Insulin pump therapy in SA

Dr Louise Johnson gives us a breakdown of the insulin pump therapy available in South Africa.


Diabetes is rapidly becoming a major health epidemic in most regions of the world. All Type 1 diabetes patients and a significant number of Type 2 diabetes patients require the use of insulin for controlling blood glucose.

There are several varieties of insulin and many different injection regimes that can be used. Despite the availability of insulin vials and pens, the acceptability for patients and the glucose readings that are obtained with single or multiple injections regimens is not to the desired level.

This is where insulin pump therapy also known as continuous subcutaneous insulin infusion (CSII) comes in.

Continuous subcutaneous insulin infusion

Insulin pumps were introduced half a century ago. They utilise short- or rapid-acting insulin types only. This minimises variability of administration and reduces the chances of glucose fluctuations. Pump therapy has progressed to the level of mimicking physiological demands.

Pumps are programmed to deliver basal or background insulin. This is usually the same as the previous long-acting insulin. Basal insulin delivery happens automatically. It delivers a programmable dosage per hour every 24 hours; it’s tailored according to the glucose profile of the person.

The insulin requirements may be affected by a person’s physiology, exercise, work schedule, concomitant medications, and illness.

Most patients utilise multiple basal rates over a 24-hour period. There are some that only uses one rate. Most pumps have the capability of programming basal rates that can be used in special situations as a temporary basal rate. Your physician will determine all this.

There is also a bolus function. This is calculated according to the carbohydrate ratio used for carb counting. The person should administer the correct amount of total carbohydrates consumed to the pump and it will then automatically calculate the exact number of insulin and deliver it. This will be administered over minutes to a few hours. Insulin boluses cover meals and correct high blood glucose levels.

How is insulin delivered?

This happens via a plastic cannula connected to the pump on the one side and a single subcutaneous site with a connection on the other side.

The subcutaneous site is the same as a person would inject insulin in the fat tissue on the abdomen. The site needs to be changed every three to four days to prevent infection or inflammation.

Only rapid-acting insulin can be put into a pump. Usually the analogues work best (Novorapid, Humalog and Apidra).

Advantages

  1. Programmable insulin delivery allows closer match with physiologic needs.
  2. Uses only short- or rapid-acting insulin. This minimises peaks and absorption related variability.
  3. Use one injection site every three to four days. This reduces variation in absorption and treatment burden from multiple injections.
  4. Reduction in glucose variability and improve glucose control.
  5. Decrease the risk of severe hypoglycaemia
  6. Improved quality of life and treatment satisfaction.

Type 1 ideal candidate

The ideal candidate for initiation of pump therapy is a motivated patient who is knowledgeable in the important aspects of diabetes self-care and desires better glucose control.

The patient should be familiar with carbohydrate counting and have knowledge about pump technology.

However, a pump is neither a cure for diabetes nor does it function autonomously without intervention or input.

Patients should be clear about the fact that the pump is a highly-specialised gadget. It requires constant interaction from the wearer.

It’s important to regular monitor blood glucose and communicates with a professional pump team. This will predict long-term success.

Indications for insulin pump therapy

  1. Suboptimal glucose control despite multiple daily injections. You do not reach your target HbA1c.
  2. Frequent or unpredictable hypoglycaemia and hypoglycaemia unawareness.
  3. Dawn phenomenon. That is the early rising of blood glucose between 2am and 8am.
  4. An active lifestyle with strenuous physical activities.
  5. Children and young adults who typically desire fewer restrictions and more flexibility.
  6. Growth spurt of adolescents.
  7. Preconception planning and pregnancy
  8. The presence of gastroparesis. (Abnormal slow movement of food from stomach to the rest of the bowel).
  9. Hectic lifestyle with frequent travel between time zones.
  10. Shift work.
  11. Need for flexibility in the amount and timing of meals.
  12. Patients that are sensitive to insulin and need very small dosages.
  13. Type 2 diabetes patients with increased insulin requirements.

Types of pumps in South Africa

We currently have three different companies with have a variety of pumps. Each have its own pros and cons. It’s important that your medical team is familiar with your pump. Medical aids sometimes prefer to pay for certain pumps.

Medtronic 780 G is the newest of the Medtronic pumps and is a hybrid close loop system.

Tandem T slim 2 is the newest of the Tandem pumps and is also a hybrid close loop system pump.

Roche Accucheck Combo is a traditional pump.

Understanding hybrid close loop pump systems

In this type of system, the insulin pump “talks” to a continuous glucose sensor. The pump has a built-in algorithm; this allows the insulin to increase or decrease according to the blood glucose to attain the target. The only interaction the patient has with the pump is the input of carbohydrates consumed. Currently this is the ‘top’ pump to have if possible.

Disadvantages

  • Pumps are technology and they can break or malfunction
  • Cannulas can kink and this will stop insulin delivery.
  • Infusion sites can get infection or inflammation. This will cause rapid development of extreme hyperglycaemia, especially in Type 1 diabetes patients.

Pumps are not yet perfect but they are very close to it. Safeguards, such as alarms that warn of delivery problems or low amount of insulin in the pump reservoir are now standard features of insulin pump.

Dr Louise Loot

MEET THE EXPERT


Dr Louise Johnson is a specialist physician passionate about diabetes and endocrinology. She enjoys helping people with diabetes live a full life with optimal quality. She is based in Pretoria in private practice.