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.
Intensive blood pressure and cholesterol lowering was not associated with a reduced risk of cognitive decline in older patients (mean age 62 years) with longstanding type 2 diabetes mellitus, a study has found.
Patients with type 2 diabetes are at increased risk of decline in cognitive function, reduced brain volume, and increased white matter lesions on brain imaging, says background information given in the paper.1
Preliminary studies have indicated that intensive treatment to control blood pressure and lipid concentrations may prevent some of this cognitive decline, and the authors set out to test this hypothesis.
Altogether 2977 participants without cognitive impairment or dementia and with haemoglobin A1C concentrations less than 7.5% were enrolled into the study. A total of 1439 patients entered the blood pressure arm and were randomly assigned to intensive intervention to achieve a systolic blood pressure of less than 120 mm Hg or standard intervention to reach a goal of less than 140 mm Hg.
All the 1538 patients in the lipid arm of the trial were taking a statin, and they were randomised to receive a fibrate or placebo.
Researchers assessed cognition in patients at baseline and again at 20 months and 40 months. In addition, 503 participants underwent baseline and 40-month magnetic resonance imaging to look for changes in total brain volume and other structural measures of brain health.
The study, published in JAMA Internal Medicine, showed that there were no differences in cognitive function between patients who received intensive treatment to lower blood pressure (<120 target) or standard treatment and those treated with a fibrate or placebo.
Researchers also found that at 40 months patients in the intensive blood pressure intervention group had a lower total brain volume than did the patients in the standard blood pressure intervention group (difference −4.4 cm3 (95% confidence interval −7.8 to −1.1); P=0.01). Fibrate therapy had no effect on brain volume.
The authors concluded, “During the past two decades, the belief that more intensive treatment strategies for controlling T2DM [type 2 diabetes mellitus]-related comorbidities, such as hyperglycemia, hyperlipidemia and hypertension, would reduce clinical complications has driven large investment in new medications for this disease syndrome.
“These results do not negate other evidence that intensive strategies to control BP [blood pressure] and lipid levels may be indicated for other conditions such as stroke or coronary heart disease. However, 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.”
The study was funded by the US National Institute on Aging and the National Heart, Lung and Blood Institute of the US National Institutes of Health.
- Williamson JD, Launer LJ, Bryan RN, Coker LH, Lazar RM, Gerstein HC, 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 Intern Med 4 Feb 2014 [PubMed® abstract of JAMA Intern Med article]