PurposeGeriatric diabetes is complicated by the frailty of this population, and hypoglycemia with insulin is not uncommon in these patients. Automated Insulin Delivery (AID) systems may provide better glycemic control in elderly patients with brittle type 2 diabetes. MethodsThirty-four patients (≥ 60 years) including cancer patients with brittle diabetes were switched to an AID system from multiple-dose insulin (MDI) treatment. HbA1c level, weight, total daily insulin requirement, and C-peptide, creatinine, and lipids were followed for at least six months. ResultsThere were 34 patients (14 male, 41.2 %) with a median age of 67 (IQR 63.0–75.5). Six patients (17.6 %) were on chemotherapy and/or steroids (Ch/S). The patients’ initial median HbA1c % was 9.3 (IQR 7.6–11.0), c-peptide level was 0.9 (IQR 0.5–2.2) ng/mL, and median total daily insulin dose was 41 IU (IQR 32–53).Six months after the patients were switched to an AID system their HbA1c % decreased to 7.1 (IQR 6.5–8.1), p < 0.001 and c-peptide increased to 1.21 (IQR 0.2–1.7) ng/mL, p = 0.878. Total insulin dose decreased with AID systems [32 IU (IQR 23.9–37.8)), p < 0.001].There was a decrease in median HbA1c % in patients on Ch/S [8.7 (IQR 7.0–11.5) to 6.9 (IQR 6.3–9.2)] however it didn’t reach statistical significance p = 0.225. Total insulin dose also decreased without statistical significance [33 IU (IQR 41–28) to 28 (IQR 23–35), p = 0.173].The mean time in range (TIR) percent of the patients with AID systems were as follows; <54 mg/dL was 0.5 %, 56–70 mg/dL was 1.3 %, 70–180 mg/dL was 64.8 %, >180 mg/dL was 26.7 % and > 250 mg/dL was 6.7 %. ConclusionAlthough AID systems are tested mostly in young type 1 patients our results show that elderly patients with brittle type 2 diabetes also benefit from an AID system. Even in very frail patients such as cancer patients, improvement can be seen.