Adults with type 1 diabetes switched to an extended infusion set and kept its catheter in place for an average of 6.1 days at six months, compared with 3.6 days at baseline. The prospective, non-randomized study included 65 people using the MiniMed 780G automated insulin-delivery system and Guardian 4 continuous glucose monitor.
That longer average did not mean everyone reached seven days. At six months, 92.3% were still using the extended set, but 48.3% had maintained the full seven-day duration. The mean interval between reservoir changes also rose from 3.5 to 5.2 days.
The practical change extended beyond the catheter
Total daily insulin use, including basal and bolus doses, stayed stable. Yet the study estimated that 1,500 IU covered an average of 26.1 days after the transition, compared with 18.4 days at baseline. The reported p-value for that coverage comparison was below 0.001.
Catheter and reservoir timing also moved together. At six months, longer cannula wear was positively correlated with a longer reservoir-change interval, with a Pearson correlation of 0.712 and a reported p-value below 0.001. That is an association within the cohort, not evidence that extending one interval caused the other.
Glucose measures moved in different directions
The glucose picture was less straightforward. HbA1c, a longer-term blood-sugar measure, fell from 6.8% to 6.4% at six months, but mean glucose rose from 141.7 to 145.3 mg/dL. Time in range, the share of readings in the target range, fell from 80.0% to 78.0%, while time above 180 mg/dL rose from 15.0% to 17.0%.
The paper also reported that TiTR, another glucose-range measure, fell from 54.0% to 52.0%, while time above 250 mg/dL rose from 2.4% to 3.5%. Measures of glucose variability and time below range remained stable. The authors described overall glycemic control as stable despite these modest shifts.
No participant experienced severe hypoglycemia or diabetic ketoacidosis requiring hospital admission after switching, and no adverse-event category changed significantly over time. Those zero-event findings describe what was observed during follow-up; they do not establish zero risk.
Participants also reported better tolerability and satisfaction. At six months, cannula-insertion pain fell from 2.1 to 1.2 points on the reported scale, infusion-set satisfaction rose from 8.2 to 9.0, and the satisfaction subscale of the EsDQoL quality-of-life measure improved from 30.4 to 27.9. All three changes were statistically significant in the reported analyses.
What the comparison can and cannot show
The comparison was made within the same participants, who served as their own controls, rather than against a randomized parallel group. Eligible adults had at least 12 months of automatic-mode experience and had been using a straight 6-mm or 9-mm catheter for up to three days. A structured education program covered set replacement and the management of hypoglycemia, hyperglycemia and ketosis.
That design can show what changed in this group, but it cannot establish that the extended set caused the longer wear, the HbA1c change or the higher satisfaction. Seven of the 65 participants discontinued before month six: four because of adverse events and three because they were lost to follow-up. Fifty-eight completed follow-up.
Follow-up included a telephone contact at one month and in-person visits at three and six months. Because the study involved adults using the MiniMed 780G and Guardian 4 system, its results do not establish whether the same pattern would hold for children, people using other automated insulin-delivery systems or longer-term use. Open-access funding came from FEDER European Funds and the Junta de Castilla y León; the authors reported no support from Medtronic/Minimed or any other external source.
For this group, the study points to a trade-off rather than a universal seven-day solution: average catheter wear and reservoir intervals were longer, but fewer than half maintained the intended duration.
Paper data and sources
Original title: Real-World safety, patient-reported outcomes, and glycemic metrics with a 7-Day extended infusion set in adults with Type 1 diabetes using automated insulin delivery systems.
Authors: María de la O Nieto de la Marca, Pablo Fernández Velasco, Sofía Del Amo Simón et al.
Journal/Repository: Endocrine
Status: Corrected publication
First online: 2026-08-21
DOI: 10.1007/s12020-026-04743-z
Original paper · Full text