woman getting blood sugar read by doctor
Sliding scale insulin therapy is almost exclusively used in healthcare settings like the hospital.
FatCamera/Getty Images
  • Sliding scale insulin therapy uses your pre-meal blood sugar level to determine insulin dosage.
  • Research indicates sliding scale insulin therapy is ineffective at managing blood sugar levels.
  • Therefore, try an alternative method like insulin pumps or once-weekly injections.
  • Visit Insider's Health Reference library for more advice.

Of the more than 30 million Americans with diabetes, about 7.4 million use one or more forms of supplemental insulin to help keep their blood sugar levels within a certain target range.

Insulin therapy is an important part of treatment for people living with diabetes. Sliding scale insulin (SSI), once a prominent diabetes treatment, entails checking your blood sugar levels before meals. Your pre-meal blood sugar then determines your insulin dosage.

While sliding scale insulin therapy is still used today in the hospital setting, the approach has become increasingly controversial as more research has revealed that it can fail to improve blood sugar control.

Using the right amount of insulin is crucial because too little causes persistently high blood sugar, which can damage the heart, eyes, kidneys, nerves, and blood vessels, says Patricia Peter, MD, Yale Medicine endocrinologist. Meanwhile too much causes low blood sugar, which leads to hunger, irritability, seizures, and even comas.

How sliding scale insulin therapy works

SSI therapy requires checking your blood glucose levels about four times a day before each meal. The higher your blood sugar, the more insulin you'll likely need to take to get your blood sugar levels back to a normal range, hence the name "sliding scale."

A sliding-scale insulin regimen typically involves these steps:

  1. Check blood glucose levels with a glucometer 15 minutes before a meal and 15 minutes before bedtime.
  2. If your glucose is elevated above 150 mg/dL, you'll take a certain number of insulin units on the sliding scale you were prescribed by your doctor. Typically, this will mean taking 1 to 3 units of insulin for every 50 mg/dL above 150 on your glucometer reading, says Cardillo.
  3. Even if your pre-meal blood glucose is within a normal range, aka less than 140 mg/dL, you may still need to administer a dose of rapid-acting insulin, according to Cardillo. Rapid-acting insulin begins working within 15 minutes and lasts for two to four hours. This could be a specific prescribed dose, such as taking 5 units with each meal, or a flexible dose based on the number of carbohydrates you'll be eating, such as 1 unit per every 15 grams of carbs.

Here's a sample chart for sliding-scale insulin, per the University Medical Center pharmacy:

Blood glucose (mg/dL)

Low dose: For highly insulin-sensitive patients

Moderate dose: For patients with normal insulin sensitivity

High dose: For highly insulin-resistant patients

Less than 70

Follow HYPOglycemia Guidelines

Follow HYPOglycemia Guidelines

Follow HYPOglycemia Guidelines

70-139

0 units

0 units

0 units

140-180

2 units

3 units

4 units

181-240

3 units

4 units

6 units

241-300

4 units

6 units

8 units

301-350

6 units

8 units

10 units

351-400

8 units

10 units

12 units

Higher than 400

Administer 10 units, notify your provider, and check blood sugar again in 30 minutes. Continue to take 10 units and do blood sugar checks every 30 minutes until blood glucose is less than 300 mg/dL.

Administer 12 units, notify your provider, and check blood sugar again in 30 minutes. Continue to take 10 units and do blood sugar checks every 30 minutes until blood glucose is less than 300 mg/dL.

Administer 14 units, notify your provider, and check blood sugar again in 30 minutes. Continue to take 10 units and do blood sugar checks every 30 minutes until blood glucose is less than 300 mg/dL.

Disadvantages of sliding scale insulin

SSI is often implemented in hospitals where it's unclear how much the patient needs, says Kasia Lipska, MD, a Yale Medicine endocrinologist. This is because unlike fixed-dose insulin regimens - which involve taking the same amount of insulin at every meal - SSI allows healthcare providers to continually tweak the insulin dosage based on the patient's pre-meal blood sugar.

However, sliding-scale insulin has still started to fall out of favor for a variety of reasons, such as:

1. Ineffective blood sugar control

Some studies found SSI often causes fluctuations in blood sugar levels. This is because many scales are designed to only correct high pre-meal blood sugar levels, and may not account for them rising further after a meal, according to Peter.

In fact, a small 2006 study found 84% of administered SSI doses failed to correct excess blood sugar in hospital patients, and a 2015 meta-analysis found the use of SSI frequently led to high blood sugar.

Additionally, if you skip a meal or are simply more sensitive to insulin on a particular day, the doses on your sliding scale might be excessive, which can then lead to a dangerous drop in blood sugar. Hence why a 2012 study found sliding scale insulin therapy can cause unpredictable drops in blood sugar levels.

2. Frequent blood sugar checks

People using SSI need to check their blood glucose levels four or more times a day depending on their meal schedule.

"There are lots of other diabetes medications available, such as pills and weekly or daily injections, that would not require as many blood sugar checks and may lead to similar or better overall blood sugar control than the sliding scale," says Peter.

3. Strict diet

With SSI, you need to eat your meals at roughly the same times each day and keep your carb intake consistent in order for the treatment to be effective. Otherwise, your SSI chart may not be as accurate.

You should also avoid variations in activity levels with SSI, as this can affect your insulin demands.

4. Lacks personalization

One of the major criticisms of SSI is that it fails to take a patient's weight, activity levels, stress levels, and other key fluctuating factors into account that may influence their insulin needs.

Insider's takeaway

As early as the 1930s, SSI was considered standard practice - but as increasing research has revealed a greater understanding of insulin therapy, more efficient and effective methods have emerged.

Due to the aforementioned drawbacks, SSI is now primarily administered for hospitalized diabetes patients whose insulin requirements are either unclear or in flux, says Lipska.

In fact, the American Academy of Family Physicians recommends using basal-bolus insulin injections instead of SSI, as this approach keeps blood glucose levels more steady throughout the day.

Keep in mind that diabetes treatment is not one-size-fits-all, and your healthcare provider can come up with a plan that addresses your specific needs.

How to reverse insulin resistance through diet and a 7-day meal plan to get you startedHow to recognize the symptoms of hypoglycemia, or low blood sugarThe most common signs and symptoms of hyperglycemia, or high blood sugarWhat is diabetes? A comprehensive guide to lower blood sugar and manage the condition

Read the original article on Insider