• diabetes is a syndrome characterized by the inability of the body to process glucose and maintain its levels within physiological limits due to absolute (↓ secretion) or relative insulin deficiency (↑ resistance), resulting in altered glycide, lipid, and protein metabolism
  • it is a heterogeneous group of diseases that accelerate the development of atherosclerosis and potentiates the development of microangiopathy; the increased risk of thrombotic events is also related to concomitant dyslipidemia, endothelial dysfunction, platelet hyperreactivity, and impaired fibrinolytic balance
  • diabetes increases cardiovascular morbidity and mortality and is an independent risk factor for stroke
    • the risk of stroke is 1.8 to 6 times higher compared to the non-diabetic population, and the risk increases with poor compensation
    • the risk is higher in the 20-65 year old population (5-14 times higher) [Khoury, 2013]
    • patients with DM have a worse prognosis for stroke (3 times higher mortality) and a 2 times higher risk of stroke recurrence
  • diabetes is often associated with metabolic syndrome X
    • hyperglycemia (DM or impaired GTT), insulin resistance
    • dyslipidemia (in DM, typically ↑ TG and LDL occur)
    • arterial hypertension
    • abdominal obesity (waist circumference  ≥ 102cm in men,  ≥ 88cm in women)
  • the risk of cardiovascular disease (CVD) is increased in the presence of other vascular risk factors
    • management of risk factors associated with metabolic syndrome in type 2 DM (T2DM) is essential for stroke prevention
  • absolute – destruction of β-cells of the islets of Langerhans
  • relative
    • abnormal insulin
      • abnormal insulin molecule (mutation)
      • defective conversion of preproinsulin to insulin
      • circulating antibodies against insulin or the receptor
    • insulin resistance of the target tissue
      • receptor defect
      • post-receptor disorder


Type 1 diabetes mellitus (T1DM)

  • autoimmune (5-10%) x idiopathic (no autoantibodies present)
  • defect in insulin secretion; if untreated, associated with ketoacidosis
  • most common in adolescents, but also in adults (LADA – Latent Autoimmune Diabetes in Adults), often in non-obese individuals
  • exogenous insulin must be administered
  • slow-onset T1DM
  • typically in individuals > 30 years of age, usually mistaken for T2DM
  • positive antibodies (autoimmunity), slower progression, and diabetes manifestations are milder
  • initially well controlled by diet and PAD, does not lead to diabetic ketoacidosis, but gradually insulin dependence develops (months – years)

Type 2 diabetes mellitus (T2DM)

  • mostly in adults
  • there is enough endogenous insulin to prevent ketoacidosis, but levels are often either subnormal or relatively inadequate due to low tissue sensitivity (tissue insulin resistance)
  • obesity can contribute to resistance
  • approx. 5% of T2DM cases
    • a group of monogenic diabetic disorders with familial occurrence and a well-defined mode of inheritance (usually AD)
    • approx. 6 types (MODY1-6)
  • early manifestation (childhood, adolescence, or early adulthood)
  • independent of obesity, individuals do not have metabolic syndrome
  • pathophysiology: genetically determined β-cell dysfunction without evidence of autoimmunity
    • MODY due to mutations in glucokinase (MODY2) (responsible for the sensitivity of the β-cell to glycemia)
    • MODY due to mutations in the transcription of factors responsible for regulating insulin production in the β-cells)

Gestational diabetes mellitus

  • a disorder of glucose metabolism that occurs during pregnancy
    • it is caused by a transient increase in insulin resistance and usually resolves after delivery
    • blood sugar levels are only slightly elevated due to gestational diabetes, so women have no obvious difficulties
    • the increased amount of glucose reaches the baby via the placenta, leading to excessive growth and an increased risk of diabetes in adulthood. Mothers are also at increased risk of developing T2DM in later decades
  • risk factor:
    • age > 30 years
    • overweight
    • smoking
    • family history of DM
  • diagnosis is made with an oral glucose tolerance test (oGTT)

    • between 24-28 weeks of pregnancy
    • in women at risk between 16-18 weeks of pregnancy

Other specific types

  • genetic defects of pancreatic β-cells
    • monogenic DM type MODY 1-6 (Maturity-onset diabetes of the young) – about 5% of T2DM
    • mitochondrial DNA mutations
  • genetic defects causing insulin resistance (lipoatrophic DM)
  • diseases of the exocrine pancreas (pancreatitis, pancreatic tumor, cystic fibrosis, hemochromatosis)
  • endocrinopathies (Cushing’s syndrome, acromegaly, pheochromocytoma, hyperthyroidism, etc.)
    iatrogenic DM
  • other genetic syndromes associated with DM (Down syndrome, Klinefelter syndrome, Turner syndrome)

Diagnostic evaluation

Dg. criteria for diabetes mellitus
  • Fasting Plasma Glucose (FPG) ≥ 6.7 mmol/L  (≥ 120 mg/dL)   (fasting > 8 hours) – repeat testing required
  • glycemia at any time during the day ≥ 11.1 mmol/l (≥ 200 mg/dL) regardless of the last meal
  • GTT  (75g glucose in water) : ≥ 11.1 mmol/L (≥ 200 mg/dL)
    • glucose tolerance test for the detection of gestational diabetes is slightly different (see here)
  • glycated hemoglobin (HbA1c) ≥ 48 mmol/mol
    • normal value< 38
    • borderline value 38-48
  • clinical symptoms (polyuria, polydipsia)
Impaired Fasting Glucose (IFG)
  • fasting glycemia  5.6 – 6.7 mmol/L  (100.5-120 mg/dL)
Impaired glucose tolerance (IGT)

Must be confirmed by repeated measurements


→ management of acute hyperglycemia
→ management of acute hypoglycemia
→ continuous insulin therapy protocol

The main goals of long-term diabetes management
I. Achieving or approaching normoglycemia in the long term

  • intensive treatment of chronic hyperglycemia in diabetic patients reduces the risk of developing microvascular complications (a positive effect on the development of macroangiopathy has not been proven)

II. Careful compensation of associated risk factors and comorbidities (especially in T2DM)

  • target BP < 130/80 mmHg
    • monotherapy or combination; always use ACEI or sartan to prevent and treat DM nephropathy; in non-diabetics, it reduces the risk of developing diabetes
  • correction of dyslipidemia
  • treatment of obesity
    • in diabetic patients with BMI > 30.0 kg/m2, sibutramine or lipase inhibitors (orlistat) may be indicated in combination with diet and exercise or other pharmacotherapy
  • treatment and prevention of diabetic nephropathy (ACEIs, sartans)
  • pharmacological treatment differs between type 1 and type 2 diabetes
    • T1DM requires insulin treatment
    • T2DM treatment starts with lifestyle modification measures and metformin; if the combination of oral antidiabetic drugs and all measures fail to achieve the desired glycemic control, a decision must be made whether to add insulin
Target values for metabolic syndrome therapy
Fasting glycemia (8 h after last meal)
  • an indicator of overnight and morning glycemic events
  • predictor of cardiovascular complications

6 mmol/L

Glycemia 1-2 hod. after meal
  • independent risk factor for heart and large vessel disease
  7,5 mmol/L
HbA1c (glycated hemoglobin)

  • an indicator of long-term DM compensation – the so-called “long sugar”
  • the more sugar in the blood, the more it binds to hemoglobin, the higher the risk of late complications (vascular, nervous)
  • reflects the average glycemia in the last 3 months (lifetime of the erythrocyte)
  • previously HbA1c expressed in %, now in mmol HbA1c/mol Hb
    • HbA1c value in mmol/mol corresponds to 10 times the original value in % – e.g., originally HbA1c 5.5% – now 55 mmol/mol
< 38 mmol/mol
diabetics (well-controlled)
43-53  mmol/mol
Blood pressure  → arterial hypertension
 < 130/80 mmHg
Lipids  → dyslipidemia
Body mass index (BMI)
Waist circumference (men/women)   < 94 cm / < 80 cm
The finding of borderline or mildly abnormal renal function (see below) should lead to more intensive treatment of diabetes and arterial hypertension to achieve the best possible compensation

  • slightly elevated serum creatinine concentration (men 115-133 and women 107-124 µmol/L)
  • decreased glomerular filtration rate (< 60 ml/min/1.73 m2, ≤ 1.0 ml/s/1.73 m2)
  • microalbuminuria (30-300 mg/24 h) or albumin/creatinine ratio men 2.5-30, females 3.0-30 g/mol creatinine)
  • proteinuria > 300mg/24h

Non-pharmacological measures

  • healthy diet
    • diabetic diets with 175 g, 200 g, or 225 g of carbohydrates or reduction diets
    • limit the intake of animal fats, processed meats, and juices
    • increase intake of vegetable fats, nuts, fiber, coffee, and fish
  • physical activity
    • take into account age, type of diabetes, weight, and presence of associated complications
    • in addition to a structured exercise program, a general increase in physical activity throughout the day (e.g., taking the stairs, walking or biking to work, avoiding prolonged periods of sitting) should be encouraged
  • weight loss of at least 5-10%

Peroral antidiabetics (PADs)

  • first-line therapy is metformin
    • it decreases hepatic glucose production and increases peripheral insulin sensitivity, leading to a reduction in hyperglycemia in adults with T2DM 
    • a systematic review found no evidence of reduced CVD events or CVD deaths with metformin
    • must be used with caution in patients with CKD
  • start therapy with the lowest possible dose
  • if there is an inadequate response, increase the dose, but do not use the maximum dose; instead, switch to a combination of antidiabetic drugs

Newer peroral antidiabetics

  • newer glucose-lowering drugs have been demonstrated to reduce CVD events in adults with T2DM and high cardiovascular risk
    • sodium-glucose co-transporter-2 inhibitors (SGLT2i)
      • act in the proximal tubule to increase urinary excretion of glucose and sodium, leading to a reduction in HbA1c, body weight, and BP
    • glucagon-like peptide-1 receptor agonists (GLP-1RA) (semaglutide, liraglutide, dulaglutide, etc. ) – its stroke risk reduction is most strongly supported by the evidence
      • GLP-1 agonists increase insulin and glucagon production in the liver, increase glucose uptake in muscle and adipose tissue, and decrease hepatic glucose production
      • meta-analysis of eight randomized studies that calculated a risk reduction of about 15% whether calculated for fatal or nonfatal strokes (Goldenberg, 2022)
  • weight loss has been suggested as one potential mechanism for CV risk reduction (that goes beyond glycemic control); however, weight loss with SGLT2 inhibitors appears to be more effective than with GLP-1 receptor inhibitors
  • according to ACC/AHA guidelines 2019, it may be reasonable to initiate these 2 classes of medications for the primary prevention of CVD in T2DM patients with additional CV risk factors


Management of other vascular risk factors

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Diabetes mellitus