Basal-Bolus Insulin Regimen in T2D

Submitted by Thiruvelan on Wed, 03/06/2013
Basal-Bolus Insulin Regimen in T2D

When blood-glucose control is inadequate despite treatment with a maximum dose of oral combination drug, the next step will be adding basal insulin therapy (once daily of long-acting insulin).

When should type 2 diabetes intensify their insulin therapy?

Typically, there is a progressive decline in beta cells in the case of type 2 diabetes. Thus once-daily basal insulin treatment may eventually fail to maintain blood-glucose control in a substantial number of type 2 patients. When you are not able to reach the A1C of 7 % then, treatment needs to intensify.

If you are in once-daily insulin therapy, next, you may include a second injection of basal insulin (twice-daily insulin therapy). If you are already in twice-daily insulin treatment, then basal-bolus therapy is considering as best in achieving more significant A1C reduction.

Adding Basal insulin along with Oral Drug

Every person is different, and his or her insulin requirement to is distinct; YMMV is an acronym stands for "Your Mileage May Varies." Thus, you should understand that the insulin dose that works best for you would not work the same way for someone else.

Titrate the insulin regimen is essential to achieve a target blood glucose level. It is to increase the dosage of the insulin by two units every 4 to 7 days until you reach your target, unless hypoglycemia may become your barrier.

Glargine or detemir (Levemir) insulin is the best choice in the treatment of diabetes type 2. If cost is the primary concern, then NPH, Humulin N, or Novolin N insulin once daily at bedtime or twice daily is a preferable alternative.

Addition of detemir, glargine, or NPH insulin once daily at bedtime along with oral medication resulted in similar improvement in A1C of about 1.5%. However, detemir & glargine had many advantages compared to NPH. Chances of hypoglycemia are 50 % lower, and lesser weight gain (detemir 0.7 kg, NPH 1.6 kgs in 20 weeks treatment).

Type 2 diabetes is a progressive condition; over time, patients on once-daily basal insulin often require multiple daily injections. For patients who take NPH at bedtime can additionally take another dose of NPH in the morning to manage pre-dinner hyperglycemia.

Adding basal insulin to oral therapy is adequate for most of the patients who are new to insulin. Some patients may need more, such as the addition of bolus insulin therapy (insulin before meals).

Basal-Bolus Insulin Regimens

Progression of diabetes type 2 may worsen insulin deficiency, and blood-glucose control becomes difficult (i.e., impossible to achieve the target). Now patients need to start rapid-acting insulin (regular, lispro, aspart) before meals (bolus therapy) in addition to once or twice-daily basal insulin therapy.

When do you include bolus regiment to your insulin treatment?

You should consider adding bolus insulin if the dosage of basal insulin has progressively inadequate in glycemic control and with frequent hypoglycemia. Or if the morning glucose level is within the target range, but inadequate control of A1C. It indicates there is no benefit in further increasing the basal insulin dose even if you do so; it leads to more hypoglycemia episodes. Now, this is the time to consider adding bolus insulin in your treatment to achieve the target A1C.

A basal-bolus regimen also has cost benefits. For example, a regimen of NPH and regular insulin (multiple daily injections or premixed) is significantly cheaper than various oral hypoglycemic agents.

Insulin dosage in your basal-bolus regiment

A basal-bolus regimen with 50% basal and 50% bolus seemed to provide better glycemic control. In the case of variation in glucose levels, inadequate control, or frequent hypoglycemia distribute total insulin spread equally before three meals.

Patients with mild stress and hyperglycemia should treat with a low dosage of insulin (0.2 units per kg). Elderly patients and people with renal or liver failure are at higher hypoglycemia risk, thus start with a lower dosage of insulin. Others can start with a dosage of 0.3 to 0.5 units/kg. Subsequently, titrating the dosage based on the blood-glucose level. Start the bolus insulin at a low dose; 4 to 6 units and gradually increase it.

You can add bolus insulin before breakfast if your prelunch glucose level is high. Before lunch, if your dinnertime blood glucose in high. Before dinner, if your bedtime blood-glucose level is high or a combination of these.

Further adjustments of the insulin dosage should make based on the blood-glucose levels before each meal and at bedtime. The bolus insulin dosage can be calculated based on the amount of carbohydrates in each meal, the insulin to the carbohydrate ratio as in the case of diabetes type 1. This method helps with fewer weight gains due to insulin treatment. You can reduce your bolus dosage if you expect to do exercise within 2 to 3 hours after the meals.

Simple premixed insulin therapy

Some patients may not be happy injecting them four or five times with the basal-bolus regimen. They may request a more straightforward treatment with three injections of premixed insulin per day, one before each meal.

Lispro mix (50% lispro and 50 % lispro protamine suspension) taking before each meal can help to attain A1C of below 7.5% as compared to basal-bolus regimen achieving a goal of A1C less than 7%. However, the hypoglycemic rate is similar in both cases. Thus pre-mixed insulin regimen with the lispro mix three times a day before each meal should have a relaxed A1C goal of less than 7.5%.

Biphasic insulin aspart is an aspart and protamine aspart mix. Three times a day, biphasic insulin aspart with each meal is comparable to the basal-bolus regimen in glycemic control and hypoglycemia episodes.

This simple premixed insulin regimen is a preferable option for a selected group of patients who do not like to adhere with a more complex basal-bolus insulin regimen.