What are the guidelines for managing Canadian Diabetes with Hemoglobin A1c (HbA1c)?

From the Guidelines

Clinicians should aim to achieve an HbA1c level between 7% and 8% in most patients with type 2 diabetes, as this target balances the benefits and harms of glycemic control, according to the American College of Physicians guidance statement 1.

Key Considerations

• The target HbA1c level should be personalized based on individual patient factors, such as age, duration of diabetes, risk of hypoglycemia, and presence of complications.
• For patients with a life expectancy less than 10 years, advanced age (80 years or older), residence in a nursing home, or chronic conditions, the goal should be to minimize symptoms related to hyperglycemia rather than achieving a specific HbA1c target.
• Clinicians should consider deintensifying pharmacologic therapy in patients who achieve HbA1c levels less than 6.5%, as the benefits of further glycemic control may not outweigh the risks of hypoglycemia and other adverse effects.

Benefits and Harms of Glycemic Control

• The evidence from clinical trials suggests that intensive glycemic control (HbA1c levels <7%) may reduce the risk of microvascular complications, but does not consistently show a reduction in macrovascular events or mortality.
• More intensive glycemic control is associated with an increased risk of hypoglycemia, weight gain, and other adverse effects.

Clinical Implications

• Clinicians should regularly review and adjust treatment plans to ensure that patients are meeting their individualized HbA1c targets, while minimizing the risk of hypoglycemia and other adverse effects.
• The use of generic medications and lifestyle modifications, such as diet and exercise, should be encouraged to achieve good glycemic control and reduce the risk of complications.

From the Research

Guidelines for Canadian Diabetes with HbA1c

• The optimal HbA1c target level for patients with type 2 diabetes is a subject of controversy, with different guidelines yielding differing recommendations 2.
• The American College of Physicians (ACP) recommends an HbA1c target level between 7% and 8% for most patients, while the American Diabetes Association recommends aiming for HbA1c levels less than 7% for many nonpregnant adults 2.
• A study found that patients who failed metformin monotherapy and received intensified treatment had a mean post-metformin HbA1c of 8.7% and a mean distance to goal of 1.7% 3.
• Another study compared the reduction of glycated haemoglobin (HbA1c) with sodium-glucose cotransporter type-2 inhibitors (SGLT2is) vs. dipeptidyl peptidase-4 inhibitors (DPP-4is) as add-ons to metformin in patients with type 2 diabetes mellitus (T2DM) 4.
• The study found that Δ HbA1c was slightly greater with SGLT2is (-0.80±0.20% from 8.03±0.35%) than with DPP-4is (-0.71±0.23% from 8.05±0.43%; P=0.0354) 4.
• When the mean baseline HbA1c was <8%, Δ HbA1c averaged -0.735±0.17% vs. -0.62±0.16% (P=0.0117) with SGLT2is vs. DPP-4is, respectively 4.
• However, this difference vanished when the mean baseline HbA1c was ≥8% (-0.87±0.22% from 8.27±0.32% with SGLT2is vs. -0.80±0.24% from 8.35±0.33% with DPP-4is; P=0.2756) 4.
• A comparative effectiveness and safety research study found that SGLT2i vs DPP-4i treatment initiators had a reduced risk of modified MACE and HHF, an increased risk of genital infections and DKA, and a lower risk of AKI, regardless of baseline HbA1c 5.
• The study also found that treatment with SGLT2i showed an increased risk of genital infections and DKA and a reduced AKI risk compared with DPP-4i, with no evidence of treatment effect heterogeneity across the HbA1c levels 5.

Treatment Options

• SGLT2 inhibitors and DPP-4 inhibitors are two treatment options for patients with type 2 diabetes who have not achieved glycemic control with metformin monotherapy 6.
• SGLT2 inhibitors have additional benefits, including weight loss, blood pressure reduction, cardiovascular risk reduction, and renoprotective effects, but also have an increased risk of urogenital infections and possible risk of "euglycaemic" diabetic ketoacidosis 6.
• DPP-4 inhibitors are weight neutral and have few adverse effects, but may not have the same level of cardiovascular benefits as SGLT2 inhibitors 6.
• The choice between SGLT2 inhibitors and DPP-4 inhibitors should be based on individual patient profiles, including factors such as weight, blood pressure, and cardiovascular risk 6.