Diabetes in the Older Adult: Recommendations for Glycemic Control

 

US Pharm.  2014;39(10)(Diabetes suppl):6-10.

ABSTRACT: Older adults with diabetes more often have comorbidities, experience one or more geriatric syndromes, and may be more sensitive to the hypoglycemic effects of antidiabetic medications; therefore, their management needs differ from those of younger patients. The goals of diabetes management in the older adult are to prevent hypoglycemia and to minimize diabetes-related complications, particularly microvascular consequences. A number of professional organizations have published recommendations for target blood-glucose levels in older adults with type 2 diabetes. These recommendations take into consideration the presence of comorbidities and the risk of hypoglycemia in this population.

Older adults with diabetes constitute a heterogeneous group with varying degrees of functional and cognitive impairment. The needs of older diabetic adults differ from those of younger patients since this population more often has comorbidities, experiences one or more geriatric syndromes, and may be more sensitive to the hypoglycemic effects of antidiabetic medications. The goals of diabetes management in the older adult is to prevent hypoglycemia and to minimize diabetes-related complications, especially microvascular consequences. Recently, several professional organizations disseminated clinical-practice guidelines or position/consensus statements on the management of diabetes in the older adult. This article compares target goals and strategies for glycemic control in these new recommendations.

The Scope of Diabetes in Older Adults

Diabetes mellitus (DM) is extremely common in the elderly and is the seventh leading cause of death in the United States.¹ Older adults have the highest prevalence of DM compared with other populations.² The CDC’s National Diabetes Statistics Report for 2014 estimates that 29.1 million Americans, or 9.3% of the U.S. population, have DM; this figure includes 8.1 million undiagnosed cases. DM afflicts 11.2 million older adults, or 25.9% of those aged ≥65 years. In 2012, there were 400,000 new cases of diabetes among persons aged ≥65 years, signifying a rate of 11.5 new cases per 1,000 persons (vs. 7.8 per 1,000 among the overall population aged ≥20 years). Among ethnic groups including Hispanics, non-Hispanic blacks, and American Indians/Alaska Natives, age-adjusted percentages of adults with DM were higher than for the overall population.¹ Further, 51% of persons aged ≥65 years have prediabetes, compared with 37% of the overall adult U.S. population.¹

Prediabetes is defined as a glycosylated hemoglobin (HbA_1c) of 5.7% to 6.4%; a fasting plasma glucose of 100 to 125 mg/dL; or a 2-hour blood glucose of 140 to 199 mg/dL on an oral glucose tolerance test.³ Without lifestyle changes, 15% to 30% of people with prediabetes will develop type 2 diabetes (T2DM) within 5 years.⁴ These numbers, which are already staggering, are set to increase as more baby boomers reach 65 years of age and the U.S. population becomes more ethnically diverse. T2DM accounts for 90% to 95% of diabetes cases in adults.¹ Among older adults living in nursing facilities, 24.2% have DM.⁵ See TABLE 1 for a summary of diagnostic criteria for DM.

DM in older adults is associated with multiple comorbidities and geriatric syndromes (e.g., cognitive dysfunction, functional impairment, falls and fractures, polypharmacy, depression, vision and hearing impairment, pain, urinary incontinence). These comorbidities and syndromes complicate drug regimens, produce greater functional impairment, increase rates of institutionalization, and are associated with higher mortality rates.² Increased insulin resistance and impaired pancreatic islet cell function are the major reasons for the age-related increase in DM.² Cardiovascular disease is the main contributor to death in this population. This group has the highest rates of myocardial infarction, major lower-limb amputation, visual impairment, and end-stage renal disease.²

Practice Guidelines and Position/Consensus Statement Recommendations on T2DM Management

Several clinical-practice guidelines and position/consensus statements have been published that address the management of T2DM in older adults.^2-13 However, few controlled trials have examined glycemic control in older diabetic patients, and many of the recommendations in these guidelines are extrapolated from younger populations.²

In 2012, the American Geriatrics Society published a consensus report on DM in older adults; in 2013, it disseminated guidelines for improving the care of these patients.^2,6 The International Diabetes Federation has published global guidelines on the management of older people with T2DM. These guidelines focus on the management of T2DM in patients aged ≥70 years and categorize patients according to functional independence, functional dependence plus frailty or dementia, and nearness of end of life. Up to 25% of older adults with DM are frail; these patients experience significant fatigue, weight loss, and severely restricted mobility and strength and are at increased risk for falls and institutionalization, all of which can impact the patient’s ability to perform DM self-management. For patients with dementia, who may be unable to recognize symptoms of hypoglycemia or hyperglycemia and may have problems adhering to a drug regimen, the focus is on patient safety rather than rigid glycemic goals.⁷ The International Association of Gerontology and Geriatrics, the European Diabetes Working Party for Older People, and the International Task Force of Experts in Diabetes have developed a position statement addressing key issues in the management of DM in older adults and specifying areas in need of further research.¹²

The recommendations also address the management of hypertension and hyperlipidemia, which are major causes of cardiovascular death and disability in this population, but these topics are beyond the scope of this paper. Control of hypertension and hyperlipidemia in older adults with T2DM has a greater effect on reducing morbidity and mortality than tight glycemic control, as it can take up to 20 years to demonstrate a significant decrease in coronary artery disease outcomes from more stringent glycemic management.⁷

Recommendations on Glycemic Control

The goals of glycemic control in the older adult are to minimize symptoms related to hyperglycemia (e.g., tiredness, thirst, polyuria, dehydration, ketoacidosis, hyperosmolar state, delirium, cognitive impairment, depression); reduce cardiovascular risk (if possible) and microvascular disease; encourage self-care; and reduce fall risk without exposing the patient to episodes of hypoglycemia. Target blood-glucose goals (TABLE 2) should take into consideration factors such as comorbidities, established cardiovascular disease, history of hypoglycemia, occurrence of vascular complications, age, diabetes duration, concomitant medications, functional status, frailty, dependency, physiological function, cognitive status, life expectancy, socioeconomic status, attitude and expected treatment efforts, and family and/or community resources.^{7,8,11,12,14,15}

The key to managing T2DM in the older adult is individualization of therapy (also known as the patient-centered approach). Lifestyle modifications should be initiated first. Intensive glucose control (i.e., HbA_1c <6.5%) is generally not recommended in elderly patients, as it has been associated with harm (i.e., increase in all-cause and cardiovascular mortality, severe hypoglycemia, weight gain).^6,16 More intensive glycemic control may be suitable for younger adults who are expected to live long enough to reap the microvascular benefits of a more restrictive regimen, or for newly diagnosed older patients who may benefit from reductions in both microvascular and macrovascular complications. However, in elderly patients with multiple comorbidities and a limited life expectancy (<5 years), intensive control subjects the patient to hypoglycemia while affording little immediate vascular protection.¹⁷ The frequency of glucose self-monitoring is dependent on the intensity of therapy, functional and cognitive abilities, the patient’s quality of life, and the risk of hypoglycemia.⁶

Older adults have more comorbidities and complications secondary to DM (e.g., nephropathy, retinopathy, neuropathy, macrovascular disease), which make management difficult. Further, there are age-related changes in body composition and organ function that may affect the pharmacokinetics and pharmacodynamics of medications and may predispose older adults to more adverse drug effects. Recommendations for the use of hypoglycemic agents in older adults with T2DM are found in TABLE 3.

Hypoglycemia

Hypoglycemia has been associated with adverse outcomes in older adults, which can have devastating consequences such as worsening cognition, decreased quality of life, falls, and death.^18,19 More restrictive blood-glucose goals are associated with a greater risk of hypoglycemia. Aging is associated with hypoglycemic unawareness, which renders elderly patients less able to recognize symptoms of hypoglycemia.⁶

CDC statistics highlight the problem facing diabetes care in this country. In 2011, among U.S. adults, there were approximately 282,000 emergency-room visits in which the primary diagnosis was hypoglycemia.¹ The draft version of the National Action Plan for Adverse Drug Event Prevention (released in 2013) targets insulin- and oral agent–induced hypoglycemia as a priority, since hypoglycemic agents are one of the drug classes most frequently associated with adverse drug events in both the inpatient and outpatient setting and rank as the third most common cause of adverse drug events among hospitalized Medicare patients. The purpose of the National Action Plan is to identify common, clinically significant, preventable, and measurable adverse drug events and to align the efforts of federal health agencies to reduce patient harm.²⁰

The FDA is considering how hypoglycemia can be used as an endpoint in clinical trials.¹⁹ Metformin, thiazolidinediones, alpha-glucosidase inhibitors, dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists, and sodium-glucose cotransporter 2 inhibitors have a low potential for causing hypoglycemia, and their use may be preferred in the elderly, provided that there are no contraindications to their administration.^11,21

Conclusion

The management of DM and its associated comorbidities is complex in the older adult, resulting in complicated drug regimens, problems with nonadherence, and the increased potential for adverse drug events and drug-drug interactions. The presence of geriatric syndromes further complicates the implementation of a therapeutic plan of care. The pharmacist can play an active role in the medication therapy management of DM and its related complications in this population by providing the highest level of pharmaceutical care. This involves the development of individualized treatment plans that take into account the patient’s goals and preferences, as well as patient-specific factors that can impact drug therapy. Using patient-education strategies, the pharmacist can help ensure that his or her older adult patients have a thorough understanding of their disease state and its management, which will help achieve positive therapeutic outcomes.

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