Intensive BP and cholesterol treatment didn't affect cognitive decline after 40 months

In patients with type 2 diabetes, intensive control of blood pressure and cholesterol did not protect against cognitive decline, a recent study found.

This substudy of the ACCORD trial included 2,977 patients with type 2 diabetes, a hemoglobin A1c (HbA1c) of at least 7.5%, and no evidence of cognitive impairment or dementia at baseline. About half of the patients (n=1,439) were randomized to a systolic blood pressure goal of either under 120 mm Hg or under 140 mm Hg. The other group (1,538 patients) had LDL cholesterol levels less than 100 mg/dL and were randomized to either a fibrate or placebo. Results were published online Feb. 3 by JAMA Internal Medicine.

Cognition was assessed at baseline, 20 months and 40 months in all patients; a subset of 503 patients also underwent brain magnetic resonance imaging (MRI) at baseline and 40 months. No differences in cognition were found among any of the trial groups. Among the patients who had brain MRIs, total brain volume by 40 months declined more in the intensive blood pressure control group than the standard care group (difference, −4.4 cm³; 95% CI, −7.8 to −1.1; P=0.01).

The study authors concluded that intensive blood pressure and lipid therapy did not measurably affect cognitive decline in the studied patient population. They noted that the studied patients, with a mean HbA1c of 8.3% and disease duration of 10 years, had relatively longstanding and poorly controlled disease. The findings extend the previous observation of the ACCORD MIND trial that intensive glucose control did not preserve cognitive function in similar patients.

Intensive glucose control did, however, maintain total brain volume more than standard care in that trial, the opposite of this study's finding with blood pressure control. These results suggest that total brain volume cannot be used as a surrogate marker for cognitive outcomes, the researchers said. They also noted that cognitive decline is a slow process and that longer-term data (currently being gathered in an extension of this study) could reveal more subtle differences between the groups. Overall, though, the results “make clear the decreasing returns of intensive medication-based therapy for advanced [type 2 diabetes],” the authors concluded.

According to an invited commentary, the study provides reason for exploring other treatments for preventing the cognitive decline associated with diabetes and a reminder that “enthusiastic control of [blood pressure] later in life should be pursued with caution and based on existing evidence, not extrapolated benefits.”