Bolus Insulin Dose Error Distributions Based on Results From Two Clinical Trials Comparing Blood Glucose Monitoring Systems

Abstract

Background: In 2 previous clinical trials, fingertip capillary blood samples were evaluated using prespecified blood glucose monitoring systems (BGMSs) and a reference YSI glucose analyzer. In post hoc analyses, hypothetical insulin doses were calculated using these blood glucose measurements; dosing errors were compared for each trial.

Method: For each blood glucose measurement, premeal bolus insulin dosing was determined for a hypothetical person, assuming a 60-g carbohydrate meal and 100-mg/dL target blood glucose level (adjusting 1/25 insulin sensitivity and 1/15 insulin:carbohydrate ratio inputs to account for BGMS measurement error). Dosing error was the difference between doses calculated using the BGMS and YSI results.

Results: In Clinical Trial 1, 95% dose error ranges (in units of insulin) were: CONTOUR^®NEXT EZ BGMS (EZ), -0.9 to 0.5; Accu-Chek^® Aviva BGMS (ACA), -0.5 to 1.8; FreeStyle Freedom Lite^® BGMS (FFL), -3.2 to -0.3; OneTouch^® Ultra^®2 BGMS (OTU2), -4.1 to 0.3; and Truetrack^® BGMS (TT), -3.9 to 2.2. In Clinical Trial 2, these ranges were: CONTOUR^®NEXT BGMS (CN), -0.7 to 1.7; Accu-Chek^® Aviva Nano BGMS (ACAN), -1.3 to 1.8; FreeStyle Lite^® BGMS (FSL), -5.1 to 0.2; OTU2, -1.9 to 1.2; OneTouch^® Verio^® Pro BGMS (OTVP), -1.0 to 1.9; and TT, -5.1 to 1.7. Within each trial, EZ and CN had statistically significantly smaller insulin dose error ranges than other BGMSs ( P <0.0001).

Conclusions: The ranges of insulin dose errors were statistically significantly smaller with EZ and CN than with all other BGMSs in this post hoc analysis. Differences in BGMS accuracy could result in clinically important differences in insulin dosing.

Keywords: blood glucose monitoring; diabetes management; dosing errors; insulin; self-monitoring of blood glucose.

Figure 1.

Middle (median) 95% distribution of bolus insulin dose errors (Clinical Trial 1).^a,b BGMS, blood glucose monitoring system; YSI, YSI glucose analyzer. ^aThe insulin sensitivity input (1/25) and the insulin:carbohydrate ratio (1/15) were adjusted based on the observed error of the BGMS result versus the YSI measurement. ^bSolid white circles represent the median dose error; horizontal bars represent the 95% dose error range. ^cP <0.0001 versus EZ (Kolmogorov-Smirnov test).

Figure 2.

Middle (median) 95% distribution of bolus insulin dose errors (Clinical Trial 2).^a,b BGMS, blood glucose monitoring system; YSI, YSI glucose analyzer. ^aThe insulin sensitivity input (1/25) and the insulin:carbohydrate ratio (1/15) were adjusted based on the observed error of the BGMS result versus the YSI measurement. ^bSolid white circles represent the median dose error; horizontal bars represent the 95% dose error range. ^cP <0.0001 versus CN (Kolmogorov-Smirnov test).