Acupuncture for the Treatment of Diarrhea-Predominant Irritable Bowel Syndrome: A Pilot Randomized Clinical Trial

This multicenter randomized pilot study represents an important milestone in acupuncture research for diarrhea-predominant irritable bowel syndrome (IBS-D), being the first to use composite endpoints recommended by the U.S. Food and Drug Administration (FDA) as the primary outcome. Irritable bowel syndrome affects 5-10% of the world's population and causes a significant impact on patients' quality of life, often greater than diabetes or end-stage renal disease. The study was conducted at 4 tertiary hospitals in China between July 2020 and March 2021, rigorously following Rome IV criteria for IBS-D diagnosis.

The methodology included a crucial 2-week screening period to adequately identify eligible patients, followed by 4 weeks of treatment and 8 weeks of follow-up. The 90 participants were randomized into three groups: specific acupoints (SA), nonspecific acupoints (NSA), and non-acupoints as sham control (NA), each with 30 patients. Treatment consisted of 12 sessions of 30 minutes over 4 consecutive weeks, performed by certified acupuncturists with at least 3 years of experience. The primary endpoint was innovative in adopting FDA composite criteria, defining response as at least a 30% reduction in abdominal pain and a 50% or greater reduction in days with type 6 or 7 stools on the Bristol Stool Scale.

The results showed identical composite response rates in the SA and NSA groups (46.7%) compared with the NA control group (26.7%), although without statistical significance (P=0.18). Interestingly, adequate relief measures showed a favorable trend toward the active acupuncture groups, with the SA group reaching 64.3% response at week 4, maintained during follow-up. Safety was excellent, with only mild and transient adverse events, including minor hematomas and post-needling residual sensations. The study demonstrated important technical feasibility: a recruitment rate of 55.2%, a low dropout rate (12.2%), and high adherence to treatment (91.1% completed the sessions).

Blinding was effective, with innovative use of blunted needles that do not penetrate the skin in the control group. Limitations include the small sample size, resulting in insufficient statistical power to detect clinically significant differences, and only 12 treatment sessions, which may have been insufficient to demonstrate robust effects. The study suggests that higher doses of acupuncture (16-18 sessions) and more frequent manipulation to obtain deqi could optimize results. All groups showed continued improvement during the follow-up period, suggesting late effects of acupuncture or self-healing processes.

The 20% difference between active acupuncture and sham may represent a clinically meaningful benefit in real clinical practice. This work establishes a solid methodological basis for larger future studies and validates the use of FDA endpoints for acupuncture research in IBS-D, potentially reducing the high placebo response rates traditionally observed in IBS studies.