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Benefits of Insulin Pump Therapy in the Elderly
by Ali A. Rizvi, M.D.
Geriatric Times May/June 2002 Vol. III Issue 3
Diabetes is a growing health problem that has assumed almost epidemic proportions in our society (Boyle et al., 2001). A significant number of elderly people with diabetes have type 1 diabetes that was diagnosed in childhood or young adulthood. These patients are often suboptimally controlled with insulin injections, leading to microvascular complications of neuropathy, retinopathy and nephropathy, as well as macrovascular disease. The other, larger elderly group has type 2 diabetes, which increases in incidence with age, physical inactivity and weight gain (Franse et al., 2001). These factors are known to increase insulin resistance and impair ß-cell function, thus contributing to progression of this disease.
Treatment methods for diabetes in the elderly include lifestyle changes, dietary manipulation, weight management, oral agents and insulin, which is commonly given in the form of one or more daily injections. It is often difficult to mimic physiologic insulin delivery and dovetail insulin action to blood glucose. The result is suboptimal metabolic control and unpredictable glycemic excursions, even when a complex insulin regimen with multiple injections is employed. Lifestyle restrictions and curtailment of flexibility are additional drawbacks that may decrease treatment satisfaction.
Advantages of the Insulin Pump
Continuous subcutaneous insulin infusion by insulin pump has gained increasing acceptance in recent years as an effective mode of insulin delivery (Marcus and Fernandez, 1996). The pump continuously delivers short-acting insulin at a predetermined basal rate, which is pre-programmed according to the individual's 24-hour glycemic profile. In order to provide coverage for post-prandial elevations, bolus insulin is administered based on premeal glucose values and the amount of carbohydrate being ingested.
The greatest factor in convincing the increasing number of physicians and patients who embrace pump therapy has been its proven ability to improve glycemic control, reduce the frequency of hypoglycemic episodes and improve quality of life by allowing for more scheduling flexibility and variability (Bell and Ovalle, 2000; Bode et al., 1996; Home et al., 1982). Pump therapy is thus traditionally prescribed for young, motivated patients (Boland et al., 1999; Brink and Stewart, 1986) and for the treatment of diabetes during pregnancy (Gabbe et al., 2000).
Insulin Pump Use in the Elderly
Farkas-Hirsch and Hirsch (1994) have pointed out generalizations and misconceptions about this treatment in elderly patients with diabetes, who may be seen as unable to retain new information and slow to react in emergency situations. Perceived barriers -- like learning to use pump features and carbohydrate counting and safety considerations -- may cause caregivers to be hesitant to entrust older people with insulin pumps. Other reasons include the magnitude of effort required, presence of diabetic complications, perceived lack of patient motivation and cost. Change from a previously familiar routine also can cause apprehension in many individuals. All these factors may contribute to the image of older patients being less than ideal candidates for pump therapy.
Potential Benefits for the Elderly
Recent data suggest that the aforementioned concerns may not be justified. A small but growing body of experience suggests that carefully selected elderly patients can benefit enormously from the advantages offered by the insulin pump. Case studies and anecdotal reports have been published demonstrating the feasibility of insulin pump use in patients in their seventh and eighth decades of life (Davidson, 1995; Farkas-Hirsch and Hirsch, 1994; Mecklenburg et al., 1982). Kamoi (2002) recently described good long-term quality of life in a brittle 72-year-old diabetic woman treated for 20 years with continuous subcutaneous insulin therapy who remained free of complications by maintaining excellent glycemic stability.
Our group has previously reported success in a small number of older subjects when switched from injections to pump therapy (Rizvi et al., 2001). They had long-standing type 1 diabetes with suboptimal glycemic control and presence of complications. Glycosylated hemoglobin was significantly better on the pump after more than a year of follow-up. Concurrent with improved metabolic control, there was a reduction in insulin requirements and decreased propensity to hypoglycemia in our study patients. In other words, pump therapy offered a more physiologic and effective use of available insulin.
Since the publication of our initial report in 2001, we have accumulated favorable experience with pump use in older patients with type 2 diabetes, especially those requiring large amounts of injected insulin (signifying underlying insulin resistance). These patients have been able to achieve better glucose control and reduce insulin dosages. Recent reports of the benefits of pump therapy in the type 2 population have included older individuals (Lenhard and Maser, 2001; Testa et al., 2001), and such use is likely to increase in the future.
What is the basis for these observations? Studies have proven that the pharmacokinetic approach of continuous basal-bolus insulin can decrease glycosylated hemoglobin values beyond that seen with maximal use of injections (Bell and Ovalle, 2000; Hanaire-Broutin et al., 2000). Calculated premeal boosts of short-acting insulin mimicking normal pancreatic action are able to effectively control post-prandial glycemic excursions. Pump therapy has also been demonstrated to be very valuable in treating the dawn phenomenon, which is often extremely difficult to manage with injections (Koivisto et al., 1986). The overnight basal insulin rate can be precisely programmed and tailored to attenuate the early morning and pre-breakfast glucose elevations. As demonstrated by the Diabetes Control and Complications Trial (DCCT) Research Group (1993), improved glycemic control retards the progression of undesirable chronic sequelae of diabetes. Avoidance of outcomes such as renal failure, blindness and amputations would improve quality of life and be cost-effective as well.
Reproducible insulin delivery afforded by pump use also decreases variability in blood glucose levels (Lauritzen et al., 1983), thus translating into reduced risk of hypoglycemic events. Recurrent iatrogenic hypoglycemia can blunt hormone counterregulation and induce hypoglycemic awareness over time (Cryer, 1994; Gold et al., 1994). This is a significant cause of psychosocial and physical morbidity and mortality in insulin-treated diabetes. Besides creating great psychological distress (Wredling et al., 1992), it perpetuates a vicious cycle of fear and anxiety (Irvine et al., 1992). Pump therapy can reduce frequent, debilitating hypoglycemic episodes and lead to freedom from bothersome and frustrating symptoms in daily life (Hirsch et al., 1991). Its immense psychosocial impact and lifestyle benefit make it a goal worth pursuing in the elderly diabetic population. In practical terms, it has beneficial effects regarding level of treatment satisfaction, morale and quality of life. It is also likely to reduce health care burden and costs by avoiding emergency department visits and hospitalizations. Finally, the pump provides lifestyle flexibility with regard to timing and amount of meals, snacks and physical activity, which is another distinct advantage. Indications for using insulin pumps in the elderly are shown in Table 1.
Implementing Pump Therapy
Patients are recommended for pump therapy when insulin injections are inadequate in achieving treatment goals. Patients may display suboptimal metabolic control (glycosylated hemoglobin >8.0%), unacceptably high frequency and severity of hypoglycemic reactions, and a general sense of treatment dissatisfaction. Lack of lifestyle flexibility and spontaneity is also an important indication. The goals of pump use, therefore, should be tailored to the individual needs of the patient. The cost-benefit ratio in a particular individual should be taken into account. Factors influencing this decision include, but are not limited to, general health, life expectancy, comorbid conditions, cognitive abilities and the presence of advanced diabetes complications.
There are several key requirements for successfully initiating pump therapy in the elderly. The availability of a professional multidisciplinary diabetes care team with skill and experience in this area is critically important (American Association of Diabetes Educators [AADE], 1997; American Diabetes Association [ADA], 2002). The team educates the patient in the preparative phase and provides round-the-clock contact to troubleshoot problems in the early phases of insulin pump initiation. Long-term support and guidance is necessary to address questions and provide prompt solutions to unique daily situations (Lavin-Tompkins, 1997). As in the other age groups with diabetes, proper selection of older candidates for pump therapy is vitally important: patients should have intact cognitive skills and maintain a thorough understanding of the basics of pump therapy, its risks and benefits, and the effort required to successfully make the transition. They should be familiar with various aspects of self-care and maintain close contact with members of the diabetes team. Management capabilities like dietary compliance and intensive self-monitoring should be thoroughly assessed.
All patients should receive instruction in diabetes self-management skills and optimal nutrition prior to initiating insulin pump treatment. Additionally, they should undergo insulin pump education and sessions in carbohydrate or meal counting. The goals of this intensive period are threefold: to evaluate preliminary skills in diabetes management, to address areas of concern and potential weaknesses, and to assess acquisition of new information. The following points are reinforced: 1) frequent self-monitoring of plasma glucose by finger-stick analysis, 2) proper measures to take in case of high and low glucose readings, and 3) accurate carbohydrate or meal counting and use of supplemental insulin for determining premeal insulin boluses.
Practical aspects, including insulin replenishment, timely replacement of tubing, proper care of needle insertion sites and procedures to follow in case of pump malfunction, need to be emphasized. Vigilance about potential problems during pump therapy, like interruption of insulin delivery and inflammation or infection of the needle insertion site, should be stressed. Most treatment "snags" are not related to the pump but rather to lapses in human judgment. Although the latter are more apt to happen in the elderly, they are probably no more common with pump use than with any other intensive diabetic treatment regimen (combination oral medications or multiple-dose insulin injections). The components of a successful pump therapy program are outlined in Table 2.
In our experience, pump therapy in the elderly is best initiated with a 23-hour observation stay in the hospital. The daily insulin requirement is established at 75% to 80% of the injection dose. Half of this amount is given as continuous basal insulin while the rest is divided into three bolus doses for use prior to meals. Daily outpatient follow-up during the first few weeks of pump use is done by telephone or fax. During this time, patients are seen for office appointments on a weekly basis. Close communication between members of the diabetes management team is maintained to discuss progress of individual patients toward their treatment goals.
A significant number of older patients with diabetes reside in personal care homes or skilled care nursing facilities. This should not be regarded as a contraindication to pump use as long as the patient, a family member and nursing staff demonstrate a level of familiarity and comfort with pump therapy, and close supervision is maintained by an experienced health care professional. In fact, in some situations, the advantages of using the pump may well be worth the extra effort.
An added impetus for the use of pump therapy in the elderly derives from Medicare's decision to cover this mode of treatment as long as certain criteria are satisfied. A recent amendment relaxed the C-peptide requirement and included coverage for type 2 diabetes. Since most people covered by Medicare are older than age 65 with type 2 diabetes, they are expected to be the main beneficiaries of this action. Under the Balanced Budget Act of 1997, Medicare will cover the cost of glucose meter test strips required for frequent self-monitoring in insulin-requiring diabetes as long as the treating clinician certifies that the extra testing is justified (as in an intensive multiple-injection regimen or insulin pump therapy) and a daily record of the patient's home glucose measurements is maintained. Sessions covering education and practical aspects of diabetes self-care are also reimbursed by Medicare as long as they are delivered within an ADA-recognized diabetes program and certain other conditions are met.
Conclusions
Most of the data regarding the various benefits of insulin pump therapy for the treatment of diabetes have been reported in young adults and children. A promising amount of information is now accumulating delineating similar effects in older patients. For optimal results, it is important that patients in this age group be selected carefully, educated thoroughly and followed diligently under the auspices of a team of trained professionals. It is expected that pump application will increase due to factors such as better insurance coverage, affordability, user-friendly gadgetry and increased awareness of treatment options (Bode et al., 2001; Klein et al., 1996). The elderly diabetic population will continue to increase into the 21st century. Although fulfillment of generally accepted criteria for insulin pump therapy remains essential, age should not be considered a barrier in providing older patients with its benefits. Future favorable experience should firmly establish the role of the pump as a viable treatment option for the elderly with insulin-treated diabetes.
Dr. Rizvi is assistant clinical professor of medicine at the Medical College of Georgia. He is active in patient care, teaching and clinical research.References
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