Effects and mechanisms of low-frequency transcutaneous electrical nerve stimulation in relieving common multimorbidity in older adults: study protocol for a randomized controlled trial

Background: Multimorbidity (≥2 co-existing conditions in an individual), especially co-existing essential hypertension (EH), type 2 diabetes mellitus (T2DM), and hyperlipidemia two or above, is a major global health challenge with substantial impact on individuals, carers and society. This trial aims to examine the efficacy of integrating low-frequency transcutaneous electrical nerve stimulation (Lo-TENS) into the management of multimorbidity (co-existing EH, T2DM, and hyperlipidemia two or above) in older adults and explore the underlying mechanisms through which Lo-TENS may alleviate the clinical indicators of multimorbidity, providing insights into its potential value as a novel adjunctive treatment modality. Methods: This prospective, randomized controlled trial (RCT) will enroll 50 older adults with multimorbidity, and randomly assign them to one of the two groups: 1) Lo-TENS plus routine clinical management group; or 2) sham stimulation plus routine clinical management group. Participants in each group will receive their respective stimulation one 30 min session/day, 5 days/week, for 4 consecutive weeks. The primary outcomes of interest are blood pressure, blood sugar and blood lipid, with secondary outcomes encompassing heart rate variability and various biochemical indicators. Comprehensive assessments will be performed at baseline, immediately post-intervention, and at 4-week follow-up. Discussion: This trial will provide evidence on the effectiveness of Lo-TENS on clinical outcomes in multimorbidity in older adults, and decipher the working mechanisms of Lo-TENS to multimorbidity. Trial registration: Chinese Clinical Trial Registry Platform: www.chictr.org.cn (No. ChiCTR2400093956).