The Effect of Pregabalin on Pain Related to Walking in Patients With Diabetic Peripheral Neuropathy

Pregabalin (LYRICA®) is a potent and specific ligand at the alpha-2-delta subunit of voltage-gated calcium channels. It is currently approved for adjunctive therapy for neuropathic pain conditions. Patients with diabetic peripheral neuropathy suffer from pain in their feet which interferes with their ability to walk which includes less walking, an altered gait, and altered balance. At night the peripheral neuropathy also interferes with their sleep patterns.The hypothesis of this study is that pregabalin, 150 mg bid, will reduce general daytime pain in patients diagnosed with diabetic peripheral neuropathy and that it will also reduce the level of pain associated with walking. Consequently, it is hypothesized that the reduction in pain will result in an increase in the amount of walking they do during the day, improvements in their gait, balance, risk of falls and sleep patterns.Pain and sleep quality will be assessed with questionnaires but objective measurements will be used to assess gait, balance, daytime activities (including walking) and sleep patterns. Statistical Power Calculations were based on the fact that this is a randomized, double-blind, placebo-controlled, 2-period crossover study to be conducted at a single site. Comparisons will be drawn at baseline, at the completion of each 6 weeks of treatment/placebo arm. The study has been powered at 0.80 for a two-tail analysis with a sensitivity to detect a 30% delta in pain perception in 40 subjects. From previous studies, the cross-over design suggested has achieved significance with 20 patients per group. Forty-four patients will be recruited in total. Significance will be established at an alpha level of 0.05. Both parametric and non parametric correlations will be carried out between the different variables measured and progressive logistic regression to determine the relative contributions of pain relief on the primary and secondary variables being measured in the study.