Relationship between HbA1c on target, risk of silent hypoglycemia and glycemic variability in patients with type 2 diabetes mellitus.

OBJECTIVE

We aimed to compare time spent at low glucose level (silent hypoglycemia, glucose <3.0 mmol/l) and glycemic variability in patients who reached HbA1c <7.0% with those who did not.

RESEARCH DESIGN AND METHODS

In 108 type 2 diabetic patients the interstitial glucose concentration was measured with CGMS (Continuous Glucose Monitoring System) over 72 h. Patients were divided in group 1 with an HbA1c <7.0% (n=63) and group 2 with an HbA1c≥7.0% (n=45).

RESULTS

24% in group 1 experienced silent hypoglycemia vs. 11% in group 2 (n. s.), duration of silent hypoglycemia over 48 h was 27±71 min vs. 7±36 min (n. s.). This was also valid for the subgroups treated with insulin. Patients in group 2 had a significantly higher standard deviation of average glucose (2.3±0.8 vs. 1.3±0.6; p<0.001) and MAGE (mean amplitude of glycemic excursions) (4.8±2.1 vs. 2.6±1.1; p<0.001).

CONCLUSION

Silent hypoglycemia tended to occur more often and to last longer in patients with HbA1c <7%. However, patients with HbA1c >7% had a higher glycemic variability. HbA1c >7% wasn't a reliable indicator of lower risk of hypoglycemia.