The impact of structured self-monitoring of blood glucose on glycaemic variability in non-insulin treated type 2 diabetes: The SMBG study, a 12-month randomised controlled trial.

Background And Aims: There is inconsistent evidence supporting the self-monitoring of blood glucose (SMBG) in people with non-insulin treated type 2 diabetes (T2D). Structured SMBG protocols have a greater impact on glycaemic control than unstructured SMBG and may improve measures of glycaemic variability (GV), though few previous studies have reported on specific GV outcomes. Our aim was to determine the impact of structured SMBG on simple measures of GV in people with T2D.

Methods: Participants undertook structured SMBG over 12 months, with HbA recorded at baseline and at 3-monthly follow-up. For each participant, the mean blood glucose (MBG), fasting blood glucose (FBG), standard deviation BG (SD-BG), coefficient of variation of BG (CV-BG), mean absolute glucose change (MAG) and HbA were determined for each 3-month period. Responders were participants with an improvement in HbA of ≥5 mmol/mol (0.5%) over 12 months.

Results: Data from two hundred and thirty-one participants were included for analysis. Participants had a baseline median [interquartile range] HbA 68.0 [61.5-75.5] mmol/mol (8.4%). Participants demonstrated significant improvements in the MBG (-1.25 mmol/L), FBG (-0.97 mmol/L), SD-BG (-0.44 mmol/L), CV-BG (-1.43%), MAG (-0.97 mmol/L), and HbA (-7.0 mmol/mol) (all p < 0.001) at 12 months compared to these measures collected within the first 3 months of SMBG. Responders had a significantly higher baseline median [interquartile range] HbA of 70.0 [63.0-78.0] mmol/mol compared to 61.0 [56.5-66.0] mmol/mol in non-responders (P < 0.001).

Conclusions: Structured SMBG improved all the observed measures of GV. These results support the use of structured SMBG in people with non-insulin treated T2D.