Neither anorectal biofeedback nor dextranomer-hyaluronate injection proved superior for patients with moderate-to-severe fecal incontinence (FI) that had not responded to medical and behavioral therapy, according to a randomized clinical trial published in Clinical Gastroenterology and Hepatology.
At three months, 27.7% of patients who received injections and 29.3% of those who received biofeedback had at least a 75% reduction in FI episodes, a difference that was not statistically significant. Biofeedback cost payers an average of $1,563 less per patient over three months, according to the study.
FI affects approximately 8% of the global population and can substantially reduce quality of life, the authors noted. Guidelines recommend starting with dietary modifications, medication, and pelvic floor exercises, they wrote; for patients who continue to experience symptoms, options include anorectal biofeedback, injectable anal bulking agents, and sacral nerve modulation.
Led by Adil E. Bharucha, MBBS, MD, of the Division of Gastroenterology and Hepatology at Mayo Clinic in Rochester, Minnesota, the Fecal Incontinence Treatment study compared the effectiveness, safety, and costs of biofeedback and dextranomer-hyaluronate injections across five U.S. academic medical centers.
“Fecal incontinence is a heterogeneous disorder ... and patients differ considerably in the severity and pattern of their incontinence, their bowel disturbances, and the underlying anorectal dysfunction,” Dr. Bharucha told GI & Hepatology News. “The two treatments also work quite differently: biofeedback requires active patient engagement and practice, whereas dextranomer injection does not. So going into the trial, I genuinely did not know whether one treatment would prove superior.”
The parallel-group superiority trial enrolled adults with at least four FI episodes over two weeks from March 2019 through November 2023. Participants first completed one month of medical and behavioral therapy involving individualized dietary recommendations, medication adjustments, and pelvic floor exercises. Of the 275 participants who began that therapy, 200 who did not respond adequately were randomly assigned to receive either dextranomer-hyaluronate injections (101 patients) or anorectal biofeedback (99 patients). Women accounted for 88% of this randomized population.
Patients receiving biofeedback underwent five to six sessions over six weeks, incorporating sphincter strengthening, sensory discrimination, and urge-resistance training. The sessions were guided by an FDA-approved manometry device (Medspira) that provides visual feedback. Those assigned to injections received 4 mL of dextranomer-hyaluronate, plus a second injection at six weeks if FI episodes had not fallen by at least 75%. Outcomes were assessed at three and six months; 12- and 24-month data are being analyzed.
The primary efficacy endpoint was a reduction of at least 75% in FI episodes at three months compared with baseline. Dr. Bharucha said “a 75% reduction in fecal incontinence episodes is a stringent endpoint.” He noted that 57.1% of patients in each group who completed bowel diaries had at least a 50% reduction at three months, a threshold commonly used in clinical trials. In the full intention-to-treat population, those figures were 47.5% for injection and 48.5% for biofeedback, according to the study.
Mean improvements in FI frequency at six months, in the Fecal Incontinence Severity Score, and in two Fecal Incontinence Quality of Life subscales (coping and behavior, and embarrassment) were similar to or greater than the minimal clinically important difference. The authors wrote that this indicates the effects were clinically meaningful.
Despite those improvements, fewer than 5% of participants in either group were completely continent at three or six months. Complete continence was defined as no episodes on a two-week bowel diary plus self-reported resolution of symptoms; rates were slightly higher by diary alone, according to the study.
“There is clearly a substantial unmet need,” Dr. Bharucha said. “Fecal incontinence is not a single disease but a final common symptom arising from different combinations of bowel disturbances and anorectal dysfunction. One treatment is therefore unlikely to work for everyone, and these therapies may not fully compensate for dominant problems such as severe bowel disturbances or marked structural or functional anorectal impairment. We need more effective therapies and, just as importantly, better ways to determine which treatment is most appropriate for an individual patient.”
Both treatments were safe, the authors reported. Within three months, 5.6% of injection recipients and 2.2% of biofeedback recipients had an adverse event meeting the trial’s primary safety criteria (grade II or higher pelvic pain, treatment-site infection, or an event requiring hospitalization), a difference that was not statistically significant. Five serious adverse events occurred, none of them treatment-related, according to the study.
However, cost differences between the treatments were more pronounced. Over three months, payer costs averaged $1,734 per patient for injection vs. $171 for biofeedback. From a societal perspective, injections cost $1,579 more per patient. Both differences were statistically significant; the $38 difference in patients’ out-of-pocket costs was not. Costs were calculated in 2024 dollars, based primarily on Medicare reimbursement rates.
The similar observed response rates, safety profiles, and secondary outcomes suggest either treatment may be considered for these patients, the authors wrote. They added that selection should be guided by patient preference, treatment availability, invasiveness, clinician expertise, and cost.
“Perhaps the greatest opportunity is to move toward more individualized treatment, informed by careful characterization of bowel habits and incontinence patterns using bowel diaries,” Dr. Bharucha said. “We need to identify the clinical and physiologic features that predict response to biofeedback, injection, and other therapies, and better understand why a treatment works in one patient but not another.”
Biofeedback costs less and is noninvasive, but most FI therapy in the U.S. is provided by physical therapists who generally do not incorporate biofeedback, the authors wrote. Dr. Bharucha called access to trained therapists “a major challenge, arguably a crisis.”
“In 2020, reimbursement rules changed when the previous biofeedback code was replaced by new time-based codes,” he said. “Under these new rules, anorectal biofeedback can be provided by physicians and certain advanced practice clinicians, or by physical therapists under a therapy plan of care, but trained registered nurses can no longer provide the service under physician supervision, as they had previously done at many centers.”
One solution, Dr. Bharucha said, would be to petition the Centers for Medicare & Medicaid Services to allow trained registered nurses — plus gastroenterology fellows — to once again provide reimbursable biofeedback. Another would be to incorporate anorectal biofeedback into the core curriculum of pelvic floor physical therapy programs.
Asked about the study’s key takeaways, Dr. Bharucha said complete continence “remained uncommon, underscoring the need for more effective and more precisely targeted therapies.”
The authors noted several limitations. The trial had no placebo group, so placebo effects cannot be excluded. Because the treatments differed in delivery, neither patients nor providers were blinded, which may have influenced patient-reported outcomes. The trial was designed to test superiority, so its results should not be read as evidence the treatments are equivalent. Only 12% of randomized participants were men, secondary outcome data were available only for those who completed assessments, and the report covers three- and six-month outcomes only. The sacral nerve modulation arm was also dropped partway through because of poor enrollment.
Dr. Bharucha jointly holds a patent on the Medspira device used to deliver biofeedback in the study, with royalty rights for him and Mayo Clinic, which holds equity in the licensee. Several coauthors reported industry relationships, including with Takeda, Coloplast, Laborie, and Eli Lilly. This study was supported by the National Institute of Diabetes and Digestive and Kidney Diseases grant UO1 DK 115575.