Overnight closed-loop insulin delivery in young people with type 1 diabetes: a free-living, randomized clinical trial.
OBJECTIVE
To evaluate feasibility, safety, and efficacy of overnight closed-loop insulin delivery in free-living youth with type 1 diabetes.


METHODS
Overnight closed loop was evaluated at home by 16 pump-treated adolescents with type 1 diabetes aged 12-18 years. Over a 3-week period, overnight insulin delivery was directed by a closed-loop system, and on another 3-week period sensor-augmented therapy was applied. The order of interventions was random. The primary end point was time when adjusted sensor glucose was between 3.9 and 8.0 mmol/L from 2300 to 0700 h.


RESULTS
Closed loop was constantly applied over at least 4 h on 269 nights (80%); sensor data were collected over at least 4 h on 282 control nights (84%). Closed loop increased time spent with glucose in target by a median 15% (interquartile range -9 to 43; P < 0.001). Mean overnight glucose was reduced by a mean 14 (SD 58) mg/dL (P < 0.001). Time when glucose was <70 mg/dL was low in both groups, but nights with glucose <63 mg/dL for at least 20 min were less frequent during closed loop (10 vs. 17%; P = 0.01). Despite lower total daily insulin doses by a median 2.3 (interquartile range -4.7 to 9.3) units (P = 0.009), overall 24-h glucose was reduced by a mean 9 (SD 41) mg/dL (P = 0.006) during closed loop.


CONCLUSIONS
Unsupervised home use of overnight closed loop in adolescents with type 1 diabetes is safe and feasible. Glucose control was improved during the day and night with fewer episodes of nocturnal hypoglycemia.
Corresponding author: Roman Hovorka, rh347@cam.ac.uk.
Roman
R
Hovorka
Daniela
D
Elleri
Hood
H
Thabit
Janet M
JM
Allen
Lalantha
L
Leelarathna
Ranna
R
El-Khairi
Kavita
K
Kumareswaran
Karen
K
Caldwell
Peter
P
Calhoun
Craig
C
Kollman
Helen R
HR
Murphy
Carlo L
CL
Acerini
Malgorzata E
ME
Wilinska
Marianna
M
Nodale
David B
DB
Dunger
D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism*; D002648:Child; D002940:Circadian Rhythm; D018592:Cross-Over Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000188:drug therapy*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000517:prevention & control; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D007328:Insulin / Q000008:administration & dosage* / Q000627:therapeutic use*; D007332:Insulin Infusion Systems / Q000009:adverse effects; D008297:Male; D013997:Time Factors; D016896:Treatment Outcome
D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin