Type 2 Diabetes

What is diabetes?

Diabetes is a chronic (long-lasting) health condition that affects the body's ability to use the sugar in the food we eat after we've absorbed it. Most people's bodies naturally produce the hormone insulin, which helps convert sugar into energy. When you have diabetes, either your body doesn't produce insulin (type 1 diabetes) or doesn't use insulin well (type 2 diabetes), causing your blood sugar to rise. Elevated blood sugar levels cause serious health problems over time.

Who should be screened?

Every adult 40 years of age and older should receive regular screening for type 2 diabetes. Some individuals should begin screening at a younger age based on the presence of risk factors.

Risk factors for developing type 2 diabetes:

• Family history (first-degree relative with type 2 diabetes)
• High risk populations (e.g. African, Arab, Asian, Hispanic, Indigenous, or South Asian descent; and low socioeconomic status)
• History of gestational diabetes mellitus, prediabetes, impaired fasting glucose, or impaired glucose tolerance
• History of delivery of a macrosomal infant
• Cardiovascular risk factors (e.g. low HDL, high triglycerides, hypertension, overweight, abdominal obesity, and smoking)
• Presence of end organ damage associated with diabetes (e.g. retinopathy, neuropathy, nephropathy)
• Presence of vascular disease associated with diabetes (e.g. coronary artery disease, cerebrovascular disease, or peripheral vascular disease)

Frequency of screening:

• Every 6 months to 3 years depending on risk factors.

How is type 2 diabetes diagnosed?

In contrast to other diseases, there is no distinction between screening and diagnostic testing for diabetes. Diabetes is diagnosed with two abnormal results of either:

• HbA1c ≥6.5%
• Fasting plasma glucose ≥7.0 mmol/L (126 mg/dL)

If symptoms of hyperglycemia are present, a diagnosis of diabetes can be made with only one abnormal result.

Targets for glycemic control

Blood glucose lowering therapies

Treatment of type 2 diabetes involves a stepwise approach to interventions. Lifestyle interventions are strongly encouraged as the primary means of treating patients newly diagnosed with type 2 diabetes who are asymptomatic and not severely above their HbA1c target.

1. Healthy behaviour interventions are the most important initial steps for patients newly diagnosed with type 2 diabetes. These include nutritional therapy, exercise, and weight management.

2. The second step for essentially all patients with type 2 diabetes is to start taking metformin.

3. Patients with type 2 diabetes who are also diagnosed with cardiovascular disease benefit from the addition of a medication shown to reduce cardiovascular risk, such as:

• Empagliflozin (Jardiance), an SGLT2 inhibitor
• Liraglutide (Victoza, Saxenda), a GLP-1 receptor agonist
• Semaglutide (Ozempic, Rybelsus, Wegovy), a GLP-1 receptor agonist
• Canagliflozin (Invokana), an SGLT2 inhibitor

4. Some patients require additional glucose-lowering medications to achieve adequate glycemic control. Examples of such medications include:

• Gliclazide (Diamicron) or glimepiride (Amaryl), both sulfonylureas
• Repaglinide (GlucoNorm), a meglitinide analog
• Acarbose (Precose, Glucobay), an alpha-glucosidase inhibitor
• Pioglitazone (Actos) or Rosiglitazone (Avandia), both thiazolidinediones
• Sitagliptin (Januvia), a DPP-4 inhibitor
• An SGLT-2 inhibitor or GLP-1 receptor agonist (see step #3 above)
• Insulin

Medications for cardiovascular protection

Many patients with type 2 diabetes have improved outcomes if they take additional medications for cardiovascular protection. These medications are indicated for specific patient populations:

Patients with established cardiovascular disease—this includes cardiac ischemia (silent or overt), peripheral arterial disease, and cerebrovascular/carotid disease. Patients with these conditions benefit from taking:

• Statin therapy to a target LDL of <2.0 mmol/L (77 mg/dL)
• ACE-inhibitor or ARB at a dose demonstrated to provide vascular protection e.g. perindopril 8 mg once daily (EUROPA trial), ramipril 10 mg once daily (HOPE trial), or telmisartan 80 mg once daily (ONTARGET trial)
• Aspirin, for secondary prevention of cardiovascular disease

Patients >55 with cardiovascular risk factors or patients with microvascular disease—including retinopathy, kidney disease (ACR >2.0), and neuropathy. Patients with these conditions benefit from taking:

• Statin therapy to a target LDL of <2.0 mmol/L (77 mg/dL)
• ACE-inhibitor or ARB at a dose demonstrated to provide vascular protection e.g. perindopril 8 mg once daily (EUROPA trial), ramipril 10 mg once daily (HOPE trial), or telmisartan 80 mg once daily (ONTARGET trial)

Patients >40 or patients >30 with diabetes for over 15 years benefit from taking:

• Statin therapy to a target LDL of <2.0 mmol/L (77 mg/dL)

Can diabetes be cured?

Some cases of type 2 diabetes are caused by being overweight or obese. The insulin-resistance activity of adipose tissue (fat) is responsible for these patients' hyperglycemia. Some other cases involve patients who consume carbohydrates excessively, exceeding their body's ability to utilize the glucose they absorb, resulting in hyperglycemia. In some cases, resolving the underlying problem (excessive adipose tissue or dietary carbohydrates) can reverse diabetes, which effectively results in a "cure" of the condition.

Glycemic control assessments

A family physician helps their diabetic patients ensure adequate control of their blood glucose levels. Initially, after diagnosis this will involve checking HbA1c levels every 90 days. If target levels are achieved then periodic HbA1c assessments will be adequate to ensure ongoing glycemic control.

Some patients may have difficulty achieving adequate glycemic control and may benefit from more intensive monitoring. This can be achieved with finger-prick testing using a glucometer. A common approach to assess whether diet, exercise, and medications are effective on a day-to-day basis is to see whether fasting glucose levels are normal.

Patients taking fast-acting insulin need to check their blood glucose readings multiple times per day.

Screening for comorbidities

Even when well-controlled, having diabetes puts patients at risk of developing other diseases. Your family doctor will work with you to ensure that you receive adequate screening to identify and prevent complications from any of these other conditions. Screening includes:

• Routine blood pressure checks with a target of <130/80
• Dyslipidemia testing with a target LDL of <2.0 mmol/L (or 50% reduction from baseline)
• ECG every 3-5 years
• Monofilament/vibration testing annually
• Kidney function (both eGFR and ACR testing annually)
• Retinopathy screening every 1-2 years

Managing the risk of hypoglycemia

Patients using insulin or insulin secretagogues are at risk of developing hypoglycemia (low blood glucose), which is a potentially dangerous condition that affects mental functions. Patients should be aware of this risk and how to safely manage it.

Prevention

• Be aware that low blood glucose can happen
• Keep fast-acting sugar within reach, especially when driving
• Check blood glucose before driving and every 4 hours during long drives
• If driving, stop and treat if any symptoms appear
• After treating a low, wait until blood glucose rises above 5 mmol/L and symptoms have resolved before driving again
• Some patients are unaware of symptoms of hypoglycemia. Such patients must check their blood glucose before driving and every 2 hours while driving, or wear a real-time continuous glucose monitor

Managing the risk of dehydration

Some medications taken by patients with diabetes can be harmful if taken when significantly dehydrated. If a diabetic patient is sick (with vomiting or diarrhea), they should rehydrate appropriately and refrain from taking the "SADMANS" medications until they are well hydrated (having normal urine output again):

• S  sulfonylureas, and other secretagogues
• A  ACE-inhibitors
• D  diuretics, direct renin inhibitors
• M  metformin
• A  angiotensin receptor blockers
• N  non-steroidal anti-inflammatory drugs
• S  SGLT2 inhibitors

Sources:
Diabetes Canada Clinical Practice Guidelines