Tirzepatide does not increase incident diabetic retinopathy in overweight Type 1 diabetes patients over one year
Background
Overweight and obesity are increasingly prevalent in adults with Type 1 Diabetes (T1D), exacerbating insulin resistance and increasing cardiometabolic burden. While tirzepatide, a dual GIP and GLP-1 receptor agonist, is approved for Type 2 Diabetes and obesity, its impact on diabetic retinopathy (DR), including diabetic macular edema (DME), in T1D patients remains largely unknown. This gap is critical given the high risk of microvascular complications in T1D and the growing off-label use of tirzepatide in this population.
Study Design
Researchers conducted a retrospective chart review of 106 overweight/obese adults with T1D receiving adjunctive tirzepatide continuously for at least 1 year ± 2 months. This 'cases' group was compared to 85 controls with T1D not using tirzepatide, matched by age, sex, and body mass index. Retinal eye examination results were collected at baseline and follow-up (ranging from 6-24 months). The primary endpoints were the incidence rates of DR and DME in individuals without baseline eye disease, and the progression or regression of existing DR/DME.
Key Findings
- Incident DR rates were similar between tirzepatide-treated T1D cases (25.6%) and controls (29.2%).
- Mean
HbA1csignificantly improved in tirzepatide cases within 6 months (P < 0.001), remaining stable thereafter. - Rapid
HbA1cdecline (≥0.5% within 6 months) was associated with higher incident DR (39.3% vs. 17.1%, P = 0.048). - Diabetic retinopathy remained stable for most individuals with baseline DR in both groups.
Why It Matters
This retrospective analysis offers reassuring preliminary data for Type 1 diabetes patients with overweight/obesity who are using tirzepatide off-label, suggesting it does not appear to increase the incidence or progression of diabetic retinopathy over one year. The finding that rapid HbA1c decline, regardless of tirzepatide use, is associated with higher incident DR is a critical practical takeaway. This reinforces the clinical guidance to achieve glycemic control gradually, especially in patients at risk for or with existing retinopathy. While promising, these results from a retrospective study highlight the need for randomized controlled trials to confirm these observations and establish definitive safety protocols for tirzepatide use in T1D.
tirzepatide
type 1 diabetes
diabetic retinopathy
obesity
glp-1 agonist
gip agonist