Frequency rhythmic electrical modulation system (FREMS) to alleviate painful diabetic peripheral neuropathy: a pilot, randomised controlled trial (The FREMSTOP study)

BACKGROUND: Frequency Rhythmic Electrical Modulated System (FREMS) is a non-invasive treatment for chronic pain conditions, but its place in the treatment algorithm for painful diabetic peripheral neuropathy (PDPN) is unknown.

METHODS: A pilot, open-label, randomised controlled trial in individuals with PDPN inadequately controlled on at least dual neuropathic pain treatments recruited from primary and secondary care. Participants were randomised 1:1 to FREMS + usual care (n = 13) versus usual care (n = 12). Primary outcome was change from baseline in perceived pain (assessed by visual analogue scale) at 12 weeks between treatment groups.

RESULTS: Of 25 participants, 14 (56%) were men, and 21 (84%) were White Europeans. Median (IQR) age and duration of diabetes were 64 (56, 68) and 14 (10, 20) years, respectively. At 12 weeks, FREMS showed improvements in perceived pain compared with baseline, although the change was not statistically significant from control group (-4.0[-5.0,0.4] vs. 0[-0.3,0.7], p = 0.087). There were significant improvements in pain with FREMS, assessed by McGill Pain questionnaire (p = 0.042) and Douleur neuropathique-4 questionnaire (p = 0.042). More participants on FREMS had greater than 30 percent reductions in perceived pain compared with controls [7/13(54%) vs 0/12(0%), p = 0.042] and significant improvements in Patient Global Impression of Change (p = 0.005). FREMS intervention had moderate benefits in quality of life, sleep, depression and pain medication use, but these were not statistically significant.

CONCLUSIONS: FREMS might be used to treat individuals with PDPN inadequately controlled on two classes of neuropathic pain medications and is associated with improvements in pain severity and perceived impact of treatment. A larger, appropriately designed trial assessing its impact in this population is needed.