Carbohydrate metabolism and transformation of pre-diabetes into type 2 diabetes mellitus depending on diagnostic methods in nondiabetic patients with hypertension and high cardiovascular risk

Abstract

Objective. To assess the glycemia status and risk of progression to diabetes mellitus (DM) depending on diagnostic criteria (fasting glucose, 2-h glucose, glycated hemoglobin HbA1c and their combination) in hypertensive patients with high cardiovascular (CV) risk without known DM. Methods. 433 hypertensive patients with high CV risk were included in the study. Stratification of CV risk was done in accordance with national guidelines for the management of arterial hypertension (2010). Patients were divided into groups with noncomplicated (n = 201) and complicated (n = 232) arterial hypertension. Follow-up was 6 years. Fasting glucose, 2-h glucose during oral glucose tolerance test (OGTT) and HbA1c were assessed in all patients each 6 months. The patients were divided into groups with normoglycemia, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), its combination (IFG/IGT), isolated HbA1c 5,7-6,4 % and newly diagnosed DM (ADA2011). Results. Impaired glucose status was diagnosed in 82 % of patients with arterial hypertension and high CV risk according to fasting glucose, 2-h glucose, HbA1c diagnostic criteria. IFG was the most prevalent in patients with non-complicated arterial hypertension, and newly diagnosed DM — in complicated arterial hypertension. HbA1c used as an additional criterion of impaired glucose metabolism in addition to OGTT contributes to the better identification of newly diagnosed DM in high risk hypertensive patients for 10 %. Two-hour hyperglycemia has higher predictive value for diagnosing DM in patients with complicated arterial hypertension, thus imposing the obligatory OGTT assessment in this group of patients. OGTT is desirable, but non-obligatory in patients with non-complicated arterial hypertension. Conclusion. The assessment of HbA1c and fasting glucose/2-h postload glucose has independent and complementary importance and helps to identify patients with different pathogenetic mechanisms of glucose metabolism impairment. Prognostic value of HbA1c as a diagnostic criterion of risk progression to DM is comparable with fasting glucose/ 2-h postload glucose assessment.