Continuous glucose monitoring (CGM) helps delineate dysglycemic patterns including glycemic variability (GV). We aimed to identify CGM-metric related factors affecting optimal glycemic control in Type 2 diabetic (T2DM) patients.
We enrolled 52 T2DM patients on stable lifestyle and oral anti-diabetic drugs (OADs) for atleast 3 months. Clinical and laboratory evaluation was followed by CGM (Medtronic IPRO®2, Enlite sensor) for a minimum of 48 hours.
Mean age of study participants was 52.6 ± 7.5 years. Median diabetes duration and HbA1c were 6.5 years (2-11) and 8.8% (7.7- 11) respectively. All patients were on OADs, with additional 13.5% on insulin. Median CGM readings were 831 (802-1069.5), with satisfactory glucometer cross-calibration. HbA1c had a positive correlation with average glucose (ρ=0.764, p<0.001), and negative correlation with time-in-range (ρ=-0.722, p<0.001) by Spearman’s rho (ρ) analysis. Area-under-curve (AUC) analysis revealed fasting hyperglycemia as the major contributor to HbA1c overall, but the contribution of postprandial hyperglycemia increased with improving glycemic status, increasing from 16.1% (10.2- 21.1) to 33.4% (17.6- 40.1) in subgroups with HbA1c>10% and <8% respectively. Time-below-range, TBR ≥4% was observed in 8 (15.4%) patients; 75% of these hypoglycemic episodes were asymptomatic. Coefficient-of-variation (CV%) had an AUC of 0.793 (95% CI:0.654-0.931, p=0.009) for predicting a TBR ≥4%, with cut-off of 26.4% having 100% sensitivity and 63.6% specificity. Higher TBR and CV% were noted in the lower HbA1c tertiles, with consistent negative correlation with HbA1c (ρ=-0.396, p=0.004 and ρ= -0.312, p= 0.024 respectively), implying higher GV with nearing HbA1c targets.
Postprandial hyperglycemia, asymptomatic hypoglycemia, higher CV% are the key areas requiring focus in T2DM patients with HbA1c nearer to “target” values. CGM can help to identify these barriers and therapy tailored accordingly to achieve optimal glycemic control. Accurately quantifying GV using CGM could well be the “third pillar” on which the future of glycemic management rests.