Effect of Continuous Glucose Monitoring on Glycemic Control in Adults Using Multiple Daily Insulin Injections

Clinical trials showing benefit of continuous glucose monitoring (CGM) have largely been conducted in insulin pump users. The DIaMonD study examined effectiveness of CGM in adults with T1D (n=158) or T2D (n=158) with elevated A1c using multiple daily injections (MDI). Subjects at 29 sites in the US and Canada were randomized to CGM or SMBG for 24 wks. Subjects were diverse but similar between the CGM (n=184) and SMBG (n=132) groups with respect to age (mean ±SD, 52±14 vs. 57±11 yr), baseline A1c (8.6+0.6 vs. 8.6+0.6%), DM duration (median [IQR], 17 [10–26] vs. 19 [12–25] years), ≥1 severe hypo event in previous 12 months (5 vs. 8%), education < bachelor's degree (52 vs. 57%), and race (non-Hispanic whites, 73 vs. 76%). Despite only 1 study related contact after wk 4 and none after wk 12, the trial was completed by 97% of participants and CGM use was high, with 93% using CGM ≥6 days/wk at wk 24. A1c change from baseline to 24 wks was greater in the CGM than the SMBG group (−0.9±0.7 vs. −0.5±0.8, mean adjusted difference −0.5%, P<0.001). Secondary A1c analyses were confirmatory and treatment effect appeared largest at higher baseline A1c (Table 1). A1c reductions were similar across ages, baseline SMBG frequencies, education, and diabetes type. CGM users increased time in range, decreased time <70 and 60 mg/dL, and decreased time >180 and 300 mg/dL more than SMBG users. CGM benefits a wide range of adults with T1D and T2D using MDI in suboptimal control. Table 1A1C outcomes at 24 weeks CGM Group (N=179) SMBG Group (N=128) Between-Groups Difference 95% CI P ΔA1C from Baseline (BL) All Subjects (Primary Outcome) −0.9±0.7 −0.5±0.8 −0.5 −0.6 to −0.3 <0.001 BL A1C ≥8.0% −1.0±0.7 −0.6±0.8 <0.001 BL A1C ≥8.5% −1.2±0.7 −0.6±0.8 <0.001 BL A1C ≥9.0% −1.4±0.8 −0.7±0.8 <0.001 Odds Ratio 95% CI P Secondary A1C Outcomes at 24 Weeks A1C <7.5% 66 (37%) 27 (21%) 2.6 1.5 to 4.7 0.001 A1C Reduction ≥1% or A1C <7.0% 86 (48%) 33 (26%) 2.7 1.6 to 4.6 <0.001 Open table in a new tab