What medications should be considered for the treatment of type 2 diabetes in older adults?
Special care is required in prescribing and monitoring drug therapy for older patients with diabetes. Metformin has traditionally been considered contraindicated when the eGFR is < 60 mL/min; however, recent studies have shown that metformin can be used safely in patients with an eGFR of 30 to 60 mL/min (with a suggested dose reduction by half when the eGFR is 30–45 mL/min). Because serum creatinine levels alone are often not an adequate reflection of the GFR in older patients, it is important to assess the eGFR that also accounts for age and body weight. Metformin is still contraindicated for those with acute illness, hospitalization, severe renal impairment (eGFR < 30 mL/min), and significantly impaired hepatic function because of the potential risk of lactic acidosis.
Thiazolidinedione use in the elderly is generally not recommended for those at increased risk for congestive heart failure (CHF) or fractures (e.g., elderly postmenopausal females). Furthermore, there is a modest cumulative dose-related increased risk of bladder cancer in patients taking pioglitazone. Long-acting insulin secretagogues, especially the sulfonylurea, glyburide, can cause hypoglycemia in the elderly and are contraindicated. Even the shorter-acting insulin secretagogues (glipizide and glimepiride) should be used with caution because elderly adults are particularly predisposed to hypoglycemia, especially those who skip meals.
Glucagon-like peptide-1 (GLP-1)–based therapies act in a glucose-dependent manner and are associated with much less hypoglycemia. The advantages of Dipeptidyl peptidase-4 (DPP-4) inhibitors are that they can be used (with dose adjustments) in those with renal impairment and are orally dosed once daily. There is concern about an increased risk of CHF hospitalizations in patients using certain DPP-4 inhibitors (saxagliptin). Although the DPP-4 inhibitors are considered weight neutral, GLP-1 receptor agonist therapy tends to cause weight loss. Although dosed once daily to once weekly, GLP-1 injections require good visual and motor skills for proper injection technique.
Insulin injections may be problematic for the patient with visual impairment and require that the patient or = caregiver have sufficient ability to follow a prescribed regimen. Overtreatment with or a mistimed dose of insulin can easily cause hypoglycemia. In the elderly, hypoglycemia may be particularly hard to identify, and recurrent hypoglycemic episodes may be incorrectly diagnosed as irreversible cognitive impairment. Management of diabetes with insulin therapy can be improved in elderly patients with visual impairment through the use of assistive devices, such as glucometers with large easier-to-read screens, audio glucometers, magnifying glasses and preloaded insulin pens.
The newest antidiabetes agents are the sodium–glucose cotransporter-2 (SGLT-2) inhibitors. Meta-analyses of studies have shown that these agents can be used safely in elderly patients with beneficial effects of lowering HbA 1C , possible lowering of systolic blood pressure, and reduced body weight. However, SGLT-2 inhibitors have been associated with increased frequency of genital and urinary tract infections and euglycemic ketoacidosis, and thus longer term safety data are needed.