The Elderly and Insulin Therapy
It is projected that by the year 2025 the majority of patients with diabetes will be aged 65 or older. Diabetes prevalence will increase by more than 200% in persons aged 65-74 and by more than 400% in those 75 and older. In patients with diabetes, the disease itself already accounts for 52% of nursing home admissions and 47% of deaths – percentages that only increase when corrected for related cardiovascular conditions.
The Merck Manual of Geriatrics recommends a glycemic goal of A1C < 7% for all elderly patients and states that most elderly patients can be treated as aggressively as younger patients.
The majority of patients who are elderly will eventually require insulin due to loss of beta cell function in the pancreas. At diagnosis, for example, many patients have already lost 50% of their beta cell function and six years post-diagnosis shows another 25% loss.
Furthermore, there are some contraindications in the elderly to using the more traditional drugs such as metformin and oral sulfonylurea agents. With metformin, the manufacturer recommends that “treatment should not be initiated in patients > 80 years of age unless calculated creatinine clearance demonstrates that renal function is not reduced”. In addition to the above contraindications, gastrointestinal side-effects such as anorexia, nausea and abdominal discomfort are observed in up to 30% of patients on these drugs.
Oral sulfonylurea agents can cause hypoglycemia which may precipitate other adverse events such as falls. Chlorpropamide should not be used in the elderly owing to its long half life, antidiuretic effect and association with severe and prolonged hypoglycemia. Patients with renal, cardiac, or liver problems should not take the older sulfonylureas (i.e. glyburide). If sulfonylureas are used, the preferred ones are the shorter-acting drugs.
Patients with liver enzymes >50% the upper limit of normal should not be prescribed thiazolidinediones, nor should those with moderately severe CHF. Fluid retention and leg edema may also be limiting side-effects of these drugs.
Insulin is the most powerful agent we have for lowering blood glucose and updated treatment guidelines recommend initiation of therapy earlier in the disease process, contradicting the long held treatment paradigm of insulin as “last line” therapy. Physiologic insulin replacement using the newer insulin analogs can improve glycemic control with a lower risk of hypoglycemia and should be considered a more routine component of diabetes treatment. They are also more cost-effective for the older person. Insulin therapy is now being recommended as the appropriate treatment choice for many older patients.
Reference: The Consultant Pharmacist. Special Needs and Opportunities for Educating the Elderly on Diabetes and Insulin. Supplement B, April, 2008, Vol 23.
About the Author
Kathy Shattler received her Master of Science degree from Michigan State University in E. Lansing Michigan in Human Nutrition. Her twenty-two years of practice includes holding positions as a Lecturer, Chief Clinical Dietitian and Program Manager. Kathy is the Founder of Nutri-Care Consulting and is currently the Nutrition Director of www.CEU4U.COM, an online continuing education management company for Registered Dietitians and Dietetic Technicians.
