Can I discontinue insulin therapy once my Hemoglobin A1c (HbA1c) improves?

Can Insulin Be Discontinued Once HbA1c Improves?

Yes, insulin can and should be discontinued or de-intensified when HbA1c improves to less than 6.5%, as continuing treatment below this threshold increases risks of hypoglycemia, weight gain, and mortality without providing additional clinical benefit. 1

When to Consider Insulin Discontinuation

HbA1c Below 6.5%

• Clinicians should actively de-intensify pharmacologic therapy when HbA1c falls below 6.5% by reducing insulin dosage, removing insulin if the patient is on multiple medications, or discontinuing pharmacologic treatment entirely 1
• The ACCORD trial, which targeted HbA1c <6.5% and achieved 6.4%, was stopped early due to increased overall mortality, cardiovascular deaths, and severe hypoglycemic events 1
• No trials demonstrate that targeting HbA1c below 6.5% improves clinical outcomes, while the harms are substantial 1

HbA1c 6.5-7.0%

• For patients achieving HbA1c in this range, consider reducing insulin doses or transitioning to non-insulin agents, particularly if glycemic control was achieved through lifestyle modifications 1
• Metformin can often be continued at lower HbA1c levels as it does not cause hypoglycemia, is well-tolerated, and low-cost, though the benefit diminishes below 7% 1

Common Clinical Scenarios for Insulin Discontinuation

Improved Glycemic Control

• The most common reason for insulin discontinuation in real-world practice is achieving improved blood glucose control (33.2% of cases) 2
• Weight loss achievement accounts for 18.5% of insulin discontinuation decisions 2
• Initiation of newer non-insulin diabetes medications (GLP-1 receptor agonists, SGLT-2 inhibitors) accounts for 16.7% of discontinuation decisions 2

Transition to Oral Agents or GLP-1 Receptor Agonists

• When HbA1c improves on insulin, consider transitioning to GLP-1 receptor agonists, which can provide equivalent or superior glycemic control without the weight gain and hypoglycemia risk associated with insulin 3
• Studies show that GLP-1 receptor agonists (exenatide QW, liraglutide, dulaglutide) achieve similar or better HbA1c reductions compared to insulin glargine, even at baseline HbA1c levels of 10-11% 3
• Combination therapy with metformin plus other oral agents (DPP-4 inhibitors, SGLT-2 inhibitors, thiazolidinediones) can reduce HbA1c by 2-3% from baseline levels of 9-11% 3

Important Caveats and Pitfalls

Do NOT Discontinue Insulin If:

• The patient has Type 1 diabetes - insulin is always required 1
• Severe hyperglycemia persists (HbA1c >10%, symptomatic hyperglycemia, weight loss, ketonuria) - insulin remains the preferred treatment 1
• The patient is hospitalized or acutely ill - insulin is typically required during metabolic decompensation 4
• Pregnancy or severe organ dysfunction (hepatic/renal impairment) is present - insulin may be the safest option 4

When Discontinuing Secretagogues with Insulin:

• If a patient is on both insulin and sulfonylureas/meglitinides, discontinue the secretagogue first when de-intensifying therapy 1, 5
• Continuing secretagogues with basal insulin results in significantly more hypoglycemia and weight gain compared to using insulin with metformin alone 5
• Patients who stop secretagogues when starting insulin require higher insulin doses (0.8 vs 0.6 U/kg/day) but experience less hypoglycemia 5

Monitoring After Discontinuation:

• Reassess HbA1c every 3 months after any medication change to ensure glycemic targets are maintained 1, 6
• Continue lifestyle interventions (diet, exercise, weight management) as these may allow sustained glycemic control without pharmacotherapy 1
• Consider that 42% of patients discontinue insulin within 12 months in real-world practice, most commonly under physician guidance due to improved control 2

Special Populations Requiring Different Targets

Elderly or Limited Life Expectancy (<10 years):

• Focus on minimizing hyperglycemic symptoms rather than targeting specific HbA1c levels in patients ≥80 years, nursing home residents, or those with advanced comorbidities 1
• Target HbA1c of 7.5-8.5% is more appropriate than aggressive control, as harms outweigh benefits in this population 1, 6

Patients with Endocrinology Follow-up:

• Patients seeing endocrinologists are 2.6 times more likely to have insulin appropriately discontinued when indicated (OR 2.6,95% CI 2.2-3.0) 2
• Consider endocrinology referral if uncertain about insulin discontinuation decisions 1