Effect of a Peer Support Intervention on Glycemic Control and Economic Burden Among Patients With Diabetes on Follow-up at a Tertiary Hospital: A Randomized Controlled Trial
Phase: NA
Conditions: Peer Support Intervention
Sponsor: Addis Ababa University

Page 1 of 6 
 
Study Protocol and SAP 
 
 
 
 
 
 
Official Title: Effect of a Peer Support Intervention on Glycemic Control and Economic 
Burden Among Patients with Diabetes (PSI) 
 
    
 
  
 
 
ClinicalTrials.gov ID (NCT number): NCT07499375 
 
 
Protocol Date: January 1/ 2025 
 
 
 
 

Page 2 of 6 
 
Scientific Background 
Diabetes imposes a growing global burden due to rising care costs and reduced quality of life from 
its complications. There is increasing interest in the role that peers may play to support positive 
health behaviors in diabetes. However, studies which evaluating both clinical effectiveness and 
economic feasibility of peer support interventions remain limited to date. Thus, this study aimed 
to evaluated the effect of a group-based peer support intervention on glycemic control and its 
implementation cost among patients with diabetes who attended follow-up at a tertiary hospital. 
Study Objectives 
➢ To assess the effect of a peer support group intervention on Glycemic control among 
patients with diabetes on follow up at ACSH 
➢ To determine the implementation cost of peer support group intervention among 
patients with diabetes on follow up at ACSH  
Study Design & Methods 
Study Setting 
This study was conducted as part of a randomized controlled trial (RCT) under evaluating the 
effectiveness of a peer support intervention among patients with diabetes attending Ayder 
Comprehensive Specialized Hospital (ACSH), a tertiary referral hospital in Northern Ethiopia. The 
trial employed a parallel-group design with a 1:1 allocation ratio to intervention and control arms. 
The study followed the Consolidated Standards of Reporting Trials (CONSORT) guidelines, and 
participant flow was reported using a CONSORT flow diagram. The detailed trial protocol and 
overall methodology have been described elsewhere.  
Study Design and Period 
A randomized controlled trial (RCT) design was employed from January to September 2025 to 
evaluate the effect of a peer support intervention among patients with diabetes attending ACSH. 
This trial has been registered and can be accessed at: https://clinicaltrials.gov/study/NCT07499375 
which initially released on March 24, 2026. 
 
 
 

Page 3 of 6 
 
Study participants and Sample size Determination  
This study has involved three group of study participants whose were categorized as the peer 
support group, the intervention group and the control group who were on regular follow-up at the 
ACSH diabetic clinic. All participants were required to have a confirmed diagnosis of diabetes and 
to be willing to provide informed consent. The sample size for this study was derived from the 
main randomized controlled trial, which was powered to detect differences in medication 
adherence between groups. For the intervention and control groups, the sample size was calculated 
using the statistical superiority design formula for continuous variables: n = [(Z₁ + Z₂)² × (2S²)] / 
d². In this formula, Z₁ represents the z-score for a 95% confidence level (1.96), Z₂ corresponds to 
a power of 80% (0.84).  The standard deviation (S = 4) was estimated based on the range of scores 
from the Morisky Medication Adherence Scale with eight items (MMAS-8), which ranges from 0 
(indicating poor adherence) to 8 (indicating high adherence). A minimum clinically meaningful 
difference of 2 points (d = 2) in adherence scores between the groups was considered for sample 
size calculation. Thus, considering the lost to follow up a total of 100 eligible patients with diabetes 
were recruited using a simple random sampling method with 50 participants assigned to the 
intervention group and 50 to the control group. Besides, five participants were purposively selected 
for the peer support group based on predefined eligibility criteria. Selection was done in 
collaboration with clinical service providers at the diabetic center to ensure the inclusion of 
experienced individuals, following guidance from validated studies on peer support interventions 
for chronic diseases. 
Standard Care 
Scheduled consultations with a physician, laboratory investigations and medication refill were the 
standard care services delivered for patients with diabetes during the clinic’s service days at the 
diabetic center of the hospital. Follow-up appointments are typically scheduled every two to three 
months. Newly diagnosed patients receive individualized counseling from the nurse on duty, 
addressing diabetes-related and patient-specific concerns. Additionally, patients collect their 
prescribed medications from the hospital pharmacy up on visiting the hospital for follow up in 
which standard pharmacy care was also served. Thus, in this trial both groups received this 
standard health care service equally.  
Peer Support Intervention and Procedures  

Page 4 of 6 
 
The study was conducted in two phases. Phase I involved the recruitment and preparation of the 
peer support group (n = 5). These individuals were selected in advance and remained consistent 
throughout the intervention period. One registered nurse was recruited to serve as a facilitator for 
the peer support sessions. The recruited peer educator attended an initial 2-days training program 
on how to facilitate and structure the consecutive sessions which included role-playing exercises 
to prepare them for effective communication and engagement with intervention group members. 
They were primarily trained in their local language (Tigrigna) to educate and share their experience 
to peers on scheduled sessions focused on treatment adherence, self-care behaviors, and diabetes-
related knowledges which was adopted from the Internation Diabetes Federation peer leader 
manual. 
On Phase II, enrollment of the intervention and control group was continued during their regular 
appointments at the diabetic clinic. Both groups were matched in terms of sociodemographic 
characteristics and disease-related factors. While the control group received baseline assessments 
only and continued with standard care, members of the intervention group attended a one-hour 
orientation session to explain the study's objectives, potential risks of withdrawal, and the 
importance of sustained participation. Following this, each peer supporter was assigned to a group 
of 10 intervention participants and formed five peer-led-intervention subgroups. 
The peer support intervention was delivered through scheduled, one-hour group session during 
regular clinic appointments. These interventions were conducted in the 2nd, 4th and 6th months, i.e., 
for three rounds over the study period for each group. Each group member was expected to 
participate in all the three sessions, which were structured around three core components: (a) 
sharing personal experiences and knowledge about diabetes and its complications, blood glucose 
triggering factors and providing psychosocial support focused on the self-management (disease-
related component); (b) offering education and encouragement for medication adherence 
(medication adherence component); and (c) supporting the integration of dietary and physical 
activity recommendations into daily routines (behavioral component). The principal investigator 
conducted close follow-up of the intervention sessions to document the topics covered during each 
session and address any challenges encountered during the implementation. Monthly debriefing 
sessions were conducted to discuss their experiences and challenges. Feedback on their 
performance was provided based on each group sessions. 

Page 5 of 6 
 
Outcome measures 
Glycemic control was evaluated using glycated hemoglobin (HbA1c) levels measured at baseline 
and at the end of the six-month follow-up period. All measurements were performed in the hospital 
laboratory following standard clinical procedures. HbA1c values were used to assess changes over 
time within and between the intervention and control groups. The economic evaluation focused on 
the implementation cost of the peer-support intervention from the program/provider perspective. 
Cost components included peer supporter recruitment, intervention group recruitment, peer 
supporter training, peer-support session delivery, and general program implementation activities. 
Resource utilization data were documented prospectively using a structured costing tool developed 
for this study. All costs were valued in United States Dollars ($) for the 2025 costing year. Where 
applicable, estimates were standardized and inflation-adjusted to the reference currency year to 
ensure comparability 
Data collection procedures 
Data were collected by trained data collectors using interviewer-administered questionnaires and 
medical record reviews. Baseline data included sociodemographic characteristics, clinical 
information, glycemic measures, and cost-related variables. endline assessments were conducted 
after three consecutive follow ups using the same tools and procedures to ensure consistency. 
Because of the behavioral nature of the intervention, participants and peer supporters were not 
blinded. However, trained data collectors who conducted baseline and endline assessments were 
blinded to treatment allocation. Laboratory personnel performing biochemical measurements were 
also not informed of group assignment to reduce detection bias 
 
Eligibility Criteria  
 
Study Population and Eligibilities  
The study involved diabetic patients aged 18 to 65 years who were receiving follow-up care at 
ACSH. Participants were divided into three groups whose were categorized as the peer support 
group, the intervention group and the control group.  Eligible participants of the peer support group 
had a minimum of 10th grade educational background with more than three years of disease 
duration, stable glycemic control with HbA1C <7.5%), a documented history of regular follow-up 
at ACSH. Besides, the intervention group were those who received the peer-led educational 

Page 6 of 6 
 
sessions, which aimed to improve adherence to diabetes treatment, enhance self-care behaviors, 
and increase diabetes-related knowledge. Eligible participants of this group were those who had 
on at least one diabetes medication, most recent HbA1C value of ≥7.5% based on information 
collected by the research team at point of care HbA1C testing and those had regular follow-up 
visits at ACSH. The control group comprised patients with diabetes meeting similar eligibility 
criteria as the intervention group but received standard diabetes care during routine clinic visits 
without additional peer support.  
Patients with diabetes who declined to participate in any of the groups, those diagnosed with other 
concurrent endocrine disorders (such as thyroid disease, obesity, or gestational diabetes) and 
chronic diseases like cardiac heart failure, hepatitis and cancer were excluded. Additionally, those 
enrolled in other educational programs during the study period and health professionals were 
excluded from this study. 
Statistical Considerations 
Data were entered into Epi-Data version 4.6 and exported to SPSS version 25 for analysis. 
Descriptive statistics such as frequencies, percentages, means, and standard deviations were used 
to summarize sociodemographic, clinical, and behavioral characteristics of participants. 
Medication adherence, diabetes knowledge, and self-care practice scores were calculated 
according to their respective validated scales. The effect of the peer support group intervention 
within-group and between-group was assessed and comparisons were performed. Paired t-tests 
were used to determine changes in the outcome variables within each group (intervention and 
control) before and after the intervention. Independent sample t-tests were applied to compare 
mean differences between groups. The effect of the peer support intervention on glycemic control 
and economic burden was estimated using a difference-in-differences (DiD) approach, comparing 
changes from baseline to endline between the intervention and control groups.