ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2019) 66 OC3.2 | DOI: 10.1530/endoabs.66.OC3.2

2 year experience of 'Do-It-Yourself ' Hybrid Closed Loop in an adolescent with Type 1 Diabetes

Shankar Kanumakala1 & Peter Lynton2


1Brighton & Sussex University Hospitals NHS Trust, Brighton, UK; 2Parent, Brighton, UK


Introduction: The use of Closed Loop (CL) system has slowly progressed from using a short time overnight to prolonged periods under everyday living conditions. In the last few years, Do-It-Yourself Closed Loop (DIY-CL) technology has become openly available as part of ‘patient-led’ global initiative (#Wearenotwaiting) outside the conventional regulatory pathways, raising many medico-legal and ethical dilemmas.

Methods: Majority of the DIY-CL users are adults; we describe using this new technology as a ‘parent-led’ initiative for 2 years in an adolescent. Type 1 diabetes (T1D) was diagnosed at 3.5 years in 2008; Islet Cell antibodies were positive at diagnosis; and patient’s father was known to have T1D too.

Results:

Time PeriodAge (Years)Insulin Regimen*Average Insulin dose (units/kg per day)Mean HbA1c (mmol/mol) (%)
2009–20104–5BD0.7866 (8.2%)
2011–166–11CSII0.8254 (7.1%)
201712CSII + CGM0.7955 (7.2%)
2018–201913–14DIY-CL1.0341 (5.9%)
*BD – Twice daily insulin injections; CSII – Continuous Subcutaneous Insulin Infusion; CGM – Continuous Glucose Monitoring

Time PeriodAge (Years)Insulin Regimen*Average Insulin dose (units/kg per day)Mean HbA1c (mmol/mol) (%)
2009–20104–5BD0.7866 (8.2%)
2011–166–11CSII0.8254 (7.1%)
201712CSII + CGM0.7955 (7.2%)
2018–201913–14DIY-CL1.0341 (5.9%)

CGM sensor data capture over 90 days in Apr–Jun 2019 was 97.2%; lost readings were mainly due to sensor warm up.

Parents reported numerous advantages (improved sleep & quality of life; no fear of hypoglycaemia; decreased diabetes care burden) and broadly no disadvantages, but high costs if not funded. Adolescent reported many advantages (100% school attendance; easy to check if system not working, less obvious than pump and no huge effect on sugar levels if a bolus dose is missed!) and no disadvantages.

DescriptionGlucose Value (mmol/l)Number of readings% of time
Euglycaemia4–1022 81992.4%
Level 1 Hypoglycaemia3–3.96832.8%
Level 2 Hypoglycaemia<2.91420.6%
Level 1 Hyperglycaemia10.1–13.910034.0%
Level 2 Hyperglycaemia>13.9590.2%

Conclusions: DIY–CL system appears safe and effective in reducing hypoglycaemia, minimising hyperglycaemia and achieving good HbA1c consistently over 2 years, even during adolescence. It improved quality of life for patient & family and decreased diabetes burden for them. Many ethical dilemmas, especially the non-regulated off-license use of this technology, still persist.

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