When May Insulin Pumps Be Useful in Diabetes Management?
Q: What are insulin pumps and how do they work?
A: Insulin pumps are small, portable, external electronic devices that deliver insulin to the body in a continuous fashion for basal needs and bolus doses for meal times and hyperglycemia correction. The amount of insulin delivery is programmed into the pump and the basal settings can be set to differ at different times to correlate with the patient’s individual needs. Patients then enter their blood sugars and a certain amount of insulin is calculated from preprogrammed settings. The insulin pump does not preclude a patient from checking his/her blood sugar. It is important that the patient understands that their blood sugar needs to be consistently monitored.
Q: What are the advantages of using an insulin pump?
A: Most patients enjoy the benefits of not having to inject themselves multiple times a day. The insulin pump uses rapid-acting insulin with the benefit of being able to precisely change doses with variable carbohydrate intake or for spontaneous events, such as exercise, changing work schedules, and other activities that may cause fluctuations in blood sugars. In addition, since this provides a continuous delivery of insulin, there is better overall compliance with less frequent hypoglycemia and glucose variability.
The advantages of continuous subcutaneous insulin with type 1 diabetes mellitus include superior glycemic control, lower insulin requirements, and better health-related quality of life/patient satisfaction.1 Most pump users only need to change their infusion site every 3 days. In addition, pumps have electronic calculators to determine “insulin on board time” in addition to mealtime and corrective insulin needs. This helps to reduce hypoglycemia by minimizing the effect of “insulin stacking” that results in inadvertent overdosing. The pump also offers easier tracking of insulin use as this is stored into the pump for easy review.
In a recently published study in Sweden involving 18,000 people with type 1 diabetes (2441 of which used insulin pump therapy and 15,727 who used multiple daily insulin injections [MDIs]), data showed lower cardiovascular mortality in those using an insulin pump as compared to MDI.2 Other studies have shown a reduced risk for retinopathy in those treated with insulin pumps as compared to MDIs and a reduced hemoglobin A1c in insulin pump users.3
Q: Who are good candidates to be referred for an insulin pump?
A: A clinician may refer a patient for insulin pump initiation after the patient has been determined to be a suitable potential candidate. Guidelines for patient selection are provided by the 2014 Insulin Pump Task Force Expert Consensus from the American Association of Clinical Endocrinologists.3
All patients need to have the ability to cope with the challenges of managing their diabetes. Persons with a significant “dawn phenomenon” may generally benefit from pump therapy, particularly those with type 1 diabetes who do not reach glycemic controls on standard MDIs, have labile diabetes, frequent severe hypoglycemia, and/or hypoglycemia unawareness.3
Persons with type 2 diabetes with suboptimal control on basal/bolus therapy may be good candidates if they have an irregular lifestyle and/or have severe insulin resistance.3 Select other patients, such as those with a history of pancreatectomy, should also be considered.
Q: Who are not good candidates for insulin pump use?
A: Patients who are unwilling to perform MDIs, frequently monitor their blood glucoses, or have reasonable motivation to achieve tighter glucose control are poorly suited for insulin pump therapy.3,4 Those with unrealistic expectations (eg, believing that pump therapy will relieve them of responsibility for self-care) and/or serious psychological or psychiatric conditions should be considered unsuitable for insulin pumps.3,4 Persons may also have concerns about pumps interfering with lifestyle, such as sexual activity or contact sports.3,4
Dr Carmichael discloses that he is on the speaker’s bureaus for Merck and Janssen that may be relevant to the content of this manuscript.
Victoria Bouhairie, MD, is a clinical fellow in the division of endocrinology, metabolism, and lipid research at Washington University School of Medicine in St. Louis, MO.
Kim A. Carmichael, MD, is an associate professor of medicine in the department of internal medicine in the division of endocrinology, diabetes, and lipid research at Washington University School of Medicine in St. Louis, MO.
References:
1. Pozzilli P. Continuous subcutaneous insulin infusion in diabetes: patient populations, safety, efficacy,and pharmacoeconomics. Diabetes Metab Res Rev. 2015 Apr 13 [epub ahead of print].
2. Steineck I, Cederholm J, Eliasson B, et al; the Swedish National Diabetes Register. Insulin pump therapy, multiple daily injections, and cardiovascular mortality in 18 168 people with type 1 diabetes: observational study. BMJ. 2015;350:h3234.
3. Grunberger G, Abelseth JM, Bailey TS, et al. Consensus statement by the American Association of Clinical Endocrinologists and the American College of Endocrinology insulin pump management task force. Endocr Pract. 2014;20(5):463-489.
4. Ross PL, Milburn J, Reith DM, et al. Clinical review: insulin pump-associated adverse events in adults and children. Acta Diabetol. 2015 Jun 12 [epub ahead of print].