South Korean Trial Finds Tubeless Automated Insulin Delivery Outperforms Sensor-Augmented Pumps in Type 1 Diabetes

A study from South Korea offers compelling evidence that tubeless, on-body automated insulin delivery (AID) systems provide meaningfully better blood sugar control than tubeless sensor-augmented pumps (SAP) for adults living with type 1 diabetes — and the findings carry important implications for patients in the United States.

What the Researchers Did

Scientists at Samsung Medical Center and Sungkyunkwan University School of Medicine in Seoul led a large, multicentre randomised controlled trial across 13 tertiary hospitals throughout South Korea. A total of 104 adults between the ages of 19 and 69 with type 1 diabetes — all with HbA1c levels below 10.0% — were randomly assigned to use either a tubeless AID system or a tubeless SAP for 12 weeks. The key difference: an AID system automatically adjusts insulin delivery based on real-time continuous glucose monitor (CGM) readings, while a SAP displays CGM data but still requires the patient to manually adjust dosing.

What They Found

The primary goal was improving Time in Range (TIR) — the percentage of each day that blood glucose stays between 70–180 mg/dL (converted from 3.9–10.0 mmol/L), the internationally recognised healthy target range.

• AID group: TIR improved from 62.1% at baseline to 71.5% after 12 weeks
• SAP group: TIR improved only modestly, from 64.7% to 66.9%
• The adjusted difference between groups was a statistically significant 6.5 percentage points (p<0.001)

The AID group also showed significant improvements in time below range (hypoglycaemia), time above range (hyperglycaemia), glucose variability (CV), and mean glucose levels. HbA1c fell from approximately 6.8% to 6.4% in the AID group and from 6.6% to 6.3% in the SAP group — a difference that was not statistically significant between groups. Critically, no episodes of diabetic ketoacidosis or severe hypoglycaemia occurred in either group.

Why an International Perspective Matters

South Korea has rapidly expanded its diabetes technology infrastructure and maintains rigorous clinical trial standards comparable to US and European benchmarks. This 13-centre trial reflects real-world use across diverse clinical settings — not just elite research hospitals — making the results more broadly applicable. Because this research was conducted independently of US device manufacturers, it provides an unbiased, externally validated data point on AID technology performance.

How This Compares to US Guidelines

The American Diabetes Association (ADA) currently recommends a TIR goal of greater than 70% for most adults with type 1 diabetes. The AID group in this study crossed that threshold (71.5%), while the SAP group did not (66.9%). The ADA also endorses automated insulin delivery systems as preferred technology when available and accessible — findings from South Korea reinforce that recommendation with robust randomised trial evidence.

Why This Matters for US Patients

Tubeless, on-body AID systems — such as those without traditional tubing connecting pump to body — are gaining traction in the US market. This South Korean trial provides strong randomised evidence that the automation advantage is real and clinically meaningful: nearly 5 extra hours per day in healthy blood sugar range compared to a sensor-augmented pump. For US patients weighing an upgrade from a SAP to a fully automated system, or discussing device options with their endocrinologist, this international data adds weight to that conversation. The absence of serious adverse events also reinforces the safety profile of these newer systems.

Original Study: Kim, Jin, Kang et al. "Comparison between a tubeless, on-body automated insulin delivery system and a tubeless, on-body sensor-augmented pump in type 1 diabetes: a multicentre randomised controlled trial." Diabetologia (2024). DOI: 10.1007/s00125-024-06155-y | PMID: 38634887