Acta Diabetologica

, Volume 49, Supplement 1, pp 153–160 | Cite as

The importance of HbA1c and glucose variability in patients with type 1 and type 2 diabetes: outcome of continuous glucose monitoring (CGM)

  • Giovanni Sartore
  • Nino Cristiano ChilelliEmail author
  • Silvia Burlina
  • Paola Di Stefano
  • Francesco Piarulli
  • Domenico Fedele
  • Andrea Mosca
  • Annunziata Lapolla
Original Article


Glucose variability has recently been investigated in diabetic patients in several studies, but most of them considered only a few variability indicators and did not systematically correlate them with patients’ HbA1c levels and other important characteristics. In thus study, the correlations between HbA1c levels and metabolic control (average glucose, AG), glucose variability (SD, CONGA, MAGE, MODD, BG ROC), hyperglycemia (HBGI), hypoglycemia (LBGI) and postprandial (AUC PP) indices were investigated in patients with type 1 and type 2 diabetes. The study involved 68 patients divided into 3 groups as follows: 35 patients had type 1 diabetes (group 1); 17 had type 2 diabetes and were taking multiple daily injections (MDI) of insulin (group 2); and 16 patients had type 2 diabetes treated with OHA and/or basal insulin (group 3). The indicators were obtained over at least 48 h using a continuous glucose monitoring (CGM) system. HbA1c levels were measured at the baseline and after CGM. HbA1c correlated significantly with AG (r = 0.74), AUC PP (r = 0.69) and HBGI (r = 0.74), but only in type 1 diabetic patients. Patients with longstanding disease and type 1 diabetes had a greater glucose variability, irrespective of their HbA1c levels. Insulin therapy with MDI correlated strongly with HbA1c, but not with glucose variability. HbA1c levels identify states of sustained hyperglycemia and seem to be unaffected by hypoglycemic episodes or short-lived glucose spikes, consequently revealing shortcomings as a “gold standard” indicator of metabolic control. Glucose variability indicators describe the glucose profile of type 1 diabetic patients and identify any worsening glycemic control (typical of longstanding diabetes) more accurately than HbA1c tests.


Glucose variability Continuous glucose monitoring HbA1c Standard deviation Hyperglycemia 


Conflict of interest

The authors have no competing financial interests to disclose.


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Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Giovanni Sartore
    • 1
  • Nino Cristiano Chilelli
    • 1
    Email author
  • Silvia Burlina
    • 1
  • Paola Di Stefano
    • 2
  • Francesco Piarulli
    • 1
  • Domenico Fedele
    • 1
  • Andrea Mosca
    • 3
  • Annunziata Lapolla
    • 1
  1. 1.Department of Medical and Surgical SciencesUniversity of PadovaPaduaItaly
  2. 2.Medtronic Italia S.p.A.RomeItaly
  3. 3.Department of Biomedical Sciences and TechnologiesUniversity of MilanoMilanItaly

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