Does administering long-acting insulin (Lantus or similar) closer to bedtime improve morning blood glucose levels?

From the Guidelines

Administering long-acting insulin closer to bedtime is recommended to improve morning blood glucose levels, as it helps counteract the dawn phenomenon and provides a steady background level of insulin for approximately 24 hours. According to the most recent and highest quality study, 1, long-acting basal analogs, such as U-100 glargine and detemir, have been demonstrated to reduce the risk of level 2 hypoglycemia and nocturnal hypoglycemia compared with NPH insulin. The principal action of basal insulin is to restrain hepatic glucose production and limit hyperglycemia overnight and between meals.

Some key points to consider when administering long-acting insulin include:

• Starting with a conservative dose, often 10 units, and adjusting based on morning glucose readings
• Taking the insulin at the same time each night to maintain consistent coverage
• Being aware of the potential for overbasalization, which can be indicated by a high bedtime-to-morning glucose differential, hypoglycemia, or high glucose variability
• Monitoring for nighttime hypoglycemia and adjusting the dose as needed

It's also important to note that some people may experience better control with morning dosing, so it's crucial to work with a healthcare provider to determine the best timing for individual situations, as suggested by 1. Additionally, when switching from one basal insulin to another, doses can often be converted unit for unit, but an initial dose reduction of 10-20% may be necessary for individuals at high risk for hypoglycemia, as noted in 1.

From the FDA Drug Label

The safety and efficacy of once daily insulin glargine administered either at pre-breakfast, pre-dinner, or at bedtime were evaluated in a randomized, controlled clinical study in adult patients with type 1 diabetes (Study H, n = 378) In these patients, data are available from 8-point home glucose monitoring The maximum mean blood glucose was observed just prior to insulin glargine injection regardless of time of administration. The safety and efficacy of once daily insulin glargine administered pre-breakfast or at bedtime were also evaluated in a randomized, active-controlled clinical study (Study I, n = 697) in patients with type 2 diabetes not adequately controlled on oral anti-diabetic therapy. Insulin glargine given before breakfast was at least as effective in lowering HbA1c as insulin glargine given at bedtime or NPH insulin given at bedtime

Administering long-acting insulin (such as Lantus) closer to bedtime may have a similar effect on morning blood glucose levels as administering it at other times of the day, as the maximum mean blood glucose was observed just prior to insulin glargine injection regardless of time of administration 2.

• Key points:
  • The study found similar reductions in HbA1c with insulin glargine administered at pre-breakfast, pre-dinner, or bedtime.
  • The maximum mean blood glucose was observed just prior to insulin glargine injection, regardless of the time of administration.
  • Insulin glargine given before breakfast was at least as effective in lowering HbA1c as insulin glargine given at bedtime.

From the Research

Administering Long-Acting Insulin Closer to Bedtime

• Administering long-acting insulin, such as Lantus, closer to bedtime has been shown to improve morning blood glucose levels in patients with type 2 diabetes 3, 4, 5.
• A study comparing bedtime administration of insulin glargine to NPH insulin found that insulin glargine reduced fasting blood glucose levels more efficiently and with less nocturnal hypoglycemic events 4.
• Another study found that bedtime administration of insulin glargine resulted in lower morning glucagon levels and a more effective reduction of endogenous glucose production compared to NPH insulin 4.
• A randomized clinical trial comparing breakfast, dinner, or bedtime administration of insulin glargine in patients with type 1 diabetes found that all three administration times were effective in reducing HbA1c levels, but bedtime administration resulted in fewer nocturnal hypoglycemic events 6.
• A prospective study in patients with type 2 diabetes found that omitting breakfast and lunch after injection of different long-acting insulin preparations at bedtime resulted in comparable glucose target ranges at midnight and 07:00 hours, with no significant differences in glucose levels between the three insulin preparations 7.

Comparison to Morning Administration

• A study comparing morning versus bedtime administration of NPH insulin in patients with type 2 diabetes found that bedtime administration resulted in improved glycaemic control, with lower fasting plasma glucose and mean 24-hour plasma glucose levels 5.
• Bedtime administration of insulin was found to result in increased basal insulinaemia, leading to improved basal glycaemia and consequent improved overall metabolic control, compared to morning insulin administration 5.

Nocturnal Glucose Metabolism

• A study investigating nocturnal glucose metabolism after bedtime injection of insulin glargine or NPH insulin found that insulin glargine had a more effective reduction of endogenous glucose production in the morning, resulting in lower fasting glucose levels 4.
• The study also found that nearly 80% of the glucose-lowering effect in the morning was due to insulin glargine's reduction of endogenous glucose production 4.