Efeito da Terapia a Laser de Baixa Intensidade no Manejo da Neuropatia Periférica Diabética: Ensaio Clínico Randomizado

Abstract

This study aimed to evaluate the effects of local application of low-intensity laser therapy associated with modified Intravascular Laser Irradiation of Blood (ILIB) and local application alone in the management of diabetic peripheral neuropathy in patients with type 2 diabetes mellitus. This is a randomized clinical trial conducted in four basic health units. The sample consisted of 30 participants, equally distributed into two intervention groups, with Intervention Group 1 receiving local application of low-intensity laser therapy (LLLT) associated with modified ILIB and Intervention Group 2 receiving local application of LLLT alone. The local application of LLLT was performed with an infrared laser source, using a fluence of 3 joules/cm2, applied punctually to six specific points on each foot, with each point receiving 30 seconds of application, totaling 3 minutes on each foot and 6 minutes of bilateral local intervention. The modified ILIB technique was applied transcutaneously to the radial artery, under red light, in continuous mode, lasting 20 minutes per session. In both intervention groups, 12 sessions were held on Mondays, Wednesdays, and Fridays for four weeks. Data collection took place between June 2024 and March 2025. In S1, sociodemographic and clinical information, presence of neuropathic pain symptoms, clinical manifestations of DPN, and assessment of the lower limbs were collected, focusing on the Nursing Outcome Indicators (NOC) Peripheral Neurological Status. In S2, information on the participants' quality of life was obtained. In S3, S6, and S9, the lower limb assessments described above were performed. In S12, the S1 instruments were reapplied and the lower limbs were assessed. Vital data were collected before and after each session. To verify changes between the pre-intervention and post-intervention moments in continuous variables with paired measures, the Wilcoxon test was applied, and 95% confidence intervals and a significance level of p < 0.05 were adopted. The study was approved by the Ethics Committee of the Federal University of Maranhão (opinion 6,842,223) and registered in the Brazilian Registry of Clinical Trials. The sample consisted mainly of females (66.7%), brown race/skin color (56.7%), married or in a stable union (66.7%), and aged over 60 years (56.7%). Most participants had incomplete elementary school education (33.3%). The outcomes with significant improvement in Intervention Group 1 were: sensation of numb legs and/or feet, presence of muscle cramps, improvement in the left Achilles reflex and in the NOC indicators regarding peripheral neurological status such as Sensitivity and Hyperesthesia in the left lower extremity, Pain in both lower extremities, and Paresthesia in the right lower extremity. In Intervention Group 2, improvements were observed in variables such as burning or stinging pain and stinging in the legs and/or feet, dryness and cracks in the skin of the feet, an NOC indicator related to the peripheral neurological state Paresthesia in both lower extremities, in addition to the Pain domain related to quality of life for people with foot problems assessed by the Neuroqol instrument. The intervention protocols in Intervention Groups 1 and 2 did not show statistically significant differences in the intergroup comparison regarding the management of DPN. However, it was observed that Intervention Group 1 stood out in several clinical outcomes related to pain, neurological sensitivity and functional parameters. The study findings reinforce the importance of expanding the use of these technologies in the context of primary care and of promoting new controlled clinical trials that contribute to the advancement of evidence-based practice.