Importance: Management of painful diabetic peripheral neuropathy remains challenging. Most therapies provide symptomatic relief with varying degrees of efficacy. Tocotrienols have modulatory effects on the neuropathy pathway and may reduce neuropathic symptoms with their antioxidative and anti-inflammatory activities. Objective: To evaluate the efficacy of oral mixed tocotrienols for patients with diabetic peripheral neuropathy. Design, Setting, and Participants: The Vitamin E in Neuroprotection Study (VENUS) was a parallel, double-blind, placebo-controlled trial that recruited participants from January 30, 2011, to December 7, 2014, with 12 months of follow-up. This trial screened 14 289 patients with diabetes from 6 health clinics and ambulatory care units from 5 public hospitals in Malaysia. A total of 391 patients who reported neuropathic symptoms were further assessed with Total Symptom Score (TSS) and Neuropathy Impairment Score (NIS). Patients 20 years or older with a TSS of 3 or higher and an NIS of 2 or higher were recruited. Interventions: Patients were randomized to receive 200 mg of mixed tocotrienols twice daily or matching placebo for 12 months. Patients with hyperhomocysteinemia (homocysteine level ≥2.03 mg/L) received oral folic acid, 5 mg once daily, and methylcobalamin, 500 μg thrice daily, in both groups. Main Outcomes and Measures: The primary outcome was patient-reported neuropathy TSS (lancinating pain, burning pain, paresthesia, and asleep numbness) changes at 12 months. The secondary outcomes were NIS and sensory nerve conduction test result. Results: Of 391 eligible patients, 300 were recruited (130 [43.3%] male; mean [SD] age, 57.6 [8.9] years; mean [SD] duration of diabetes, 11.4 [7.8] years) and 229 (76.3%) completed the trial. The TSS changes between the tocotrienols and placebo groups at 12 months (-0.30; 95% CI, -1.16 to 0.56; P = .49) were similar. No significant differences in NIS (0.60; 95% CI, -1.37 to 2.65; P = .53) and sensory nerve conduction test assessments were found between both groups. In post hoc subgroup analyses, tocotrienols reduced lancinating pain among patients with hemoglobinA1C levels greater than 8% (P = .03) and normohomocysteinemia (homocysteine level <2.03 mg/L; P = .008) at 1 year. Serious adverse events in both groups were similar, except more infections were observed in the tocotrienols group (6.7% vs 0.7%, P = .04). Results reported were of modified intention-to-treat analyses. Conclusions and Relevance: Supplementation of oral mixed tocotrienols, 400 mg/d for 1 year, did not improve overall neuropathic symptoms. The preliminary observations on lancinating pain among subsets of patients require further exploration. Trial Registration: National Medical Research Registry Identifier: NMRR-10-948-7327 and clinicaltrials.gov Identifier: NCT01973400.
RCT Entities:
Importance: Management of painful diabetic peripheral neuropathy remains challenging. Most therapies provide symptomatic relief with varying degrees of efficacy. Tocotrienols have modulatory effects on the neuropathy pathway and may reduce neuropathic symptoms with their antioxidative and anti-inflammatory activities. Objective: To evaluate the efficacy of oral mixed tocotrienols for patients with diabetic peripheral neuropathy. Design, Setting, and Participants: The Vitamin E in Neuroprotection Study (VENUS) was a parallel, double-blind, placebo-controlled trial that recruited participants from January 30, 2011, to December 7, 2014, with 12 months of follow-up. This trial screened 14 289 patients with diabetes from 6 health clinics and ambulatory care units from 5 public hospitals in Malaysia. A total of 391 patients who reported neuropathic symptoms were further assessed with Total Symptom Score (TSS) and Neuropathy Impairment Score (NIS). Patients 20 years or older with a TSS of 3 or higher and an NIS of 2 or higher were recruited. Interventions: Patients were randomized to receive 200 mg of mixed tocotrienols twice daily or matching placebo for 12 months. Patients with hyperhomocysteinemia (homocysteine level ≥2.03 mg/L) received oral folic acid, 5 mg once daily, and methylcobalamin, 500 μg thrice daily, in both groups. Main Outcomes and Measures: The primary outcome was patient-reported neuropathy TSS (lancinating pain, burning pain, paresthesia, and asleep numbness) changes at 12 months. The secondary outcomes were NIS and sensory nerve conduction test result. Results: Of 391 eligible patients, 300 were recruited (130 [43.3%] male; mean [SD] age, 57.6 [8.9] years; mean [SD] duration of diabetes, 11.4 [7.8] years) and 229 (76.3%) completed the trial. The TSS changes between the tocotrienols and placebo groups at 12 months (-0.30; 95% CI, -1.16 to 0.56; P = .49) were similar. No significant differences in NIS (0.60; 95% CI, -1.37 to 2.65; P = .53) and sensory nerve conduction test assessments were found between both groups. In post hoc subgroup analyses, tocotrienols reduced lancinating pain among patients with hemoglobin A1C levels greater than 8% (P = .03) and normohomocysteinemia (homocysteine level <2.03 mg/L; P = .008) at 1 year. Serious adverse events in both groups were similar, except more infections were observed in the tocotrienols group (6.7% vs 0.7%, P = .04). Results reported were of modified intention-to-treat analyses. Conclusions and Relevance: Supplementation of oral mixed tocotrienols, 400 mg/d for 1 year, did not improve overall neuropathic symptoms. The preliminary observations on lancinating pain among subsets of patients require further exploration. Trial Registration: National Medical Research Registry Identifier: NMRR-10-948-7327 and clinicaltrials.gov Identifier: NCT01973400.
Authors: Dan Ziegler; Alexander Ametov; Alexey Barinov; Peter J Dyck; Irina Gurieva; Phillip A Low; Ullrich Munzel; Nikolai Yakhno; Itamar Raz; Maria Novosadova; Joachim Maus; Rustem Samigullin Journal: Diabetes Care Date: 2006-11 Impact factor: 19.112
Authors: Alesia Sadosky; Jack Mardekian; Bruce Parsons; Markay Hopps; E Jay Bienen; John Markman Journal: J Diabetes Complications Date: 2014-11-08 Impact factor: 2.852
Authors: Laima Brazionis; Kevin Rowley; Catherine Itsiopoulos; Colin Alexander Harper; Kerin O'Dea Journal: Diabetes Care Date: 2007-09-26 Impact factor: 19.112
Authors: Dan Ziegler; Phillip A Low; William J Litchy; Andrew J M Boulton; Aaron I Vinik; Roy Freeman; Rustem Samigullin; Hans Tritschler; Ullrich Munzel; Joachim Maus; Klemens Schütte; Peter J Dyck Journal: Diabetes Care Date: 2011-07-20 Impact factor: 19.112
Authors: Mohd Danial Mohd Efendy Goon; Nur Izzati Zulkanain; Siti Hamimah Sheikh Abdul Kadir; Sharaniza Ab Rahim; Musalmah Mazlan; Normala Abd Latip; Mardiana Abdul Aziz; Norizal Mohd Noor Journal: Transl Gastroenterol Hepatol Date: 2022-01-25
Authors: Yeek Tat Ng; Sonia Chew Wen Phang; Gerald Chen Jie Tan; En Yng Ng; Nevein Philip Botross Henien; Uma Devi M Palanisamy; Badariah Ahmad; Khalid Abdul Kadir Journal: Nutrients Date: 2020-05-23 Impact factor: 5.717
Authors: Giulia Di Stefano; Andrea Di Lionardo; Giuseppe Di Pietro; Giorgio Cruccu; Andrea Truini Journal: Pain Res Manag Date: 2021-04-26 Impact factor: 3.037