nerve and an active surface electrode, in 30-minute sessions once a week for 12 weeks.[3] The AUA/SUFU guideline summarizes the SUmiT protocol as a current of 0.5 to 9 mA at 20 Hz.[6]
The sham reproduced the sensation and setup without tibial nerve activation. A Streitberger placebo needle gave the sensation of a needle without piercing the skin, TENS pads above and below the small toe gave the sensation of stimulation, an inactive surface electrode was placed, and the device sounds were reproduced.[3] Of the 110 randomized to each arm, 103 PTNS and 105 sham participants completed the study; the 7 and 5 who did not remained in the intention-to-treat denominator.[2]
Adverse events
No serious device-related adverse events or device malfunctions were reported.[1] The registry lists no serious adverse events in either arm and non-serious events in 6/110 (5.5%) PTNS participants versus 0/110 sham participants: bleeding at the needle site in 3, discomfort at the needle site in 2, ankle bruising in 1 and tingling in the leg in 1 (7 term counts in 6 participants).[2] In STEP, 5 mild adverse events of unknown relation to treatment were reported through 24 months, and one patient had 2 mild treatment-related episodes of needle-site bleeding through 3 years.[4][5]
Limitations
The primary endpoint was a patient-reported global response, and the controlled comparison ended at week 13. Durability comes from STEP, which was uncontrolled, included only the 50 initial responders and retained 29 at 3 years. The manufacturer sponsored the trial.[2][3][5] The arms differed at baseline in age distribution (56 versus 46 participants aged 65 or older) and in median urge incontinence episodes (3.0 versus 1.8 per day).[2][3] The trial excluded neurogenic bladder, primary stress incontinence and prior PTNS.[2]
In conversation
- Extends OrBIT (2009). Tested the same Urgent PC therapy against sham stimulation rather than against extended-release tolterodine.
- Parallel to OrBIT (2009). Same Urgent PC device and lead investigator; SUmiT compared PTNS with sham stimulation rather than tolterodine.
Same setting OASIS (Revi) (2024)
SUmiT's comparator was sham stimulation, so its 33.6-point difference measures PTNS against the placebo response of a global-improvement endpoint, not against a drug or another third-line therapy. The earlier OrBIT trial compared PTNS with extended-release tolterodine, with similar mean reductions in voids per day (−2.4 versus −2.5) as summarized in the AUA/SUFU guideline.[6]
Guidelines and approvals
- AUA/SUFU (2024). For patients with OAB who have an inadequate response to or intolerable side effects from pharmacotherapy or behavioral therapy, clinicians should offer sacral neuromodulation, tibial nerve stimulation, and/or intradetrusor botulinum toxin injection . The guideline text bases its PTNS protocol on SUmiT and cites its 55% versus 21% improvement.[6]
- EAU female LUTS guideline (2026). Offer posterior tibial nerve stimulation as an option for symptomatic improvement of OAB or urgency urinary incontinence . SUmiT is among the studies cited for PTNS in women with OAB.[7]
Report history
| Published | Report | Cutoff | Headline results | Citation |
|---|---|---|---|---|
| 2010-02-20 | 13-week randomized comparison · primary | — | Moderately or markedly improved on the 7-level global response assessment at week 13, intention to treat; difference in proportions, PTNS minus sham (derived): 54.5% (60/110) vs 20.9% (23/110); difference 33.6; P <0.001 Met 3-day diary after 12 sessions: frequency, nighttime voids, voids with moderate to severe urgency, urge incontinence episodes: Each parameter improved significantly more with PTNS than with sham; magnitudes are in the ICS 2011 abstract report.; — | Peters KM, Carrico DJ, Perez-Marrero RA, et al. "Randomized Trial of Percutaneous Tibial Nerve Stimulation Versus Sham Efficacy in the Treatment of Overactive Bladder Syndrome: Results From the SUmiT Trial." *J Urol.* 2010;183(4):1438-1443. doi:10.1016/j.juro.2009.12.036 DOI |
| 2011-08-31 | ICS 2011 abstract: 6 versus 12 sessions, age strata · abstract | — | Moderately or markedly improved at week 13, participants with a response assessment: 58.3% (60/103) vs 21.9% (23/105); P <0.001 Moderately or markedly improved at week 7 (as followed): 26.7% (28/105) vs 15.9% (17/107); P 0.07 Descriptive Moderately or markedly improved at week 13 (as followed): 47.6% (49/103) vs 21.9% (23/105); P <0.001 Moderately or markedly improved at week 13 (as followed): 42.7% (44/103) vs 22.9%; P 0.003 Moderately or markedly improved at week 13 (as followed): 37.9% (39/103) vs 22.1% (23/104); P 0.02 Mean (SD) at baseline and week 13 after 12 sessions: 12.3 (3.2) to 9.8 (2.8) vs 12.4 (3.0) to 11.0 (3.1); P 0.01 Mean (SD) at baseline and week 13 after 12 sessions: 2.9 (1.6) to 2.1 (1.4) vs 2.9 (1.7) to 2.6 (1.6); P 0.04 Median at baseline and week 13 after 12 sessions: 8.3 to 3.7 vs 8.0 to 5.0; P <0.001 Median at baseline and week 13 after 12 sessions: 3.0 to 0.3 vs 1.8 to 1.0; P 0.002 Global response and OAB-q results stratified by age under 65 versus 65 or older: No significant difference in efficacy by age stratum in either arm; no significant change in sexual function indices (FSFI, SHIM).; — Descriptive | Sand PK, Peters KM, Carrico DJ. "SUmiT Trial Outcomes: Clinical Insights Into Percutaneous Tibial Nerve Stimulation." *International Continence Society 2011 Annual Meeting, Glasgow.* Abstract 28. |
| 2012-06-05 | STEP 24-month results · updated | — | Participants remaining in the study at 24 months: 35/50; — Descriptive Mean treatments per month among 45 participants from study months 6 to 24 after the 14-week taper: 1.3; — Descriptive Change from pre-treatment baseline at 6, 12, 18 and 24 months: Frequency, urge incontinence episodes, nighttime voids and moderate to severe urgency episodes were significantly improved at each time point; OAB-q symptom severity and quality-of-life scores improved at each tested time point.; — Descriptive | Peters KM, Carrico DJ, MacDiarmid SA, et al. "Sustained Therapeutic Effects of Percutaneous Tibial Nerve Stimulation: 24-Month Results of the STEP Study." *Neurourol Urodyn.* 2013;32(1):24-29. doi:10.1002/nau.22266 DOI |
| 2012-12-03 | STEP 3-year results · updated | — | Participants completing the 36-month protocol: 29/50; — Descriptive Bayesian model estimate of the proportion maintaining improvement at 3 years: 77%; CI 64–90 Descriptive Median (IQR), baseline to 3 years: 12.0 (10.3-13.7) to 8.7 (7.3-11.3); P <0.0001 Descriptive Median (IQR), baseline to 3 years: 2.7 (1.7-3.3) to 1.7 (1.0-2.7); P <0.0001 Descriptive Median (IQR), baseline to 3 years: 3.3 (0.7-6.0) to 0.3 (0.0-1.0); P <0.0001 Descriptive | Peters KM, Carrico DJ, Wooldridge LS, et al. "Percutaneous Tibial Nerve Stimulation for the Long-Term Treatment of Overactive Bladder: 3-Year Results of the STEP Study." *J Urol.* 2013;189(6):2194-2201. doi:10.1016/j.juro.2012.11.175 DOI |
References
1. Peters KM, Carrico DJ, Perez-Marrero RA, et al. "Randomized Trial of Percutaneous Tibial Nerve Stimulation Versus Sham Efficacy in the Treatment of Overactive Bladder Syndrome: Results From the SUmiT Trial." J Urol. 2010;183(4):1438-1443. doi:10.1016/j.juro.2009.12.036
2. Uroplasty, Inc. "Study of Urgent PC Versus Sham Effectiveness in Treatment of Overactive Bladder Symptoms (SUmiT)." ClinicalTrials.gov identifier NCT00771264. clinicaltrials.gov
3. Sand PK, Peters KM, Carrico DJ. "SUmiT Trial Outcomes: Clinical Insights Into Percutaneous Tibial Nerve Stimulation." International Continence Society 2011 Annual Meeting, Glasgow. Abstract 28. ics.org
4. Peters KM, Carrico DJ, MacDiarmid SA, et al. "Sustained Therapeutic Effects of Percutaneous Tibial Nerve Stimulation: 24-Month Results of the STEP Study." Neurourol Urodyn. 2013;32(1):24-29. doi:10.1002/nau.22266
5. Peters KM, Carrico DJ, Wooldridge LS, et al. "Percutaneous Tibial Nerve Stimulation for the Long-Term Treatment of Overactive Bladder: 3-Year Results of the STEP Study." J Urol. 2013;189(6):2194-2201. doi:10.1016/j.juro.2012.11.175
6. Cameron AP, Chung DE, Dielubanza EJ, et al. "The AUA/SUFU Guideline on the Diagnosis and Treatment of Idiopathic Overactive Bladder." J Urol. 2024;212(1):11-20. Statement 25. doi:10.1097/JU.0000000000003985
7. European Association of Urology. EAU Guidelines on Management of Non-Neurogenic Female Lower Urinary Tract Symptoms. Limited update March 2026. Sections 4.1.4.a.5.d.1 and 4.1.4.a.5.f.