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Vitamin E = placebo for relief of neuropathic symptoms in patients with diabetes (VENUS)
Clinical Question
Do mixed tocotrienols (a naturally occurring subtype of vitamin E) improve neuropathic symptoms in patients with diabetes?
Bottom line
After one year, patients with diabetes and neuropathic pain who take tocotrienols have the same degree of symptom relief as those who take placebo. 1b-
Reference
Study design: Randomized controlled trial (double-blinded)
Funding: Industry + govt
Setting: Outpatient (primary care)
Synopsis
These authors recruited patients at least 20 years of age with diabetes and peripheral neuropathy. The patients had to have a Total Symptom Score (TSS) of 3 or higher and a Neuropathy Impairment Score (NIS) of 2 or higher to be included. The authors excluded patients with a glycohemoglobin level of more than 12%, any substance abuse disorder or psychiatric disorder, serum creatinine level of more than 1.7 mg/dL (150 micromoles/liter), or liver transaminases level of more than 5 times the upper limit of normal. They also excluded pregnant or lactating women, immunocompromised patients, and those with symptomatic peripheral vascular disease. The researchers randomized eligible patients to receive placebo (n = 150) or mixed tocotrienols, a naturally occurring subtype of vitamin E, 200 mg twice daily (n = 150) for 12 months. The patients had diabetes for an average of 11 years. A minimal reduction of 1.83 in the TSS and 2 in the NIS are clinically meaningful. At the end of 1 year, each group had meaningful improvements in symptoms, however, the change in TSS and NIS was similar in each treatment group in spite of worsening glycemic control in the placebo-treated patients. Slightly more patients taking tocotrienols stopped taking medication because of adverse events (8% vs 4.7%).
Reviewer
Henry C. Barry, MD, MS
Professor
Michigan State University
East Lansing, MI
Comments
Should we be surprised ?
What is the role of placebos on evidence based medicinWhat are the ethical guidelines re placebo therapy
I think worsening of glycemic control in placebo recipients suggests a study of Vitamin E in glycemic maintenance. What do you think?
good poem
Interesting. Exclusion criteria included elevated transaminases 5 x ULN, presumably because liver disease increases the risk of vitamin E toxicity. Dose was 200 mg b.i.d. for 12 months, suggesting that this is a safe dosage (?). Although not superior to placebo, I wonder why so many patients in the Vitamin E group stopped their other medications? This could be a desirable outcome, either because the Vitamin E is working, because the Vitamin E is a safer placebo, or because patients start to recognize more clearly when adverse drug side effects outweigh the benefits of medications and are more willing to stop medications if they are at least 'taking something' (i.e. Vitamin E) for their symptoms. Reporting of safety/ side effect data in the POEM would be helpful.
Many patient with diabetic neuropathy need to be on bit E
Why does anyone make vitamin E anymore? I don't know of any reliable evidence that it improves any actual health outcomes. Every trial that suggested a benefit to taking it has been reversed by better/larger studies.
Bonne information et à la fin surtout utile pour savoir quoi ne pas prescrire ou recommander