Type 2 diabetes: principles of treatment (part 1)

This article series is based on the Stewart Tomlinson BMJ Learning training course – just-in-time training. Therefore, the information presented is a reflection of the British recommendations for the diagnosis and treatment of diabetes. A key feature of these recommendations is their validity in terms of evidence-based medicine. This should be taken into account when prescribing treatment to patients and correlated with the National Clinical Recommendations for the treatment of diabetes.  

Treatment principles

• Patients with type 2 diabetes mellitus (type 2 diabetes) should receive ongoing medical care with an assessment of the risk of microvascular and cardiovascular complications.  
• The data of all patients with type 2 diabetes should be entered in a special register of the medical institution. This makes it possible to ensure their accounting, set the time for consultations, as well as conduct timely necessary information.
• During treatment, targets should be selected individually for each patient, taking into account the real possibility of their achievement. Their overstatement may reduce the effectiveness of treatment and lead to the development of severe hypoglycemia (a decrease in blood glucose).
• When coordinating target indicators with the patient, all risk factors for the development of cardiovascular diseases (CVD) must be taken into account .  

Targets for Type 2 Diabetes

The table shows the recommended targets for glucose, blood pressure and blood lipids. ^2,3  

Justification of targets in the treatment of type 2 diabetes

Blood glucose

The ADVANCE study in 2008 evaluated the positive impact of improved glycemic control on reducing the risk of micro- and macrovascular complications in patients with type 2 diabetes. Intensive glycemic control (maintaining HbA _1c hemoglobin at 6.5% instead of 7.3%) over 5.5 years led to the following results:  

• a decrease in the number of microvascular complications by 14%;
• a slight decrease in the incidence of cardiovascular diseases and mortality from them ⁴ .

By way of comparison: during the ACCORD study in a group of patients with type 2 diabetes who are at high risk of developing CVD in whom the HbA _1C hemoglobin level was ≥7.5%, treatment aimed at achieving an HbA _1C level of 7.0-7, 9%, led to an increase in mortality over 3.5 years ⁵ . This is probably a consequence of the development of cardiovascular complications in the presence of severe hypoglycemia. This result underlines the importance of identifying individual treatment goals for patients with type 2 diabetes.   

In 2011, in Cochrane review ⁶ 20 clinical studies have evaluated the positive effect of intensive treatment aimed at lowering blood glucose, total mortality, mortality from cardiovascular disease and frequency of microvascular complications in patients with type 2 diabetes. The following results were obtained: 

• No significant differences were found between the effect of intensive and standard glycemic control on overall mortality or mortality from CVD. 
• Intensive glycemic control reduced the risk of amputations, retinopathy (pathology of the retina) and nephropathy (pathology of the kidneys).

According to the results of three other studies, during which a comprehensive meta-analysis of an intensive decrease in blood glucose was carried out, the following results ^7–9 were also obtained :

• Treatment aimed at intensively lowering blood glucose levels does not have a positive effect on reducing overall mortality or CVD mortality in adult patients with type 2 diabetes, ^7–9 .
• Compared with patients receiving conventional treatment, the risk of developing severe hypoglycemia in patients from the intensive care group increases by more than 2 times ⁷ .

Arterial hypertension

Arterial hypertension is defined by the British Hypertension Society as a disease characterized by a blood pressure level of ≥140 / 90 mmHg. t. It is 1.5-3.0 times more likely to occur in patients with type 2 diabetes than in people without this disease. 

When studying arterial hypertension in diabetes mellitus as part of a prospective study of this disease in the UK (UK Prospective Diabetes Study, UKPDS), “strict” control of blood pressure (144/82 mm Hg) was compared with “less strict” (154/87 mm mercury) ¹⁰ . In the first case, there were lower incidence rates of myocardial infarction (14% in the strict control group compared with 21% in the less strict control group) and stroke (5% in the strict control group compared to 8.7% in the less strict control group).        

It has been established that strict control of blood pressure in patients with arterial hypertension and type 2 diabetes allows us to achieve a clinically significant reduction in the risk of diabetes-related death, complications of this disease, the progression of diabetic retinopathy and visual impairment. 

In a study aimed at finding the optimal methods for treating hypertension (Hypertension Optimal Treatment, HOT), we compared patients who received intensive treatment for whom the target level of diastolic blood pressure was 80 mm Hg. Art., with patients receiving standard treatment, for whom this target was 90 mm RT. Art. ¹¹ It was found that intensive treatment reduced the incidence of any cardiovascular disorders (4.4% in the intensive treatment group compared to 9% in the standard treatment group). 

Lipids

A Heart Protection Study studied the role of a 40 mg dose of simvastatin in primary prevention of CVD. ¹² It included 3,985 patients aged 40 to 80 years old with type 1 or type 2 diabetes without CVD and a history of total cholesterol> 3.5 mmol / L. Overall, 9.1% of patients taking a drug containing simvastatin developed a coronary attack, had a stroke, or had a need for revascularization compared with 13.5% of patients taking a placebo.    

In June 2004, the results of a study of the efficacy of a drug containing atorvastatin (Collaborative Atorvastatin Diabetes Study, CARDS) were presented at the annual conference of the American Diabetes Association. The aim of the study was to study the benefits of a drug containing atorvastatin in a dose of 10 mg for primary prevention under the following conditions:

• the patient has type 2 diabetes; 
• low density lipoprotein cholesterol (LDL) ≤4.14 mmol / L;
• the presence of one of the other risk factors for CVD (arterial hypertension, smoking, retinopathy, microalbuminuria – the release of albumin protein in the urine). 

Taking a drug containing atrovastatin reduced the incidence of serious cardiovascular disease by 37% compared with placebo. 

The British Recommendations note that all patients suffering from type 2 diabetes for more than 10 years, and all patients with this pathology are older than 40, are at a fairly high risk of developing CVD, and therefore they will benefit from statin therapy , with the exception of patients with clear contraindications for this treatment. 

Prescribing Aspirin

The latest version of the British recommendations contains information on the need to prescribe aspirin in small doses (75 mg) to patients suffering from type 2 diabetes for more than 10 years, and patients with this ailment older than 50 years. However, a 2009 meta-analysis of primary prevention of CVD in patients with diabetes ¹³ showed that the increased risk of developing intracranial hemorrhage and gastrointestinal bleeding exceeds all the benefits of aspirin. One 2009 Medicines and Healthcare Products Regulatory Authority (MHRA) drug safety report (2009) recommends a case-by-case analysis of the benefit / risk ratio for aspirin for primary prevention. therapy, in particular, to assess the presence of risk factors for vascular diseases and gastrointestinal bleeding.