Efficacy of acupuncture for the treatment of Parkinson's disease-related constipation (PDC): A randomized controlled trial

Constipation is one of the most common and debilitating non-motor complications of Parkinson's disease, affecting between 46% and 60% of patients. This condition manifests as reduced bowel movement frequency, hardened stools, prolonged time to evacuate, and sensations of incomplete evacuation and abdominal distension. What makes this situation particularly concerning is that Parkinson's-related constipation can appear years before the characteristic motor symptoms of the disease and tends to worsen as the neurologic condition progresses. Beyond the physical discomfort, this complication significantly interferes with the absorption of antiparkinsonian medications, especially levodopa, compromising motor symptom control and drastically reducing patients' quality of life.

Conventional treatments for constipation in Parkinson's disease include dietary changes with increased fiber and fluids, use of probiotics, and laxative medications. However, these approaches often prove insufficient or cause unpleasant adverse effects such as cramps and bloating when used continuously. Faced with this limitation, many patients and clinicians seek non-pharmacologic alternatives. Acupuncture has emerged as a promising option, as previous studies suggest it may stimulate gastrointestinal motility and improve neurologic symptoms.

However, the specific efficacy of acupuncture for Parkinson's-related constipation had not been adequately investigated through rigorous clinical studies.

This study was conducted as a randomized controlled trial, representing the first high-quality scientific research specifically designed to evaluate the efficacy of acupuncture in treating constipation in patients with Parkinson's disease. The researchers recruited 78 patients between May and November 2022 at the Affiliated Hospital of Guangzhou University of Chinese Medicine. Participants were randomly assigned to two groups: one received real manual acupuncture and the other received sham acupuncture (placebo). The study was carefully designed so that patients, evaluators, and statisticians were unaware of which treatment was being administered, ensuring unbiased results.

The treatments consisted of 12 sessions over 4 weeks, with follow-up for an additional 4 weeks after completion. To create a convincing placebo acupuncture, the researchers developed a special device that maintained the appearance of real acupuncture but without the needles effectively penetrating the skin.

The results clearly and statistically demonstrated that manual acupuncture was superior to sham acupuncture. The primary outcome assessed was the number of complete and spontaneous bowel movements per week. In the group that received real acupuncture, this number increased from 3.36 weekly bowel movements at baseline to 4.62 after treatment, representing a clinically significant gain of 1.26 bowel movements per week. In contrast, the group that received sham acupuncture showed virtually no change, remaining at approximately 3 weekly bowel movements.

The benefits of acupuncture were maintained during the follow-up period, although with some attenuation of intensity. In addition, acupuncture proved effective in improving specific symptoms such as difficulty evacuating, stool consistency, and prolonged time in the bathroom. Constipation-related quality of life also significantly improved in the real acupuncture group, demonstrating that the physical benefits translated into general well-being for patients.

For patients suffering with Parkinson's-related constipation, these results offer a hopeful perspective of safe and effective complementary treatment. Acupuncture may be considered a valuable option, especially for those who do not respond adequately to conventional treatments or experience undesirable adverse effects from laxative medications. For health professionals, the study provides solid scientific evidence to recommend acupuncture as part of an integrated approach in the care of Parkinson's patients. It is important to note that only 6 patients in the real acupuncture group experienced mild and self-limited adverse events, confirming the safety of the procedure.

The treatment did not interfere with antiparkinsonian medications, making it a compatible addition to the existing therapeutic regimen. The observed benefits include not only the increase in the number of bowel movements but also the improvement in bowel movement quality and reduction of associated symptoms such as bloating and the sensation of incomplete evacuation.

Despite the promising results, the study has some important limitations that should be considered when interpreting the findings. The follow-up period was relatively short, preventing assessment of the long-term effects of acupuncture and its influence on the need for antiparkinsonian medications. During follow-up, although the benefits persisted statistically, they did not reach the threshold considered clinically significant, suggesting that Parkinson's-related constipation may be more prone to recurrence than common constipation, possibly requiring maintenance sessions. In addition, the study did not include objective markers that could elucidate the mechanisms by which acupuncture exerts its beneficial effects.

Future studies with longer follow-up periods and investigation of the mechanisms of action will be essential to consolidate the role of acupuncture in the therapeutic arsenal for parkinsonian constipation and to optimize treatment protocols for lasting benefits.