In elderly patients, as in all patients, diabetes is much more than the blood glucose level. However, in elderly patients the disease accelerates other common conditions of that population and markedly complicates their management.
Hypertension, coronary artery disease, and cerebrovascular attacks are more common in patients with diabetes.1 Longitudinal studies of elderly and middle-aged people with diabetes show increased rates of cognitive decline and dementia.2–4 Depression, urinary incontinence, and falls are also more common in elderly patients with diabetes. Physical disability is also increased: women with diabetes are half as likely to be able to manage ordinary physical tasks such as walking, climbing stairs, and doing housework as women without diabetes.5
In an earlier paper in this journal,6 we reviewed the management of diabetes per se in elderly patients. In the pages that follow, we review the management of its associated conditions.
HEART RISK TRUMPS BLOOD SUGAR
Coronary artery disease is by far the leading cause of death in elderly people with diabetes: 40% to 50% of patients with type 2 diabetes die of cardiac disease.7–9 The conventional risk factors—hypertension, hyperlipidemia, smoking, and diabetes—remain risk factors throughout old age. Risk reduction should focus on treating hypertension and dyslipidemia, smoking cessation, aspirin therapy, and exercise. While glycemic control reduces the risk of microvascular complications (eg, diabetic retinopathy and nephropathy) after about 8 years of treatment, benefits from control of elevated blood pressure and cholesterol occur after only 2 to 3 years.
Tight control of hypertension confers significant benefit
The United Kingdom Prospective Diabetes Study (UKPDS)10 found that patients who had tight control of blood pressure (mean treated blood pressure 144/82 mm Hg) had 24% fewer diabetes-related end points, 32% fewer diabetes-related deaths, 44% fewer strokes, a 34% reduced risk of deterioration of retinopathy, and a 47% reduced risk of visual deterioration than patients who had usual control (mean treated blood pressure 157/87 mm Hg). The benefit of treating hypertension outweighed the benefits of tight glycemic control.
A strong focus on blood pressure control should be a major focus of any treatment program. The American Geriatrics Society goal for blood pressure is less than 140/80 mm Hg if tolerated. Others have proposed more stringent targets.
Lipid control is integral to managing elderly patients with diabetes. In the Cholesterol and Recurrent Events trial11 and the Heart Protection Study,12 the cardiovascular benefits of reducing serum low-density lipoprotein cholesterol (LDL-C) levels were similar in elderly and younger patients with diabetes. In a meta-analysis of secondary prevention trials, absolute risk reduction was greatest in subjects older than 65 years with either diabetes or diastolic hypertension.
The American Diabetes Association,13 the American Geriatrics Society,14 and the Department of Veterans Affairs15,16 have all set a goal for serum LDL-C of less than 100 mg/dL. In addition, the American Diabetes Association has set goal levels for triglycerides (< 150 mg/dL) and high-density lipoprotein cholesterol (> 40 mg/dL).
The importance of tight glycemic control in preventing coronary heart disease in the elderly is somewhat controversial. Treatment guidelines for elderly patients with diabetes are mainly extrapolated from the UKPDS, in which patients were a mean of 54 years old at the start of the study. After 10 years, the mean hemoglobin A1c levels were 7.9% in patients receiving conventional control and 7.0% in patients with intensive therapy. Every 1% reduction in hemoglobin A1c was associated with a 37% decline in microvascular complications of diabetes, a 14% decline in myocardial infarctions, and a 21% decline in any diabetes-related outcome.17
In the original trial,18 the rate of myocardial infarction was 17.4% in the conventional treatment group vs 14.7% in the intensive group (P = .052), and the risk of stroke did not differ. No thresholds for realizing benefits from reducing fasting glucose or hemoglobin A1c levels were detected.
A recent cohort study involving about 10,000 participants aged 45 to 79 years found that the risk of cardiovascular disease and death from any cause increased continuously with increasing hemoglobin A1c levels in people with or without diabetes.19 However, the impact of treatment remains to be clarified. The Action to Control Cardiovascular Risk in Diabetes trial will address this question (and others), but results will not be available for several years.