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What Does the Evidence Reveal About Spinal Cord Stimulation for Painful Diabetic Neuropathy?
Symptoms of diabetic peripheral neuropathy (DPN) pose significant challenges for patients and providers. A poster presented at the 2023 American Podiatric Medical Association (APMA) National reviewed 3 randomized controlled trials to investigate the performance of spinal cord stimulation (SCS) versus conventional medical management (CMM) for painful DPN.1 The poster authors noted that CMM may often include gabapentin, pregabalin, tricyclic antidepressants, and serotonin-norepinephrine reuptake inhibitors, but that many patients discontinue them within months.2
Two of the poster authors cite side effects and lack of efficacy as challenges patients and clinicians face with CMM for DPN. “One thing that can improve efficacy and longer term treatment is implementing a low dose, with increased titration, of gabapentin starting with a subtherapeutic dose,” says Stephen Barrett, DPM, MBA, FACFAS, FAENS.
What is the Structure of the Existing Research?
The poster authors looked at 3 RCTs,3-5 evaluating primary outcome measures, primary endpoint duration, demographics, intervention, treatment effect size, and quality of life (QOL) based on an intention-to-treat principle. They noted that 2 of the studies originated in Europe,3,4 with industry grant support, and that the remaining study was industry-sponsored out of the United States.5 Primary endpoints in the studies included definitions of response as being greater than or equal to 50% reduction in pain or specific milestones on the Patient Global Impression of Change scores for pain and sleep. Exact parameters for the pain reduction varied among the studies.3-5 EQ-5D questionnaires informed the QOL data, and the length of the primary endpoint was between 3-6 months, depending on the original study.3-5 Some of the studies3,5 evaluated mean hemoglobin A1c, while one did not.4
Alfred Glover, DPM, FACFAS, also a poster co-author, feels that these studies present possible alternatives to CMM, which may additionally mitigate opioid use and other high-risk treatment courses.
What Did the Authors Find Regarding Treatment Impact?
A total of 312 patients with DPN among all 3 studies contributed to the data, most of which had type 2 diabetes.3-5 The authors of the poster found that the SCS cohorts all demonstrated significantly more responders to treatment (59% vs 7%, 63% vs 5%, and 66.4% vs 11.7%) than the CMM control arms.1 Treatment effect size, a metric used by the American Academy of Neurology (AAN) measures the impact of an intervention, with greater than 20% considered a large treatment effect.10 The difference in treatment effect size between the control and SCS cohorts in each study for the primary endpoint was between 52 and 58%.1
“Clearly, when you look at a comparison to the CMM control arm, the outcomes of SCS are very encouraging,” says Dr. Barrett.
How Did Quality of Life Change?
In the 3 RCTs examined, QOL improved (by EQ-5D metrics) by an average of 0.26 at 6 months and 0.24 at 12 months.1 However, the authors noted that literature on traditional SCS1,3,4,7 shows greater improvement in quality of life compared to the evidence from a study on high-frequency SCS.1,8
What Should Clinicians Remember From This Study?
The authors concluded that all 3 RCTs presented exhibit the superior effectiveness of SCS compared to CMM.1 They commented that the variety of primary endpoint descriptions contributed to meaningful assessments of pain reduction with SCS and pointed out that very few patients regressed neurologically with SCS when measured. Prolonged follow-up of 18 months8 and 10 years9 also showed similar outcomes. The authors contended that the evidence supports consistent positive outcomes for painful DPN when treated with spinal cord stimulation.
“We want (clinicians) to understand that there are viable alternatives, says Dr. Glover. “SCS is an excellent alternative to have in your armamentarium.”
Created in partnership with the American Podiatric Medical Association.
References
1. Barrett S, Glover A, Dann T, et al. Consistent outcomes from multiple RCTs support SCS for the treatment of painful DPN. Poster presented at APMA National. July 2023, Nashville, TN.
2. Sloan G, Alam U, Selvaragjah D, Tesfaye S. The treatment of painful diabetic neuropathy. Current Diabetes Rev. 2022;18(5):e070721194556.
3. Slangen R, Schaper NC, Faber CG, et al. Spinal cord stimluation and pain relief in painful diabetic peripheral neruopathy: a prospective two-center randomized controlled trial. Diabetes Care. 2014;37(11):3018-3024.
4. de Vos CC, Meier K, Zaalberg PB, et al. Spinal cord stimulation in patients with painful diabetic neuropathy: a multicentre randomized clinical trial. Pain. 2014;155(11):2526-2431.
5. Petersen EA, Stauss TG, Scowcroft JA, et al. Effect of high-frequency (10-kHz) spinal cord stimulation in patients with painful diabetic neuropathy: A randomized clinical trial. JAMA Neurology. 2021;78(6):687-698.
6. Bril V, England J, Franklin GM, et al. Evidence-based guideline: treatment of painful diabetic neuropathy: report of the American Academy of Neurology, the American Association of Neuromuscular and Electrodiagnostic Medicine, and the American Academy of Physical Medicine and Rehabilitation. Neurology. 2011;76(20):1758-1765.
7. van Beek M, Slangen R, Schaper NC, et al. Sustained treatment effect of spinal cord stimulation in painful diabetic peripheral neuropathy: 24-month follow up of a prospective two-center randomized controlled trial. Diabetes Care. 2015;38(9):e132-4.
8. Petersen EA, Stauss TG, Scowcroft JA, et al. High-frequency 10-kHz spinal cord stimulation improves health-related quality of life in patients with refractory painful diabetic neuropathy: 12-month results from a randomized controlled trial. Mayo Clin Proc Innov Qual Outcomes. 2022;6(4):347-360.
9. Zuidema X, et al. Long-term evaluation of spinal cord stimulation in patients with painful diabetic polyneuropathy: An eight-to-ten-year prospective cohort study. Neuromodulation. 2022:26(5):1074-1080.
