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Basal Insulin Case 2

CE / CME

The Role of Basal Insulin in the Modern Era of Diabetes Management: Interactive Case Challenge 2

ABIM MOC: maximum of 0.75 Medical Knowledge MOC point

Physician Assistants/Physician Associates: 0.75 AAPA Category 1 CME credit

Nurses: 0.75 Nursing contact hour

Physicians: maximum of 0.75 AMA PRA Category 1 Credit™

Released: October 26, 2023

Expiration: October 25, 2024

Steven V. Edelman
Steven V. Edelman, MD
CME/CE Information

Activity

Progress
1
Course Completed

Discussion
The ADA 2023 Standards of Medical Care in Diabetes and the European Association for the Study of Diabetes recommend adding insulin when an individual’s prescribed A1C targets are not met with other treatment strategies.1,2 When discussing insulin therapy with the patient and to help with patient-specific needs, a thorough education about diet, blood glucose monitoring, and how to avoid and appropriately treat hypoglycemia will provide patients with needed information to reach their goals. 
If the patient’s A1C is greater than 2 percentage points above the goal, the ADA recommends that in addition to the patient’s current pharmacologic therapy, basal insulin initiation should be started with a conservative dose (based on body weight) of 10 units/day or 0.1-0.2 units/kg/day at bedtime. Basal insulin curbs hepatic glucose production and reduces hyperglycemia between meals and overnight.1 It also is useful for patients who have not met their glycemic goals with oral therapies and are not good candidates for GLP-1 receptor agonists. Longer-acting insulin analogues also offer more flexibility in the timing of insulin injection. Available bolus and basal insulins are listed in the table below. 

Basal and Bolus Insulins in 20233-11 

The key to success is frequent follow-up after insulin initiation to avoid “failure.” Have the patient follow a self-titration regimen and return to clinic or schedule a follow-up appointment (by phone, email, telehealth, etc) relatively soon. Limit self-monitoring of blood glucose to only once per day in the morning, but check at bedtime periodically to make sure the patient does not need predinner fast-acting insulin.11,12 

The many benefits of the basal insulins U-300 glargine and degludec in type 1 and type 2 diabetes include less intrasubject variability, less hypoglycemia, less weight gain, easy-to-use pens, and a flat, stable, and prolonged action of >24 hours.12,13 Patients should be informed that it takes 4-5 days to reach equilibrium, and they can expect temporarily elevated blood glucose and may need correction doses. This is important, as patients may think the insulin is not working for them and stop it. One-to-one conversion from a prior basal insulin dose is suggested, but some earlier studies found that when a patient switches from U-100 glargine to U-300 glargine, a 10% to 15% higher dose with the U-300 glargine may be needed.  

Simple Daily Self-Titration Option 

Gerstein and colleagues14 found that encouraging patients with type 2 diabetes to practice self-titration when starting insulin resulted in more patients safely attaining their blood glucose goals. In this study, patients took evening glargine with self-titration by 1 unit/day if the FBG was >5.5 mmol/L. Patients must be able to self-monitor their FBG once per day. Self-titration by increasing the insulin dose by 1 unit every night until FBG target is reached is recommended by Diabetes Canada.15 This is an attractive option for patients because it is typically easier for them to titrate daily vs twice weekly. Titrations and getting to the goal can be done in days to weeks. 

Hypoglycemia

Beyond achieving blood glucose goals, self-titration can be further individualized according to caution for hypoglycemia and by adjusting the ranges of where patients would adjust their insulin. The titration parameters can be changed again once patients have made the insulin adjustments. In the case challenge, the patient reported weekly episodes of hypoglycemic symptoms at various times throughout the day—and this was despite a fairly well-controlled FBG of 133 mg/dL after titrating her degludec to 38 units at bedtime, in addition to her other medications. Because she was unsure of the cause and suspected delayed or missed meals, she was instructed to keep a log of hypoglycemic events. By using this tool, she recognized that her hypoglycemia symptoms occurred as a result of delayed meals, and she was able to correct by adjusting her mealtimes. If no attributable cause is found, it would then be reasonable to reduce degludec by 4 units or 10% to 20%. 

Pitfalls in Initiating/Titrating Basal Insulin  

Common pitfalls in initiation and titration of basal insulin include titrating too slowly after starting insulin and failure to monitor bedtime glucose, which can result in overbasalization. The ADA 2023 guidelines describe the clinical signs of overbasalization as: basal insulin dose more than approximately 0.5 units/kg, a bedtime–morning glucose difference of ≥50 mg/dL, hypoglycemia (aware or unaware), and excessive variability.1,16 Not being aware of high blood glucose at night that contributes to high morning blood glucose will result in patients continuing to increase their insulin dose and subsequent overbasalization. This also can put patients at increased risk for hypoglycemia if their diet or routine changes. This scenario can be avoided with occasional paired testing of bedtime and morning blood glucose.11 More conversations with patients may be necessary to further individualize their therapy.16

Summary 

Basal insulin remains a good option for many patients with type 2 diabetes who have not reached glycemic goals with other therapies. Longer-acting basal insulin, such as degludec and U-300 glargine, may have additional benefits compared with shorter-acting basal insulins or first-generation insulins. When initiating basal insulin, follow up frequently to avoid insulin failure, and provide instructions for patients’ self-titration of their own insulin to achieve their goals more quickly—and keep an eye on that bedtime blood glucose.