Insulin pump therapy explained

Insulin pump therapy explained

Insulin pump therapy is a method used in type 1 diabetes for administering insulin. Conventionally, insulin was delivered via a subcutaneous injection. However, as technology has advanced, insulin pumps allow patients to administer their insulin via a cannula, which remains attached to the body.

How insulin pump therapy works

Normally, people with type 1 diabetes use 2 types of insulin. They use a long acting insulin, which helps to prevent the liver releasing too much glucose. They also use a rapid acting insulin, which helps prevent glucose spikes after eating. Therefore, rapid insulin is administered with food.

An insulin pump only uses rapid insulin. Between meals, very small amounts of insulin a dripped into the body every minute to act as the long acting insulin. This is called their basal rate. The amount that is dripped in can vary depending on the pump settings. In fact, this is one of the first major differences between insulin pump therapy and injection therapy. If injecting insulin via the conventional method, patients have no flexibility to modify their dose once the insulin is administered.

However, in insulin pump therapy, patients can adjust this basal rate based on their glucose requirements. For example, if you’re prone to high glucose upon waking, you have the flexibility to increase your basal rate for a specific time block and lower it again as needed.

You then administer extra insulin with meals as needed.

How do I get an insulin pump?

There is a specific criteria to be put forward for insulin pump therapy. The main consideration your team will want to see is that you are engaged with your management. An insulin pump is only a tool to help you manage your diabetes and a good tool it is. However, it does not do it for you.

Therefore, your diabetes team will want each patient put forward for insulin pump therapy to have completed type 1 diabetes education. They will also want patients to know how to carbohydrate count and to have regularly attended their diabetes appointments.

Insulin administeration

Insulin pumps come in 2 main formats. Normally, the cannula is inserted into the skin around the belly area. This is connected to some tubing, which is connected to the pump itself. The pump then speaks to the handset that the user can use to adjust their settings accordingly. This type of pump needs to remains on the persons body at all times because it is attached to the cannula. For example, some patients put it in their pocket or bra strap.

Newer versions of insulin pumps, now use tubeless technology. The insulin giving set is still attached to the body but all the insulin is inserted within the device. This means there is no tubing, which is preferable for many pump users.

Benefits of insulin pump therapy

There are many benefits over conventional subcutaneous injection. Let’s examine some of these.

Adjusting basal rate

Pump users have the luxury to adjust their basal rates throughout the day. For example, if you’re particularly active at work, you can lower your basal rate during this time period only to increase it once you become more idle later in the day.

Another example is when trying to combat an early morning rise in your glucose levels. This is called the dawn phenomena. Without a pump, the best patients can do is administer a correction dose upon waking.

With the pump, they can pre set an increase in their basal rate to compensate for the glucose rise caused by the dawn phenomena.

Your diabetes team will work with you to calculate your hourly rates based on your routine.

Pre sets

You can also insert pre set rules into your pump and activate these as needed. For example, you may have basal rates for work and non work days.

You may have rules for exercise or any other life event that requires more or less insulin.

Temp basal rates

In addition to loading hourly basal rates, you have the flexibility to temporally override this by increasing or decreasing your basal rate by a set percentage.

Two of the most common examples of this are when you are sick or exercising.

Different bolus options

As with the basal insulin, pump users have more flexibility with how their meal time insulin is administered. With subcutaneous injections, patients are limited to how that insulin enters the body. Typically, this takes 30 minutes to enter the body, 1 hour to reach peak action and 4-5 hours to completely leave the body.

This can make timing of the insulin injection tricky, especially with fast or slow releasing meals.

Pump users can adjust how the bolus insulin is delivered based on their needs. For example, they have the option to add their basal rate onto their bolus injection to allow extra insulin to quickly enter the body. This helps to prevent spikes from very high glycaemic index meals (if you’re unfamiliar with glycaemic index, we’ve blogged about this here). This is called a super bolus.

Conversely, pump users can also delay the release of their rapid insulin to help digest particularly slow releasing meals. Meals, such as curry and pizza, can take a long time to be digested and absorbed into the body. This is because of the fat content of these meals. To help combat this, patients using subcutaneous injections would need to split their dose. This is usually administered before and after the meal. Of course, this means more injections for the patient.

However, insulin pump users have the option to use extended boluses. This releases their insulin over a longer period to help digest and absorb low glycaemic index meals.

There are also other options which use a combination of the above methods. Nonetheless, the pump makes insulin administration much more flexible.

Negatives of insulin pump therapy

Like anything, there are drawbacks. Some patients do not like the idea of having to wear the pump on them all the time. Particularly, those using pumps with tubing.

Another draw back is pumps require quite a lot of work to make sure they work correctly. The common misconception of insulin pumps is that the device manages your glucose for you. This is unfortunately not the case. The user needs to engage with the pump and tell it what you are doing.


There are also incidents of pumps blocking or becoming disconnected. If patients realise this has happened, it is a simple case of replacing the cannula and tubing. However, for those that do not notice, this can become serious and they may begin to generate ketones. If you’re unfamiliar with ketones we’ve previously blogged on this here. If left unnoticed, you can become very unwell and if left untreated, this would become fatal. Though, death is rare in the modern era.

Pumps can also make it difficult around exercise. For non contact sport or non swimming based activities, this is fine. However, if the pump is likely to become knocked or wet, it will likely need to be disconnected temporarily. They can only be disconnected for a limited time before the patient would need to return to subcutaneous injections for a short while.

Rapid insulin administeration

Administering any rapid insulin over 6 units can lead to the tubing blocking. Therefore, pump users will be advised to extend their bolus insulin if requiring over 6 units. This can make controlling high glycaemic meals tricky because the insulin is unlikely to enter your circulation before the food. This can result in a glucose spike between meals.

Is an insulin pump for me?

Ultimately, only you can make this decision. Speak with your diabetes team for more information. There is no pressure either way and you need to do what is best for you.

Need more help

If you need more support we offer a range of 1:1 consultancy services and online programmes focused on helping you improve your glucose control and health for the long term. These include our type 2 diabetes recovery programme, type 1 glucose stability programme and winning weight loss programme. Go to the pages using the links above or in the headers or get in touch if you have questions.