Acupuncture in diabetic peripheral neuropathy-neurological outcomes of the randomized acupuncture in diabetic peripheral neuropathy trial

Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes mellitus, affecting approximately 28% of diabetic patients. This condition manifests through numbness, loss of sensation, burning pain, and tingling in the feet, which can lead to gait instability, falls, and unnoticed injuries due to loss of sensation. Unlike neuropathic pain, for which medications are available, there are no effective pharmacological options to treat numbness and loss of sensation, creating an important therapeutic gap. The ACUDPN study was a multicenter, open-label, randomized controlled clinical trial that investigated the effects of acupuncture on neurological deficits in patients with type 2 DPN.

Conducted in Germany between February 2019 and April 2021, the study included 62 participants with a mean age of 68 years, 79% of whom were men. Inclusion criteria were rigorous, including a confirmed diagnosis of DPN with moderate to severe symptoms and objective evidence of nerve conduction impairment. The acupuncture protocol was standardized, using specific bilateral points: ST-40 and ST-34 (stomach meridian), LR-3 (liver meridian), SP-6 (spleen meridian), KI-3 (kidney meridian), and extra points EX-LE-10 'Bafeng' on the feet. These points were strategically selected for their location close to the fibular and tibial nerves, the main nerves affected in DPN.

The intervention group received 12 acupuncture sessions over 8 weeks, while the control group remained on a waiting list until week 16, when they also received the same treatment. Results were notable in multiple aspects. On the 11-point numerical scale for numbness, the acupuncture group showed an improvement of 2.3 points compared to control at week 8 (p < 0.001), representing a 35.4% reduction in subjective perception of numbness. This effect persisted at week 16 with a difference of 2.2 points (32.4% improvement) and was still present at week 24 with a reduction of 1.8 points compared to baseline.

The Neuropathic Pain Symptom Inventory (NPSI) improved by 12.6 points in the acupuncture group at week 8 (p < 0.001), with persistence of effect at week 16. Neurological examination scores also showed significant improvements. The TNSc (Total Neuropathy Score clinical) improved by 2.0 points at week 8 (p < 0.001) and maintained an improvement of 1.8 points at week 16. The Neuropathy Symptom Score (NSS) showed a difference of 1.3 points favoring acupuncture at week 8 (p < 0.001), persisting at week 16.

The Neuropathy Deficit Score (NDS) also improved by 1.0 point at week 8, with the effect maintained at week 16. Surprisingly, nerve conduction studies performed with the portable NC-stat / DPNCheck device did not show significant changes in sural nerve velocity or amplitude between groups. This discrepancy may be explained by the limitation of the device used, which, although validated for screening, may not have adequate sensitivity to detect changes induced by intervention. The safety of acupuncture was excellent, with only minor adverse effects reported: small local bruises (n=18), transient pain at the needle site (n=5), transient paresthesias (n=7), and drowsiness after treatment (n=5).

Only one patient discontinued due to persistent discomfort after the session. Adherence was notable, with 96.8% of all 744 planned sessions being performed. Limitations of the study include the smaller-than-planned sample size due to COVID-19 pandemic restrictions, the exploratory analysis of neurological outcomes (which were secondary), the absence of blinding of clinical evaluators, and the use of a portable device instead of conventional electroneurography. Additionally, the absence of a sham group may have contributed to a placebo effect, although the persistence of benefits up to 4 months after treatment suggests genuine effects.

This study represents an important advance in the approach to DPN by focusing specifically on improving sensory function and reducing numbness, crucial aspects for preventing complications such as diabetic ulcers and amputations. The results suggest that acupuncture may fill an important therapeutic gap, offering benefits for symptoms that do not respond to conventional pharmacological treatment, with an excellent safety profile in a population already burdened with medications.