Study examines real-world effectiveness of percutaneous tibial nerve stimulation for treating overactive bladder.
Montreal-Percutaneous tibial nerve stimulation (PTNS) is more effective when used adjunctively with pharmacotherapy for a 3-month period to treat overactive bladder (OAB), according to retrospective data presented at the International Continence Society annual meeting in Montreal.
"In clinical trial settings, the rate of effectiveness of PTNS is 60% to 70%, but there is a paucity of real-world effectiveness data, and the drop-out rate has not been reported," explained presenting author Yahir Santiago-Lastra, MD, of the University of Michigan Health System, Ann Arbor. "Our objectives were to determine the effectiveness of PTNS for refractory OAB in an independent clinical setting, report patient adherence to the recommended 12 weeks of therapy, and identify subsequent treatments offered to patients who did not improve during that period (of PTNS treatment)."
Dr. Santiago-Lastra and colleagues used procedural terminology codes to identify patients who had undergone weekly PTNS treatment using the Urgent PC Neuromodulation system (Cogentix Medical, Minnetonka, MN). Treatments lasted 30 minutes per session for a 12-week period. Patient symptoms had been evaluated with the AUA Symptom Index and the Michigan Incontinence Symptom Index. Investigators defined success with PTNS by a transition from weekly treatment to monthly maintenance therapy.
A total of 75 patients with a mean age of 66.8 years, 53 of whom were women, entered 12 weeks of treatment. The vast majority had tried previous therapies, including pharmacologic therapy, botulinum toxin (Botox), neuromodulation, and pelvic floor physical therapy. Patients who had entered the study had trialed a mean of 1.7 OAB medications at baseline, Dr. Santiago-Lastra noted.
"Most patients who undergo PTNS have not responded well to first-line treatments for OAB," said Dr. Santiago-Lastra, who worked on the study with Anne Pelletier Cameron, MD, and colleagues.
One of the advantages of PTNS is that it has a favorable side effect profile, said Dr. Santiago-Lastra. In the study, two patients experienced either ankle pain or ankle edema during needle placement, which terminated the treatment.
"Botulinum toxin and (sacral) neuromodulation are more invasive treatments. Some of these patients may have comorbidities which preclude them from being surgical candidates (for sacral neuromodulation),” she said.
Forty-six patients completed the treatment. Loss to follow-up, no improvement, the presence of comorbidities, and a loss of insurance were reasons why patients did not complete 12 weeks of therapy. A total of 25 patients (33%) successfully transitioned to monthly maintenance therapy. The 21 patients who completed 12 weeks of PTNS but did not transition to monthly maintenance reported insufficient symptom improvement and looked to other therapies after PTNS treatment, including botulinum toxin, sacral neuromodulation, pharmacotherapy, and pelvic floor physical therapy.
A total of 25 of the 75 patients undergoing PTNS treatment were on adjunctive pharmacologic therapy, and those patients were more successful with PTNS, transitioning to monthly treatments, noted Dr. Santiago-Lastra.
"Adjunctive pharmacotherapy has been associated with a statistically significant difference (p<.002) in transitioning to monthly maintenance therapy," Dr. Santiago-Lastra said. "We don't know if PTNS is more successful with medication or the response was better to medication with PTNS. We need to explore the association between medication use and PTNS further."
Of the 25 patients who did transition to monthly treatments, the mean duration of monthly treatment was 8 months. Those who did not continue ongoing monthly maintenance looked to other therapies, including botulinum toxin, sacral neuromodulation, or the beta-3 agonist mirabegron (Myrbetriq).
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