Eye blood vessel changes when type 2 diabetes medicines are started
Observes eye blood vessels in adults starting diabetes medicines.
Key facts
- Who runs it
- Thammasat University Hospital
- Where
- Pathum Thani, ThailandSee the site
- Trial code
- Registry title
- Glycemic Velocity and Early Retinal Microvascular Change With GLP-1RA Versus SGLT2i Initiation in Type 2 Diabetes (GLIDE)
- Status
- Not yet recruiting
- People taking part
- 126 people, planned
- Started
- 1 Sept 2026
- Expected to end
- 1 Sept 2027
- Type of study
- Observational, 2 groups
- Treatments tested
- GLP-1 Receptor Agonists
- SGLT2 inhibitor
- Record updated
- 31 August 2026
Who can take part
AI summary
From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.
The trial is looking for adults with type 2 diabetes whose doctor has decided to start a GLP-1 receptor agonist or an SGLT2 inhibitor for the first time. They must have no diabetic retinopathy or only mild early disease.
- Age
- 18 years or older
- Sex
- All sexes
- Disease stage
- Type 2 diabetes with no diabetic retinopathy, or mild non-proliferative diabetic retinopathy in the study eye(s)
- Earlier treatment
- Must be starting a first-ever GLP-1 receptor agonist or a first-ever SGLT2 inhibitor. No earlier laser, anti-VEGF or corticosteroid injections, or eye surgery for diabetic retinopathy or maculopathy.
- Biomarker or test result
- HbA1c high enough to allow a measurable change (for example 7.0% (53 mmol/mol) or higher), taken within 30 days before or after the eye assessment
Main reasons for not taking part
- Moderate-to-severe or proliferative diabetic retinopathy, or diabetic macular edema involving the center of the retina
- Any earlier use of a GLP-1 receptor agonist or SGLT2 inhibitor
- Type 1 diabetes, latent autoimmune diabetes of adults, or secondary diabetes
- Other eye disease that could affect the measurements, such as age-related macular degeneration, uveitis, high myopia or glaucoma
- Pregnancy
The registry criteria, word for word
Show all 16 criteriaShow less
Who can take part
- Adults aged 18 years or older with a documented diagnosis of type 2 diabetes mellitus
- Clinical decision, made by the treating physician independently of the study, to initiate a first-ever GLP-1 receptor agonist or a first-ever SGLT2 inhibitor
- Baseline retinal status ranging from no diabetic retinopathy to mild non-proliferative diabetic retinopathy (NPDR) in the study eye(s), confirmed by fundus photography / ETDRS grading
- Baseline HbA1c within a range permitting a measurable subsequent change (e.g., 7.0% or higher), obtained within 30 days before or after the scheduled ophthalmic assessment
- Media sufficiently clear and fixation adequate to obtain gradable OCT-A and OCT images
- Able and willing to provide written informed consent and to attend scheduled follow-up visits
Who cannot take part
- Prior or concurrent treatment for diabetic retinopathy or maculopathy: pan-retinal or focal/grid laser photocoagulation, intravitreal anti-VEGF or corticosteroid therapy, or vitreoretinal surgery
- Any prior exposure to a GLP-1 receptor agonist or SGLT2 inhibitor (to preserve the new-user design)
- Recent (within 3 months) intraocular surgery in the study eye, including cataract surgery
- Type 1 diabetes, latent autoimmune diabetes of adults, or secondary diabetes
- Uncontrolled systemic hypertension or a known systemic condition (e.g., significant anemia, severe renal impairment with eGFR < 30 mL/min/1.73 m², or active malignancy) that independently affects retinal perfusion or oximetry, at investigator discretion
- Pregnancy, or planned simultaneous initiation of insulin such that the index glucose-lowering exposure cannot be attributed (concurrent stable insulin is permitted and recorded as a pre-specified effect modifier)
- Other retinal or choroidal disease that would confound microvascular/choroidal measurement: age-related macular degeneration, retinal vein or artery occlusion, uveitis, high myopia (spherical equivalent more negative than -6.0 D or axial length greater than 26.0 mm), or significant media opacity precluding imaging
- Moderate-to-severe NPDR, proliferative diabetic retinopathy, or center-involving diabetic macular edema at baseline
- Coexisting glaucoma or optic neuropathy that independently alters retinal vascular or neural metrics
- Inability to provide informed consent or to comply with the imaging and follow-up schedule
Where in Thailand
- Faculty of Medicine, Thammasat UniversityPathum Thani, ThailandContact: Wit Tharanon, Doctor of medicineNo longer taking part
About the trial
What the trial wants to find out
The GLIDE study looks at how the small blood vessels of the eye respond during the first months of a new diabetes medicine. Two widely used classes of glucose-lowering drugs, GLP-1 receptor agonists and SGLT2 inhibitors, are compared in adults with type 2 diabetes who have no diabetic retinopathy or only early (mild) diabetic retinopathy.
Read full original descriptionShow less
When blood sugar (HbA1c) falls quickly after starting treatment, the retina can undergo a brief, temporary worsening before it stabilizes and benefits over the long term. This study asks whether it is the speed of that blood-sugar reduction, which we call "glycemic velocity," rather than the specific drug, that drives early changes in retinal and choroidal blood flow.
Participants are patients whose own physician has decided, independently of the study, to start one of these two drugs for the first time. The study does not choose, provide, or change any medicine; it adds only eye imaging, blood tests, and observation. Each participant is followed with specialized, non-invasive eye scans, optical coherence tomography angiography (OCT-A) and structural/choroidal OCT, together with HbA1c and other measurements, at the start of treatment and again over the following months.
The main measurement is the change, from the start of treatment to month 3, in the density of the tiny deep-layer capillaries at the center of the retina, measured on OCT-A. The study will test whether faster HbA1c reduction is linked to greater early change in these vessels and, using statistical mediation analysis, will estimate how much of any difference between the two drug groups is explained by glycemic velocity versus a direct drug effect.
If glycemic velocity, a factor physicians can influence by adjusting how quickly treatment is intensified, turns out to drive early retinal change, the findings could guide safer treatment strategies and help identify patients who need closer eye monitoring when starting these medicines.
The 2 groups in the trial
- GLP-1 receptor agonist initiators
Adults with type 2 diabetes and no-to-mild NPDR who are starting a first-ever GLP-1 receptor agonist, prescribed by the treating physician independently of the study. Followed with the standardized multimodal retinal-imaging and metabolic battery. Primary exposure of interest, glycemic velocity, is measured within this cohort.
Treatment: GLP-1 Receptor Agonists
- SGLT2 inhibitor initiators
Adults with type 2 diabetes and no-to-mild NPDR who are starting a first-ever SGLT2 inhibitor, prescribed by the treating physician independently of the study. Active comparator that shares the glucose-lowering indication but is not classically associated with early retinopathy worsening. Followed with the identical battery.
Treatment: SGLT2 inhibitor
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Contact the study team: see the registry record → Contacts and Locations
Print a page for my doctorData and sources
- Registry record
- Listed on ClinicalTrials.gov.
- Official title
- Glycemic Velocity as a Modifiable Determinant of Early Retinal Microvascular and Choroidal Change During Initiation of GLP-1 Receptor Agonist Versus SGLT2 Inhibitor Therapy in Type 2 Diabetes: A Prospective Multimodal Retinal Imaging Cohort Study (the GLIDE Study)
- Plain-language title
- Eye blood vessel changes when type 2 diabetes medicines are startedGenerated from the registry record. The registry title is the official one.
- AI summary
- From the trial's eligibility criteria. Read by machine on 12 November 2026.
- Record updated
- 31 August 2026