RESUMO
CONTEXT: Peripheral neuropathy is one of the most common complications of diabetes. OBJECTIVES: The purpose of this study was to evaluate the effects of photon stimulation on pain intensity, pain relief, pain qualities, sensation and quality of life (QOL) in patients with painful diabetic peripheral neuropathy. METHODS: In this randomized, placebo-controlled trial, patients were assigned to receive either four photon stimulations (n=63) or four placebo (n=58) treatments. Pain intensity, pain relief, and pain qualities were assessed using self-report questionnaires. Sensation was evaluated using monofilament testing. QOL was measured using the Medical Outcomes Study Short Form-36 (SF-36). Multilevel regression model analyses were used to evaluate between-group differences in study outcomes. RESULTS: No differences, over time, in any pain intensity scores (i.e., pain intensity immediately post-treatment, average pain, worst pain) or pain relief scores were found between the placebo and treatment groups. However, significant decreases, over time, were found in some pain quality scores, and significant improvements in sensation were found in patients who received the photon stimulation compared with placebo. In addition, patients in the treatment group reported significant improvements in SF-36 social functioning and mental health scores. Findings from a responder analysis demonstrated that no differences were found in the percentages of patients in the placebo and treatment groups who received 30% or more or 50% or more reduction in pain scores immediately post-treatment. However, significant differences were found in the distribution of the changes in pain relief scores, with most of the patients in the photon stimulation group reporting a slight (28.6%) to moderate (34.9%) improvement in pain relief from the beginning to the end of the study compared with no change in pain relief (43.1%) in the placebo group. CONCLUSION: Four treatments with photon stimulation resulted in significant improvements in some pain qualities, sensation, and QOL outcomes in a sample of patients with a significant amount of pain and disability from their diabetes. A longer duration study is needed to further refine the photon stimulation treatment protocol in these chronically ill patients and to evaluate the sustainability of its effects.
