evidence: Compared with the control period, day-and-night closed-loop insulin delivery reduced the proportion of time with glucose concentration below 3·9 mmol/L by 50% (37–59, p<0·0001), below 3·5 mmol/L by 65% (53–74, p<0·0001), below 3·3 mmol/L by 70% (57–78, p<0·0001), and below 2·8 mmol/L by 76% (59–86, p<0·0001), as well as the burden of hypoglycaemia (ie, area under the curve when sensor glucose concentration was less than 3·5 mmol/L) by 73% (59–82, p<0·0001). Closed-loop insulin delivery also reduced the number of nights when glucose concentration was below 3·5 mmol/L for at least 20 min as well as the mean duration of such periods (table 2). Compared with usual pump therapy, closed-loop insulin delivery reduced the proportion of time with glucose concentration above the target range (ie, >10 mmol/L) by 6·9 percentage points (3·5–10·2, p=0·0003), above 13·9 mmol/L by 3·0 percentage points (1·6–4·4, p=0·0002) and above 16·7 mmol/L by 1·2 percentage points (0·6–1·9, p=0·0009; table 2). Moreover, all measures of glycaemic variability were significantly lower in the closed-loop period than in the control period: SD of sensor glucose was 0·5 mmol/L (0·3–0·7) lower (p<0·0001), coefficient of variation of sensor glucose within days was 5·0% (3·0–7·1) lower (p<0·0001), and coefficient of variation of sensor glucose between days was 7·5% (5·3–9·7) lower (p<0·0001; table 2). Total daily insulin was similar between study periods (table 3). Weekly trends in glucose control and insulin delivery are shown in the appendix (p 3).
intervention: day-and-night closed-loop insulin
comparator: usual pump therapy
outcome: glucose control