Pattern Adjustment MDI

Adjusting Insulin (MDI): based on blood glucose patterns

If your T1D child's blood sugar swings wildly, or is low at the same time each day (or high!) you may need to adjust insulin doses. But which dose, and how much? Looking for patterns in the numbers in your child's log book is a great place to start. Here we give you 3 easy steps for adjusting insulin within a Basal-Bolus/MDI Program (using long-acting for background insulin + rapid-acting insulin for food). We'll show you what to look for and how to tweak things from there.

Before Reading This Article...

If you have not done so already, we recommend that you first read How Insulin Action Impacts Blood Glucose in an MDI Program as background information for what follows.

Pattern Adjustment in 3 Easy Steps

In order to detect a pattern of high or low blood glucose, it is necessary first to know your child’s target blood glucose. Once you know what the goal is, you are ready to start down the path to reach that goal.

It may seem a little intimidating to make changes to the insulin doses your child is receiving. However, if you choose to make insulin adjustments, the process is relatively straightforward:

Waltzing The Dragon Inc

1. Review the log book every 3 to 4 days, looking for patterns.

2. If blood glucose is below the target range at the same time of day, for 2 days in a row...

... you may need to decrease the insulin that is working at that time.

  • It is wise to adjust first for low blood glucose. This is because lows (especially severe lows) present a greater health risk in the short term, so they warrant priority in terms of managing blood glucose. In addition, lows can cause later highs, so correcting the lows may also correct for some highs.
  • Once you have low blood glucose under control, then you can address the remaining highs.
  • If there are 3 or more lows per week, but no pattern, contact your diabetes health care team for guidance.

3. If blood glucose is above target at the same time of day, for 3 days in a row...

... you may need to increase the insulin that is working at that time.

  • It helps to make changes to only one insulin dose at a time, and then “try out” that change for 2 to 3 days before increasing the same dose again or making changes to other doses. This gives you a chance to assess the effects of the change.
  • If there is more than one time of the day when blood glucose tends to be high, it may be most effective to start by adjusting for the earliest one. This may resolve the problem of highs later in the day, too. For example, if blood glucose pattern is above target at both lunch and supper, it is wise to first adjust for the lunch highs, that is, by increasing the morning rapid-acting insulin (Humalog®, NovoRapid®, Apidra®).
  • If blood glucose readings are high across the whole day, it may be most effective to start by adjusting for the morning blood glucose first (by increasing the daily dose of Lantus® or Levemir®). Make additional changes only after you have had a chance to see the effect this has on readings for the rest of the day.
  • If you correct high blood glucose often (using a “correction formula” or “sliding scale”), this may be an indication that you need to do a pattern adjustment to increase the insulin that is responsible for the high at that time. For example, if you are always giving rapid-acting insulin at supper to correct high blood glucose, then you may need to fix “the problem” by increasing the lunchtime rapid-acting insulin.

More about Highs:

More on Correction Formulas + Sliding Scales:

By How Much Should I Adjust?

The amount that you change the dose depends on how much insulin is currently being given.

less than 5 units then adjust by 1/2 unit
5 - 15 units then adjust by 1 unit
16 - 30 units then adjust by 2 units
greater than 30 units then adjust by 3 - 4 units

Tip from the Trenches

We have found that a pattern of highs or lows “jumps out” at us if we use a colour coded system in the log book: when we write in a high reading, we use red ink; low readings are logged in blue; target readings are written in black. Rather than keeping 3 pens hanging around, consider buying a pen with 4 colours in one barrel (Bic makes one). Or trying using pink and blue highlighters to draw attention to high and low readings. ~Michelle and Danielle

Other Notes about N/NPH Pattern Adjustment:

  • Before adjusting insulin, consider the other factors which may affect blood glucose, such as: exercise, food, time between finishing the meal/snack and checking blood glucose (at least 2 hours is needed), falsified results, inaccurate readings due to not washing hands, etc. It’s possible that no changes are needed to the insulin dose if these other factors are accounted for.
  • If blood glucose readings do not end up in the target range after following the above steps 2 or 3 times, consult with your child’s diabetes health care team for guidance.
  • Be Aware of Night-time Lows:
    • Your review of the log book may not directly show night-time lows. However, high morning readings may, in fact, be an indicator of undetected overnight lows: your child may drop low in the middle of the night, causing the liver to release a large amount of glucose to treat the low, resulting in a high morning reading.
  • If breakfast/waking blood glucose readings are above 14.0 mmol/L, it is wise to first rule out night-time lows. Set your alarm and check blood glucose at 3 a.m. for two nights.
    • If the blood sugar is low, you may choose to decrease the bedtime Lantus®/Levemir.®
    • If blood glucose highs are not due to a low followed by a rebound, your child may need more insulin overnight. In this case, you may choose to increase the bedtime Lantus®/Levemir.®
  • If you have reason to suspect undetected night-time lows, you may need to check your child’s blood glucose more than once, and at different times, during the night to make sure you aren’t missing a low. Another option is to use a Continuous Glucose Monitor (CGM), which will provide a visual of blood glucose trends during this time, and which you may program to provide an auditory alarm if your child’s blood glucose goes below a specified threshold.

More detailed information + practice exercises:

An excellent Insulin Adjustment resource that we would encourage you to visit is provided online by BC Children’s Hospital: an insulin adjustment self-learning program is provided in a series of modules which take you through the principles and process of Insulin Dose Adjustment, covering all the relevant background information, as well as that specifically relating to pattern insulin adjustment (in Modules 1 and 2).


The above information was adapted with permission from The Alberta Children’s Hospital Diabetes Clinic information handouts.

The above information was reviewed for content accuracy by clinical staff of the Alberta Children’s Hospital Diabetes Clinic.