Living Together With Chronic Disease: Informal Support for Diabetes Management in Vietnam (VALID) - Gestational Diabetes in Vietnam - Phase II
Phase: NA
Conditions: GDM
Sponsor: Thai Binh University of Medicine and Pharmacy

 
Study Protocol and Statistical Analysis Plan 
ClinicalTrials.gov Identifier: NCT05744856 
Date: 16 January 2023 
Study Title: A Co-created Self-care and Informal Support Intervention Study 
Among Women With GDM in Vietnam 
 
1. Background and Rationale 
Gestational diabetes mellitus (GDM) is a common metabolic disorder of 
pregnancy and is associated with significant short- and long-term risks for both 
mother and child. In Vietnam, the prevalence of GDM has increased substantially 
in recent years, while systematic screening, counselling uptake, and long-term 
self-management support remain limited. Although pharmacological treatment 
is available for severe cases, most women rely heavily on lifestyle modification, 
informal family support, and self-care practices for disease management. 
Previous international studies indicate that self-care and social support 
interventions may improve quality of life, self-efficacy, and selected maternal and 
neonatal outcomes among women with GDM. However, such interventions are 
highly context-dependent, shaped by social norms, family structures, and health 
system capacity. To date, no structured self-care or informal support intervention 
for GDM has been developed or evaluated in the Vietnamese context. 
The VALID-II study was therefore designed as a feasibility intervention study, with 
the primary purpose of determining whether a co-created self-care and informal 
support intervention can be implemented, accepted, and retained among 
women with GDM in northern Vietnam. The study is intentionally positioned as 
a preparatory step prior to a future randomized controlled trial and is embedded 

within a larger observational cohort to allow simultaneous collection of maternal 
and neonatal outcome data . 
 
2. Study Objectives 
The primary objective of VALID-II is to evaluate the feasibility of a co-created self-
care and informal support intervention for women diagnosed with GDM. 
Feasibility is defined as the extent to which the intervention can be successfully 
delivered and maintained under real-world conditions and is assessed through 
recruitment, retention, and acceptability. 
Secondary objectives are exploratory and aim to assess the potential effects of 
the intervention on selected maternal and neonatal health outcomes, including 
self-care agency, perceived social support, breastfeeding practices, pregnancy 
outcomes, and neonatal morbidity. These analyses are intended to generate 
preliminary estimates of effect size and variance to inform the design of a future 
definitive trial. 
 
3. Study Design 
VALID-II is a two-arm, non-randomised feasibility intervention study with a 
delayed intervention design. The study is conducted in two sequential phases 
rather than in parallel. 
In the first phase, women diagnosed with GDM are allocated to a control group 
and receive standard care. During this phase, a subgroup of women and their 
informal support persons participate in an embedded ethnographic study. 
Findings from this qualitative work inform the co-creation of the intervention. 

In the second phase, after a delay of approximately three months, a new group 
of women diagnosed with GDM is allocated to the intervention arm and receives 
the co-created intervention in addition to standard care. This delayed design was 
chosen to allow meaningful intervention development grounded in participants’ 
lived experiences and to ensure cultural relevance. 
 
4. Study Setting 
The study is conducted in Thai Binh Province, northern Vietnam. Participants are 
recruited from two health facilities: Thai Binh Maternity Hospital, a public 
hospital providing antenatal care and delivery services, and Kim Ngan Clinic, a 
private clinic providing antenatal care only. Both facilities serve urban and peri-
urban populations and routinely perform oral glucose tolerance testing during 
pregnancy. 
 
5. Study Population 
Pregnant women attending antenatal care at the study sites are eligible for 
screening. Women are eligible for inclusion if they are ≤28 weeks’ gestation at 
enrolment, reside in Thai Binh Province, are able to read and speak Vietnamese, 
and provide written informed consent. Both singleton and multiple pregnancies 
are eligible, and a history of GDM in a prior pregnancy does not preclude 
participation. 
Women are excluded if they have known pregestational diabetes (type 1 or type 
2) or severe chronic disease that would substantially interfere with pregnancy 
management or study participation. 
 

6. Recruitment and Study Procedures 
At the first antenatal care visit, eligible women are informed about the study by 
trained study nurses or midwives. After providing written informed consent, 
participants complete a baseline questionnaire and are scheduled for a standard 
75-g oral glucose tolerance test (OGTT) at gestational age 24–28 weeks. 
OGTT procedures follow WHO and IADPSG diagnostic criteria. Women diagnosed 
with GDM are invited to participate in follow-up data collection and allocated to 
either the control or intervention group depending on study phase. Women 
without GDM continue routine care but contribute delivery and neonatal 
outcome data via medical records. 
Women diagnosed with GDM complete additional questionnaires during 
pregnancy (32–40 weeks gestation) and at 8–12 weeks postpartum. Delivery and 
neonatal outcomes are abstracted from medical records. 
 
7. Intervention and Comparator 
All women diagnosed with GDM receive standard care, which includes referral 
for counselling regarding diet, physical activity, and glucose monitoring. Because 
prior research indicated variable uptake of counselling, an ethical safeguard 
phone call is conducted by an endocrinologist to ensure that all women receive 
at least basic information about GDM self-care. 
The intervention arm receives, in addition to standard care, a co-created self-care 
and informal support intervention. The intervention includes written educational 
materials, digital communication, peer networking, and guidance for involving 
family members in daily self-care practices. The precise content and delivery 
format are determined through an iterative co-creation process involving women 
with GDM, their informal support persons, and local healthcare staff. 

 
8. Outcome Measures 
The primary outcomes relate to feasibility: 
• Recruitment is defined as the proportion of eligible women who consent 
to participate. 
• Retention is defined as the proportion of enrolled women who complete 
delivery and postpartum follow-up. 
• Acceptability is assessed using both quantitative Likert-scale measures and 
qualitative ethnographic interviews. 
Secondary outcomes include maternal outcomes (e.g., self-care agency, 
perceived social support, gestational weight gain, HbA1c, breastfeeding 
practices, postpartum depression) and neonatal outcomes (e.g., birth weight, 
gestational age, large for gestational age, macrosomia, neonatal hypoglycaemia). 
All outcomes and measurement tools are predefined and aligned with the 
published protocol . 
 
9. Statistical Analysis Plan (SAP) 
9.1 General Analytical Principles 
This Statistical Analysis Plan is finalised prior to completion of data collection for 
the intervention group. Analyses will be conducted according to the intention-
to-treat principle, whereby all participants are analysed in the group to which 
they were allocated based on study phase, regardless of intervention adherence. 
Given the feasibility nature of the study, analyses are primarily descriptive and 
exploratory. Formal hypothesis testing is not the primary objective. All statistical 
tests, where performed, will be two-sided with a nominal significance level of 

0.05. Emphasis will be placed on estimation, confidence intervals, and clinical 
plausibility rather than statistical significance alone. 
9.2 Analysis of Feasibility Outcomes 
Recruitment will be calculated as the proportion of eligible women diagnosed 
with GDM who consent to participate in the study. Retention will be calculated 
as the proportion of enrolled women who provide delivery data and complete 
the postpartum questionnaire. Both outcomes will be presented as percentages 
with corresponding 95% confidence intervals. 
Acceptability will be analysed using a mixed-methods approach. Quantitative 
acceptability scores will be summarised using means, standard deviations, 
medians, and ranges. The predefined progression criterion is a mean Likert score 
greater than 3. Qualitative data from ethnographic interviews will be analysed 
thematically to explore participants’ experiences, perceived usefulness, and 
barriers to engagement with the intervention. 
9.3 Analysis of Secondary Outcomes 
Secondary maternal and neonatal outcomes will be analysed descriptively and 
exploratorily. Continuous variables (e.g., birth weight, gestational age, self-care 
agency scores) will be summarised using means and standard deviations or 
medians and interquartile ranges, depending on distribution. Binary outcomes 
(e.g., large for gestational age, preterm birth) will be summarised as proportions. 
For exploratory comparisons between intervention and control groups, 
regression models will be used where appropriate. Logistic regression will be 
applied to binary outcomes, and linear regression to continuous outcomes. Effect 
estimates will be presented as odds ratios or mean differences with 95% 
confidence intervals. No adjustment for multiple comparisons will be performed. 
9.4 Adjustment for Confounding 

Because the study uses a non-randomised design, baseline characteristics will be 
examined for imbalance between groups. If clinically relevant imbalances are 
observed, adjusted analyses will be conducted including key covariates such as 
maternal age, body mass index, parity, and gestational age at diagnosis. Adjusted 
analyses are considered exploratory and intended to inform future trial design 
rather than establish causal inference. 
9.5 Missing Data 
The extent and patterns of missing data will be described for all outcomes. Given 
the feasibility focus of the study, no formal imputation of missing data is planned. 
Analyses will be based on available data, and the potential impact of missingness 
will be discussed qualitatively. 
9.6 Qualitative Data Analysis 
Qualitative data from ethnographic interviews and fieldnotes will be transcribed 
verbatim and analysed using a content analysis approach. Coding will be 
performed iteratively, and themes related to feasibility, acceptability, self-care 
practices, and informal support will be identified. Qualitative findings will be 
used to contextualise quantitative results rather than to generate statistically 
generalisable conclusions. 
 
10. Data Management 
All quantitative data are collected and stored using REDCap on secure servers at 
Thai Binh University of Medicine and Pharmacy. Data exports for analysis will be 
performed using Stata, SPSS, or R. Access to identifiable data is restricted to 
authorised study personnel. 
 

11. Ethics and Trial Status 
The study has received ethical approval from the Ethics Council in Biomedical 
Research in Thai Binh (IRB – VN01.009). All participants provide written informed 
consent prior to participation. The trial is registered at ClinicalTrials.gov 
(NCT05744856) and is currently ongoing.