Is Low BP Linked to Diabetes-Related Cognition?
A new study finds intensive blood pressure and cholesterol lowering has no connection with a lesser risk for diabetes-related cognitive decline in older patients with type 2 diabetes mellitus.
A group of investigators led by researchers at the Wake Forest School of Medicine studied the effect of intensive treatment to lower blood pressure and lipid levels, as part of the Memory in Diabetes sub-study of the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial.
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The trial randomized 2,977 participants without baseline cognitive impairment or dementia, and with hemoglobin A 1C levels less than 7.5 percent to a systolic BP goal of less than 120 or less than 140 mm Hg (n=1,439), and to a fibrate or placebo in patients with statin-treated, low-density lipoprotein cholesterol levels less than 100 mg/dL (n=1,538).
Researchers assessed cognition at baseline, 20, and 40 months. In addition, 503 participants underwent baseline and 40-month brain magnetic resonance imaging to look for changes in total brain volume (TBV) and other structural measures of brain health. Investigators found no differences in cognitive function in the intensive BP-lowering trial (<120 target) or in the fibrate groups. At 40 months, the intensive BP intervention group had a lower TBV compared with the standard BP intervention group. Fibrate therapy had no effect on TBV.
Study authors conclude the longstanding belief that more intensive treatment strategies for controlling type 2 diabetes mellitus-related co-morbidities such as hyperglycemia, hyperlipidemia, and hypertension would reduce clinical complications has driven large investments in new medications for this disease syndrome. These results do not negate other evidence that intensive strategies to control BP and lipid levels may be indicated for other conditions such as stroke or coronary heart disease, according to the authors.
However, the researchers noted that this randomized clinical trial shows no overall reduction of the rate of T2DM-related cognitive decline through intensive BP therapy or adding a fibrate to well-controlled LDL-C levels.
“Recently issued national guidelines recommend keeping systolic blood pressure under 140 mm Hg and using statins in most patients with type 2 diabetes, as was done in the standard blood pressure and lipid treatment groups in ACCORD,” adds Karen Margolis, MD, MPH, senior investigator at HealthPartners Institute for Education and Research, a professor of medicine at the University of Minnesota Medical School, and a co-author of the study.
As such, “I would say the message for primary care practitioners is that this study provides evidence that current national guidelines for managing blood pressure and lipids in patients with type 2 diabetes are also appropriate for preserving cognitive function,” says Margolis.
—Mark McGraw
Reference
Williamson J, Launer L, et al. Cognitive Function and Brain Structure in Persons With Type 2 Diabetes Mellitus After Intensive Lowering of Blood Pressure and Lipid Levels: A Randomized Clinical Trial. JAMA Internal Medicine. 2014.