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Michael Smolek, Neil Notaroberto, Lisa Pradillo, Arley Jaramillo, Kaci Lee; Vitamin B Intervention in Non-Proliferative Diabetic Retinopathy. Invest. Ophthalmol. Vis. Sci. 2013;54(15):217. doi: https://doi.org/.
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A pilot study was conducted to determine whether biologically active vitamin B intervention is effective in reducing the signs or symptoms of nonproliferative diabetic retinopathy (NPDR) in type 2 diabetes mellitus patients. Vitamin B mediates homocysteine levels and contributes to the production of nitric oxide, both of which play a critical role in vascular repair and maintenance.
An open-label, one-arm, uncontrolled, prospective study was conducted on 10 NPDR patients newly prescribed with Metanx®, which is currently used for controlling the symptoms of diabetic peripheral neuropathy. A standard daily dose of Metanx is two tablets. Each tablet contains: 3 mg L-methylfolate Calcium (vitamin B9 as Metafolin® - Merck KGaA, Darmstadt, Germany); 35 mg Pyridoxal-5′-Phosphate (vitamin B6); and 2 mg Methylcobalamin (vitamin B12). Two main outcome objectives were followed: change in mean retinal threshold sensitivity measured by microperimetry (MAIA®, CenterVue, Padova, Italy) and change in mean central retinal thickness measured by spectral domain OCT (Spectralis®, Heidelberg Engineering, Carlsbad, CA, USA). Subjects were prescribed with Metanx at the month-0 baseline examination and seen once per month for 6 months. All subjects gave informed consent.
Three subjects were lost to follow-up. Of the remaining 7 subjects, 2 of 14 eyes had significant foveal edema and MAIA testing was unreliable due to poor fixation. The remaining 12 eyes exhibited significant improvement at 3 months for threshold sensitivity (p<0.001) and significant improvement in retinal thickness at 6 months (p=0.012). The trend for improvement for retinal sensitivity was non-linear and reached a plateau by month 3. The decrease in retinal thickness over time had a linear trend that was significant (R2=0.625; p=0.034).
Biologically active vitamin B appears to have a significant effect on NPDR. Further research is needed to determine whether this trend continues with time, and whether the efficacy can be adjusted by the dosage. More critically, a placebo-controlled study needs to be performed to rule out any potential bias in the results.
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