Background: Real-time continuous glucose monitoring (rtCGM) improves glycemic control in type 1 diabetes (T1D) patients treated with continuous subcutaneous insulin infusion (CSII). However, the benefits of rtCGM in T1D patients treated with multiple daily insulin injection (MDI) therapy has not been well studied. We explored the effects of rtCGM versus self-monitoring of blood glucose (SMBG) on clinical outcomes within a large T1D population treated with either CSII or MDI therapy.
Methods: This retrospective, longitudinal analysis utilized datasets from T1D patients enrolled in a commercial health plan to assess changes in HbA1c in 187 naïve to rtCGM users and 6260 SMBG users. Propensity score modeling was used to assess inpatient admissions, emergency room (ER) visits in 1130 patients (565 rtCGM, 565 SMBG). Differences in HbA1c reduction (rtCGM+MDI vs rtCGM+CSII) were evaluated.
Results: Larger, clinically meaningful HbA1c reductions were seen among rtCGM versus SMBG users: -0.5% ( P = .004) versus -0.2% ( P < .0001); 0.3% diff in diff, P = .03. All-cause inpatient admissions were lower for rtCGM users: -42%, P = .013. Emergency room visits coded for diabetic ketoacidosis (DKA) were four times higher for SMBG patients than rtCGM patients: 17 versus 4, P = .0318. HbA1c reductions were most notable with rtCGM+MDI versus rtCGM+CSII treatment: -0.6% ( P = .01) versus -0.3% ( P = .16).
Conclusions: Use of rtCGM in T1D patients facilitates greater HbA1c improvements and reduced health care system utilization compared with traditional SMBG use regardless of insulin administration method. Treatment with rtCGM in conjunction with MDI confers similar or greater glycemic benefits without the additional costs associated with CSII therapy.
Keywords: CSII; SMBG; continuous glucose monitoring; insulin pump; rtCGM; type 1 diabetes.