A 76-year-old female with a history of type 2 diabetes mellitus (DM), hypertension, peripheral neuropathy, macular degeneration, osteoarthritis, and heart failure with reduced ejection fraction presents to the clinic for follow-up of her DM and insulin adjustments. Recent laboratory findings include an A1c level of 7.6% (American Diabetes Association goal, lower than 7.5% in older patients); all others are within normal range. Current medications include insulin glargine, 40 units QHS; lisinopril, 20 mg/d; carvedilol, 25 mg twice daily; spironolactone, 25 mg/d; furosemide, 40 mg/d; aspirin, 81 mg/d; gabapentin, 600 mg 3 times daily; and atorvastatin, 20 mg/d. The patient’s home blood glucose log reveals several episodes of either hypoglycemia (home blood glucose level lower than 70 mg/dL) or hyperglycemia (home blood glucose level higher than 250 mg/dL). Her daughter states that the patient has had increasing difficulty self-administering insulin and occasionally has skipped doses.
DM affects almost 30 million persons older than age 20 years, or about 12% of the population.1 In addition to a large percentage of the overall population, DM affects a large number of older patients: Among adults aged 65 years or older, more than 11 million (almost 26% of the older population) have DM.1,2 The number almost certainly will rise as the percentage of the population older than 65 years continues to rise.
Treatment of patients with DM can be difficult, often requiring a multidrug regimen that may contain insulin to attain and maintain glycemic control. Clinicians’ treatment decisions may be influenced by various comorbidities, such as kidney disease, and other factors, such as age.
The American Diabetes Association (ADA) recommends insulin as a second or third add-on agent to metformin in uncontrolled patients or as initial therapy in patients with significant hyperglycemia.3 In a national survey, 14% of adults with DM used insulin alone and almost 15% used insulin in combination with an oral medication1; the rate may be even higher in the older population. Insulin use can present unique problems for safe and effective treatment of these patients because it requires that they have good visual and motor skills and cognitive function.
Although many patients of all ages are treated with insulin therapy, specific concerns arise in the older population regarding the safety and efficacy of this high-alert medication. Insulin therapy can be complicated by multiple comorbidities—such as dementia, neuropathies, poor mobility and dexterity, and vision loss—because these factors can affect the patient’s ability to self-administer the insulin. In addition, safety becomes especially concerning because hypoglycemia can be particularly troublesome in the older population.
The above factors also can affect identification and management of hypoglycemia. Many older patients may make significant errors in drawing up and administering the correct dose of insulin, further contributing to safety and efficacy concerns. As a result, insulin dosing and regimens should be simplified in the older population to maintain efficacy while ensuring safety.4
Insulin therapy in older patients with type 2 DM often can be initiated with basal insulin alone or in combination with oral therapies. Options include intermediate-acting neutral protamine Hagedorn and long-acting glargine or detemir. Although the latter 2 analogues (glargine and detemir) are more expensive, they are associated with lower rates of hypoglycemia, making them better options in older patients.3
As noted above, insulin administration in the older population is associated with a greater possibility of dosing errors.5 Not only is insulin administration complex, but visual and physical disabilities in older patients (eg, visual impairment, joint immobility, and peripheral neuropathy) contribute to inaccurate dosing. Studies have demonstrated that patients who use the traditional vial and syringe method of insulin delivery experience a relative error rate of about 19% with regard to accuracy of dosing6; this rate can be even higher in the older population.
Insulin pen devices, such as the SoloStar (glargine) and the FlexPen (detemir), can help improve the safety and efficacy of insulin administration, and they offer unique advantages for the older population. Large digits and single-unit dosing increments inside the dose window and the use of audible clicking are advantageous for patients who have visual impairment. The larger device size, easy-to-push dose release button, and large dose selector can assist patients who have joint immobility, neuropathy, and other dexterity problems.4
These features can make the pen devices easier to use and preferable, especially among older patients. Studies have shown that use of the insulin pens can significantly improve rates of hypoglycemia and improve dosing accuracy.4,7-9 Although it may take longer to teach older patients to use these devices, patients prefer pen devices and identify them as easier to use than the vial/syringe method.10 Older patients are more likely to self-administer their insulin doses, reducing the burden on caregivers and potentially decreasing costs associated with daily nursing assistance.11 Insulin pens also have been noted to improve adherence rates with injections and to make significant improvements in glycemic control.9
In the case above, the older patient’s insulin therapy may be complicated by polypharmacy and multiple comorbidities, such as neuropathy and arthritis limiting dexterity and age-related macular degeneration leading to visual impairments. These factors may lead to problems drawing up the correct dose using the vial/syringe method as well as difficulty with self-administration. Those problems may lead to an increased risk of hypoglycemia, decreased adherence and resulting hyperglycemia, or both, as this patient is experiencing. Switching to an insulin pen device may help the patient draw up the correct dose by making the dose easier to see and improve administration with easier use.
In addition to the choice of insulin and the use of pen devices, proper patient education is imperative in the older population to ensure that all insulin is administered appropriately and adverse effects are avoided or managed. An interprofessional effort that involves physicians, DM educators, dieticians, nurses, and pharmacists can help provide patients with information regarding all aspects of insulin use, including dosing, injection technique, storage, glucose monitoring, diet, and hypoglycemia recognition and management.
Insulin therapy in older patients can be difficult to manage. The risks of this high-alert medication include hypoglycemia, and therapy often is complicated by multiple comorbidities, polypharmacy, vision impairment, poor mobility and dexterity, neuropathies, and cognitive impairment.
Clinicians must ensure that the most appropriate insulin is chosen and that the method of delivery is safe and efficacious, improving patient ease of use, adherence, and acceptability while decreasing the risk of hypoglycemia. Insulin pens offer greater simplicity, flexibility, and convenience than traditional vial and syringe administration, and features such as audible clicks and large dosing windows help patients who have visual impairments; the greater size and overall ease of use can help patients who have impairments of dexterity. In addition, the interprofessional team should counsel patients on hypoglycemia recognition and management as well how to properly store, dose, and administer insulin.
1. National Diabetes Statistics Report, 2014. CDC. http://www.cdc.gov/diabetes/pubs/statsreport14/national-diabetes-report-web.pdf. Accessed July 14, 2014.
2. Standards of medical care in diabetes—2014. Diabetes Care. 2014;37(Suppl 1):S14-S80.
3. Inzucchi SE, Bergenstal RM, Buse JB, et al. Management of hyperglycemia in type 2 diabetes: a patient-centered approach: position statement of the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). [Erratum in: Diabetes Care. 2013;36:490.] Diabetes Care. 2012;35:1364-1379.
4. Wright BM, Bellone JM, McCoy EK. A review of insulin pen devices and use in the elderly diabetic population. Clinical Medicine insights: Endocrinology and Diabetes. 2010;3:53-63.
5. Coscelli C, Lostia S, Lunetta M, et al. Safety, efficacy, acceptability of a pre-filled insulin pen in diabetes patients over 60 years old. Diabetes Res Clin Pract. 1995;28:173-177.
6. Kesson CM, Bailie GR. Do patients with diabetes inject inaccurate doses of insulin? Diabetes Care. 1981;4:333.
7. Albano S; for the ORBITER Study Group. Assessment of quality of treatment in insulin-treated patients with diabetes using a pre-filled insulin pen. Acta Biomed. 2004;75:34-39.
8. Lee WC, Balu S, Cobden D, et al. Medication adherence and the associated health economic impact among patients with type 2 diabetes mellitus converting to insulin therapy: an analysis of third-party managed care claims data. Clin Ther. 2006;28:1712-1725.
9. Miao R, Wei W, Lin J, et al. Does device make any difference? A real-world retrospective study of insulin treatment among elderly patients with type 2 diabetes. J Diabetes Sci Technol. 2014;8:150-158.
10. Korytkowski M, Bell D, Jacobsen C, Suwannasari R; for the FlexPen Study Team. A multicenter, randomized, open-label, comparative, two-period crossover trial of preference, efficacy, and safety profiles of a prefilled, disposable pen and conventional vial/syringe for insulin injection in patients with type 1 or type 2 diabetes mellitus. Clin Ther. 2003;25:2836-2848.
11. Shelmet J, Schwartz S, Cappleman J, et al; for the Innolet Study Group. Preference and resource utilization in elderly patients: Innolet versus vial/syringe. Diabetes Res Clin Pract. 2004;63:27-35.