Curbsiders

Podcast Recap | Curbsiders: CGMs, insulin, and how to adjust diabetes meds to glucose patterns

April 18, 2024

In this episode, Dr. Jeff Colburn, director of the Diabetes Center at the Richmond VA Medical Center, provides expert insights into CGMs, discussing the interpretation of blood sugar patterns and offering practical advice for addressing hypo- and hyperglycemic patterns. Their discussion highlights the evolving landscape of diabetes care, focusing on the complexities of CGMs and insulin pattern matching.

Podcast length: 1 hr., 10 min.

5 Key Takeaways

1. Broader eligibility for CGMs includes patients using daily insulin or experiencing problematic hypoglycemia.

Since April 2023, the Centers for Medicare & Medicaid Services (CMS) has allowed CGMs for patients with diabetes who either use insulin daily or experience problematic hypoglycemia. It's important to encourage regular follow-ups every 6 months to assess adherence to diabetes treatment. For patients with physiological frailties, aiming for A1C below 7% may not be safe; CGMs help in understanding the blood glucose pattern for tailored treatment. Studies indicate CGM use improves A1C levels even without treatment changes, mostly due to immediate feedback on eating habits.

In clinical settings, CGMs can be offered in two ways: through the CGM pro model, where the patient receives the sensor at the clinic and has no access to data, or the personal use model, where the patient wears the device and uses a smartphone app to record data. The Dexcom and Freestyle CGM models last for 10 days or 14 days, respectively, so order 2 or 3 sensors per month. Uploading the blood glucose data to the cloud aids monitoring by clinicians, caregivers, or family.

2. CGMs provide real-time glucose data, allowing for more precise management of blood glucose levels.

CGM measures time in range (TIR), which indicates how much time blood glucose stays in the ideal range of 70-180 mg/dL. Aim for the patient to be in the range at least 70% of the time. It's important to have less than 30% of the time with high blood glucose (>180 mg/dL) and less than 5% of the time with low blood glucose (<70 mg/dL). Encourage patients to journal their eating habits and physical activities for better understanding of glucose trends.

Unlike A1C, CGM’s TIR offers a more real-time view of glucose levels over the last 10 to 14 days. Additionally, CGM isn't affected by conditions like anemia that can impact A1C accuracy, and it tracks the variations that A1C would miss. However, acetaminophen, hydroxyurea or ascorbic acid can influence CGM data. A 15-minute delay in the CGM readings compared with actual blood glucose levels is likely, since CGM measures interstitial fluid glucose levels, and this can affect timely hypoglycemic treatment. Instruct patients to set alarms for low and high glucose levels based on their glucose levels and treatment regimen.

3. Evaluating blood glucose patterns involves addressing both hypoglycemia and hyperglycemia.

Start by addressing any hypoglycemia then treat hyperglycemia, targeting fasting glucose first and then addressing mealtime needs. Metformin and basal insulin primarily work to reduce fasting blood glucose levels. GLP1 agonists and SGLT2 inhibitors are effective at lowering both fasting and post-meal glucose levels.

Lowering the basal insulin dose is a potential treatment approach for nocturnal hypoglycemia. For patients on a sulfonylurea who report nocturnal hypoglycemia, choose to omit the evening dose, or discontinue altogether. Switching to a different drug class is also recommended, considering the lack of additional organ benefits with sulfonylureas. Adjusting insulin dose or consuming a protein-rich snack before exercise mitigates exercise-induced hypoglycemia, common in patients on insulin or insulin secretagogues.

To address fasting hyperglycemia, Dr. Colburn advises maximizing metformin dose or increasing basal insulin dose. GLP1 agonists and SGLT2 inhibitors can be included in the regimen. GLP1 agonists (including GIP/GLP1 agents), SGLT2 inhibitors, DPP4 inhibitors, or mealtime insulin can help with postprandial hyperglycemia, which is easily tracked by CGM. Addition of a GLP1 agonist or SGLT2 inhibitor (or both) to basal insulin and/or metformin reduces multiple daily insulin injections. In patients requiring mealtime insulin, the ‘basal plus one’ approach is helpful, where short-acting insulin is taken with the largest meal of the day instead of insulin at each meal.

4. Taking rapid-acting insulins between meals should be avoided.

Taking rapid-acting insulin between meals leads to ‘stacking’ doses. Instruct patients to adhere to the prescribed dosing schedules, like once daily basal insulin or taking rapid-acting insulin three times daily with meals. Patients should collaborate with their treating physicians to adjust the insulin doses based on CGM data.

5. CGMs enable precise medication modifications for optimal diabetes management.

Monitor for signs of overbasalization when prescribing basal insulin and evaluate requirements to escalate treatment beyond basal insulin. Insulin effectively lowers blood glucose; however, insulin initiation is often delayed due to clinical inertia. Adjustments can be made to insulin doses as glucose control improves, particularly after adding adjunct medications. Lifestyle modifications alongside medication management are essential for a comprehensive treatment approach to diabetes.

Any views, thoughts, and opinions expressed in this podcast recap are solely that of the hosts and guest and do not reflect the views, opinions, policies, or position of epocrates and athenahealth.

Source:

Watto, M. (2024, April 1). CGMs, Insulin, and How to Adjust Diabetes Meds to Match Blood Glucose Patterns. (No. 433) [Audio podcast episode]. The Curbsiders Internal Medicine Podcast. https://thecurbsiders.com/curbsiders-podcast/433-cgms-insulin-and-how-to-adjust-diabetes-meds-to-glucose-patterns