Endocrine Abstracts

Introduction: Severe hypoglycemia and retinopathy are two of the main complications of diabetes mellitus (DM). Traditionally, glycosylated hemoglobin (or A1C) has been used as the gold standard measurement of glycemic control; however, there is a significant percentage of complications riskassociated with the evolution of diabetes that is not fully explained by this single marker. Short and long-term glycemic variability has been postulated as one of the main variables that contribute to increase that risk.

Objectives: To determine if there is an association between any parameter of measurement of short and/or long-term glycemic variability with the risk of developing severe hypoglycemia and retinopathy.

Material and Methods: A case-control study was performed, with descriptive and analytical aspects on 103 type 1 DM patients controlled by self-monitoring of capillary blood glucoseusing glucometers with bolus calculator. Patients are being treated in the Hospital Clínico Lozano Blesa’s Endocrinology and Nutrition Department. Glycemic variability data has been collected from the download of glucometers and from the A1C values ​​obtained in successive blood tests. Statistical analysis was performed with Mann-Whitney U test, χ² test and Fisher’s exact test. The statistical significance has been accepted for values of P < 0.05.

Results: A lower mean BMI (22.25 vs 25.90 kg/m², P 0.016) and a higher standard deviation of blood glucose mean (81.3 vs 68.6 mg/dl; P 0.003) were observed among patients with severe hypoglycemia, and there were more episodes of severe hypoglycemia in those patients with an unfavorable Clarke test (4 vs 0; P 0.035). On the other hand, the average patients’ age (47.89 vs 37.43 years; P 0.001) and the time of evolution of diabetes (36.64 vs 15.42 years; P < 0.001) were higher among those patients with retinopathy, but not the age of onset of DM (11.26 vs 22.19; P 0.001) nor the C-peptide value (0.052 vs 0.251 ng/ml; P < 0.001).

Conclusions: Severe hypoglycemia is more frequent among patients with greater short-term glycemic variability (defined as the standard deviation of mean glycemia) while no association has been observed with any measure of long-term variability. In opposition, retinopathy has not shown an association with any parameter of glycemic variability.