Denmark Study: Do Insulin Pumps Protect Your Eyes Better Than Daily Injections?

A study from Denmark offers an important look at one of the most pressing questions for people living with type 1 diabetes: does switching to an insulin pump (also called continuous subcutaneous insulin infusion, or CSII) better protect your eyes from diabetes-related damage compared to taking multiple daily injections (MDI)?

Researchers at Odense University Hospital, one of Denmark's leading academic medical centers, used the country's national diabetic retinopathy registry — a comprehensive, population-wide database — to answer this question with a level of data scale and quality rarely available in the United States.

What the Researchers Did

The Danish team analyzed records from 2013 to 2022, enrolling 674 insulin pump users and carefully matching them with 2,006 people using multiple daily injections. Patients were matched by age, sex, and existing eye disease severity to ensure a fair comparison. The average participant was 36 years old, just over half were female, and they were followed for an average of nearly five years.

What They Found

The headline finding: insulin pump therapy did not significantly reduce the overall risk of diabetic retinopathy (DR) getting worse compared to multiple daily injections. Statistically, the hazard ratio was 1.05 — essentially no meaningful difference between the two groups.

However, there was one notable finding that deserves attention. People using insulin pumps had a 2.4 times higher likelihood of needing focal laser photocoagulation — a targeted eye procedure used to treat abnormal blood vessel growth. Researchers caution this finding may reflect the fact that pump users in the study already had more complex diabetes management needs, rather than pumps causing eye damage directly.

Why This Matters for US Patients

In the United States, insulin pump use has grown significantly. The American Diabetes Association (ADA) currently supports CSII as a valid and effective delivery method for insulin, particularly for people with type 1 diabetes who struggle to achieve blood sugar targets with injections alone. Many US patients and physicians choose pumps with the expectation of broader health benefits beyond blood sugar control.

This Danish study — backed by a truly national dataset — suggests that when it comes to protecting your eyes specifically, the delivery method may matter less than overall blood sugar control. The ADA recommends keeping HbA1c below 7% (average blood sugar of approximately 154 mg/dL) to minimize retinopathy risk, a target achievable with both pumps and injections.

Denmark's universal healthcare system allowed researchers to track an entire national population over nearly a decade — something extremely difficult to replicate in the fragmented US healthcare system. That makes these findings particularly credible and relevant.

What You Should Take Away

• Insulin pumps are not automatically superior to daily injections for protecting your eyes.
• Blood sugar control quality — not delivery method — remains the primary driver of retinopathy risk.
• Annual dilated eye exams remain essential regardless of which insulin method you use.
• Talk to your endocrinologist if you're considering switching delivery methods based on eye health concerns alone.

About the Study

Authors: Thykjær, Rosengaard, Andersen
Institution: Department of Ophthalmology, Odense University Hospital; Steno Diabetes Center Odense, University of Southern Denmark
Journal: Journal of Diabetes and Its Complications, 2024
PMID: 39096767 | DOI: 10.1016/j.jdiacomp.2024.108830