Background: Using a software, which creates a closed loop between the pump and the monitoring glucose sensor is considered to be a progress in controlling and using insulin pumps in type 1 diabetes patients (T1DM). OpenAPS is a system which completes and closes the pump-glucose sensor loop.

Aim: The aim of this study is to examine the effect of an independent closed-loop insulin system using the OpenAPS system on the glycemic control of T1DM patients.

Material and Methods: 24 T1DM patients with insulin pump were included in the study. 11 started using the OpenAPS closed-loop system and 13 continued using an insulin pump without OpenAPS. The effect on glycemic control (HbA1c, Fasting Blood Glucose (FBG), pre-meal, post-meal and before bedtime glucose) was recorded before the beginning of the study and on 12±1 and 24±1 weeks. Hypoglycemic episodes were also recorded.

Results: Patients using OpenAPS noted a significant reduction of HbA1c on the 3 and 6-month follow-up (7.70±1.14 vs. 6.85±1.17 vs. 6.63±1.05, p<0.001). The reduction of HbA1c in the other group ws not significant (7.78±1.12 vs. 7.44±1.18 vs. 7.21±1.09, p=0.058). A significant reduction on FBG was noticed on the OpenAPS group (154.14±26.17 vs. 128.33±21.41 vs. 117.74±8.73, p=0.010), while the other group’s reduction was not found to be statistically significant (p= 0.112). Statistically lower pre-meal (p< 0.001), post-meal (p< 0.001) and before bedtime (p= 0.016) blood glucose levels were found on the OpenAPS group. Before the beginning of the study all of the participants had at least one hypoglycemic episode in the last month, while after 3 months of using OpenAPS, no patient showed hypoglycemia. The other group’s participants continued having such episodes.

Conclusions: Using a closed-loop in an insulin pump via OpenAPS system leads to a better glycemic control, less hypoglycemic episodes and lower daily blood glucose levels fluctuations compared to using an insulin pump with no closed-loop system.


A. Koutsovasilis: None. A. Sotiropoulos: None. A. Antoniou: None. V. Kordinas: None. D. Papadaki: None. T. Peppas: None.

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