NMES, Exercise, and Glycemic Control in Older Adults With Type 2 Diabetes (NMES4GlyCon)

Neuromuscular Electrical Stimulation Versus Combined Aerobic and Resistance Exercise Versus Health Literacy Intervention for Glycemic Control in Institutionalized Older Adults With Type 2 Diabetes: A Randomized Controlled Trial

Adults aged 60 years and older with type 2 diabetes living in nursing homes may experience difficulty participating in conventional exercise programs because of frailty, mobility limitations, or chronic health conditions. This randomized controlled trial compares three 12-week non-pharmacological interventions for glycemic management: neuromuscular electrical stimulation (NMES), supervised combined aerobic and resistance exercise, and a structured health literacy intervention. Participants will be randomly assigned to one of the three groups. The primary outcome is weekly mean fasting capillary glucose. Secondary outcomes include health-related quality of life, treatment satisfaction, adherence, and safety. The study aims to identify feasible and clinically relevant strategies for improving diabetes management in institutionalized older adults.

Study Overview

• Status: Enrolling by invitation
• Conditions: Type 2 Diabetes Mellitus; Aging; Hyperglycemia Due to Type 2 Diabetes Mellitus
• Intervention / Treatment: Device: Neuromuscular Electrical Stimulation; Behavioral: Combined Aerobic and Resistance Exercise; Behavioral: Health Literacy Education

Detailed Description

This randomized controlled trial investigates the comparative effectiveness of three non-pharmacological strategies for glycemic management in institutionalized older adults with type 2 diabetes mellitus living in nursing homes and long-term care facilities in Portugal.

Older adults residing in institutional settings frequently present with reduced mobility, frailty, multimorbidity, and reduced participation in conventional exercise programs. These factors contribute to impaired glycemic control and increased risk of diabetes-related complications. Although exercise is recommended as a core component of diabetes management, implementing structured exercise programs in institutionalized older populations may be challenging because of physical limitations, reduced functional capacity, and low adherence.

Neuromuscular electrical stimulation (NMES) has been proposed as a potential alternative or adjunctive intervention for individuals with limited tolerance to conventional exercise. By eliciting involuntary muscle contractions, NMES may promote metabolic and muscular adaptations associated with improved glucose regulation while requiring lower physical demand from participants. However, evidence regarding its effectiveness in institutionalized older adults remains limited.

This study compares NMES, supervised combined aerobic and resistance exercise, and a structured health literacy intervention focused on diabetes self-management and healthy behaviors. The inclusion of an educational comparator allows exploration of the relative contribution of physiological and behavioral approaches to glycemic management.

The trial is designed to evaluate the feasibility, acceptability, and potential clinical effectiveness of these interventions in real-world long-term care settings. The findings may contribute to the development of more accessible and adaptable non-pharmacological strategies for older adults with functional limitations and reduced exercise capacity.

• Study Type: Interventional
• Enrollment (Estimated): 75
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Portugal
  • Viseu District
    • Viseu, Viseu District, Portugal
      • Nursing Homes and Long-Term Care Facilities in Central Portugal

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Confirmed diagnosis of type 2 diabetes mellitus.
• Age 60 years or older.
• Resident in a nursing home or similar long-term care facility in Portugal.
• Able to understand study procedures and provide informed consent.
• Stable antidiabetic medication regimen for at least 12 weeks before enrollment.

Exclusion Criteria:

• Severe cognitive impairment or inability to provide informed consent.
• Acute or unstable medical condition making participation unsafe.
• Contraindications to moderate-intensity exercise.
• Implanted electronic devices (e.g., pacemaker, implantable cardioverter-defibrillator).
• Skin lesions or dermatological conditions preventing safe electrode placement.
• Any condition judged by the clinical team to preclude safe participation.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Neuromuscular Electrical Stimulation; Participants receive bilateral quadriceps neuromuscular electrical stimulation three times per week, using surface electrodes applied bilaterally to the quadriceps muscles (5 Hz frequency, 400 μs pulse duration, 4 s ON / 12 s OFF duty cycle), for 12 weeks. Sessions last 30 minutes with progressive intensity to the maximum tolerable level.	Device: Neuromuscular Electrical Stimulation; Bilateral quadriceps neuromuscular electrical stimulation delivered three times per week for 12 weeks. Sessions last 30 minutes using surface electrodes with progressive intensity to the maximum tolerable level.
Active Comparator: Combined Aerobic and Resistance Exercise; Participants perform supervised combined aerobic and resistance exercise three times per week for 12 weeks. Each session lasts 30 minutes and includes warm-up, aerobic training, resistance exercises, and cool-down.	Behavioral: Combined Aerobic and Resistance Exercise; Supervised combined aerobic and resistance exercise delivered three times per week for 12 weeks. Each 30-minute session includes warm-up, aerobic training, resistance exercises, and cool-down.
Other: Health Literacy Education; Participants attend structured health literacy education sessions three times per week for 12 weeks focused on diabetes self-management, physical activity, nutrition, medication adherence, and glucose monitoring.	Behavioral: Health Literacy Education; Structured education sessions delivered three times per week for 12 weeks focused on diabetes self-management, nutrition, physical activity, medication adherence, and glucose monitoring.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Weekly Mean Fasting Capillary Glucose	Mean fasting capillary blood glucose calculated from at least three fasting measurements per week when feasible during the intervention period, and assessed at 30-, 60-, and 90-day follow-up.	Baseline, weekly during the 12-week intervention period, and at 30-, 60-, and 90-day follow-up

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Audit of Diabetes-Dependent Quality of Life (ADDQoL-18)	Health-related quality of life assessed using the Portuguese validated version of the Audit of Diabetes-Dependent Quality of Life (ADDQoL-18). The ADDQoL-18 evaluates the perceived impact of diabetes on quality of life across multiple domains. Weighted impact scores range from -9 (maximum negative impact of diabetes on quality of life) to +3 (maximum positive impact), with lower scores indicating worse diabetes-related quality of life and higher scores indicating better quality of life.	Baseline, Week 12 (post-intervention), Day 30 follow-up, Day 60 follow-up, Day 90 follow-up
Overall Treatment Satisfaction (3-item adapted questionnaire based on the Diabetes Treatment Satisfaction Questionnaire)	Overall treatment satisfaction assessed using one item from a 3-item adapted questionnaire derived from the Diabetes Treatment Satisfaction Questionnaire (DTSQ). Scores range from 0 to 6, with higher scores indicating greater satisfaction with current treatment.	Week 12 (post-intervention)
Perceived Frequency of Hyperglycemia (3-item adapted questionnaire based on the Diabetes Treatment Satisfaction Questionnaire)	Perceived frequency of unacceptably high blood glucose assessed using one item from a 3-item adapted questionnaire derived from the Diabetes Treatment Satisfaction Questionnaire (DTSQ). Scores range from 0 to 6, with higher scores indicating greater perceived frequency of hyperglycemia.	Week 12 (post-intervention)
Perceived Frequency of Hypoglycemia (3-item adapted questionnaire based on the Diabetes Treatment Satisfaction Questionnaire)	Perceived frequency of unacceptably low blood glucose assessed using one item from a 3-item adapted questionnaire derived from the Diabetes Treatment Satisfaction Questionnaire (DTSQ). Scores range from 0 to 6, with higher scores indicating greater perceived frequency of hypoglycemia.	Week 12 (post-intervention)
Treatment Adherence	Adherence quantified as percentage of scheduled sessions attended (completed sessions out of 36 total scheduled sessions). Reasons for missed sessions recorded when available.	Throughout 12-week intervention period

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Baseline Physical Activity Level	Measurement of baseline physical activity level using a pedometer, expressed as the average daily step count recorded over 7 consecutive days. This measure will be used as a covariate in the analysis to adjust for potential baseline differences.	Baseline.
Baseline Physical Fitness Level	Assessment of baseline physical fitness using the Senior Fitness Test (SFT), which includes multiple components (2-minute step test, chair stand test, arm curl test, chair sit-and-reach test and back scratch test). These measures will be used as covariates in the analysis to adjust for potential baseline differences.	Baseline.

Collaborators and Investigators

• Sponsor: University of Salamanca
• Collaborators: University of Salamanca; Instituto Piaget; Escola Superior de Tecnologia da Saúde de Coimbra
• Investigators: Principal Investigator: Carlos Tavares, PT, MSc, University of Salamanca; Study Director: Rui Gonçalves, PhD, Polytechnic University of Coimbra; Study Chair: Rocío Llamas-Ramos, PhD, University of Salamanca

Study record dates

Study Major Dates

• Study Start (Actual): October 27, 2025
• Primary Completion (Estimated): August 30, 2026
• Study Completion (Estimated): August 30, 2026

Study Registration Dates

• First Submitted: February 26, 2025
• First Submitted That Met QC Criteria: February 26, 2025
• First Posted (Actual): March 4, 2025

Study Record Updates

• Last Update Posted (Actual): May 13, 2026
• Last Update Submitted That Met QC Criteria: May 7, 2026
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: Exercise Training; Health Literacy; Neuromuscular Electrical Stimulation; Older Adults; Randomized Controlled Trial; Aerobic Exercise; Resistance Exercise; Glycemic Control; Nursing Homes; NMES
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Nutritional and Metabolic Diseases; Diabetes Mellitus, Type 2
• Other Study ID Numbers: NMES_T2DM_2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data underlying the results reported in publications arising from this trial will be shared, including demographic variables, baseline characteristics, intervention allocation, outcome data, and statistical analysis datasets.
• IPD Sharing Time Frame: Beginning 6 months after publication of the primary results and ending 5 years after publication.
• IPD Sharing Access Criteria: Access will be provided to researchers who submit a methodologically sound proposal. Requests will be reviewed by the study investigators. Data will be shared after approval, subject to ethical and legal requirements, and after signing a data access agreement.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No