Background: This prerandomization analysis from the Australian HCL-Adult trial (registration number: ACTRN12617000520336) compared masked continuous glucose monitoring (CGM) metrics among adults using insulin pumps versus multiple daily injections (MDIs), who were all self-monitoring blood glucose (SMBG). Methods: Adults with type 1 diabetes, using an insulin pump or MDIs without real-time CGM (and entering a trial of closed-loop technology), were eligible. MDI users were given an insulin dosage calculator. All participants received diabetes and carbohydrate-counting education, then wore masked CGM sensors for 3 weeks. Ethics Approval: HREC-D 088/16 Results: Adults using MDIs (n = 61) versus pump (n = 59) did not differ by age, sex, diabetes duration, insulin total daily dose, or HbA1c at baseline. After education, median (interquartile range) CGM time in range (TIR) 70-180 mg/dL (3.9-10.0 mmol/L) was 54% (47, 62) for those using MDIs and 56% (48, 66) for those using pump (P = 0.40). All CGM metrics were equivalent for 24 h/day for MDI and pump users. Overnight, those using MDIs (vs. pump) spent more time with glucose <54 mg/dL (<3.0 mmol/L): 1.4% (0.1, 5.1) versus 0.5% (0.0, 2.0), respectively (P = 0.012). They also had more CGM hypoglycemia episodes (121 vs. 54, respectively; incidence rate ratio [95% confidence interval] 2.48 [1.51, 4.06]; P < 0.001). Conclusions: Adults with type 1 diabetes using pumps versus MDIs in conjunction with SMBG experienced less nocturnal hypoglycemia, measured by masked CGM, after equivalent diabetes and dietary education in conjunction with insulin dosage calculator provision to all. However, both groups had equivalent TIR. This observation may reflect advantages afforded by flexibility in basal insulin delivery provided by pumps.
Keywords: Blood glucose self-monitoring; Humans; Insulin pumps; Time in range; Type 1 diabetes.