Centrally acting ACE inhibitors (CACE-Is) may slow cognitive decline in patients with dementia, a team of researchers from Ireland and Canada found. The standardized test scores of patients who took CACE-Is decreased more slowly than patients who did not, and they improved in patients who just started treatment within the past six months.

In an observational case-control study, the authors, led by Yang Gao, MSc, of University College Cork in Cork City, Ireland, administered the Standardized Mini-Mental State Examination (SMMSE) and the Quick Mild Cognitive Impairment (Qmci) tests to patients with either Alzheimer’s dementia, vascular or mixed dementia from two memory clinics.

They compared the test scores between those patients taking CACE-Is, those not taking CACE-Is (NoCACE-Is) and those who started the drugs within the past six months (NewCACE-Is).

Of the 817 patients with dementia, 361 with SMMSE and Qmci scores from two or more visits were included in the study analysis. Eighty-five of the 361 were under treatment with CACE-Is and 235 were not.

The patients taking CACE-Is had a significantly slower rate of decline over the first six months. Qmci scores decreased by 1.8 points compared with 2.1 points for the NoCACE-Is. The trend was similar, but not significant, with SMMSE results.

Average SMMSE scores improved by 1.2 points during the first six months for the NewCACE-Is, while there was a decrease of 0.8 points among the CACE-Is and a 1 point decline in the NoCACE-I group.

“This is the first study to demonstrate that cognitive scores improve in patients starting on CACE-Is, compared to those already established on maintenance treatment,” the authors wrote. “This may have been related to better medication compliance, the effects of improved BP [blood pressure] control or increased cerebrovascular perfusion after initial treatment.”

Results from other studies have also suggested that using ACE-Is and other antihypertensives may help with dementia management, but research has also found that ACE-Is could increase the amount of amyloid plaques and hasten dementia. ACE-Is also may cause an increase in mortality, so more research is needed to better sort out the role of ACE inhibitors.

“If these data can be reproduced in a randomized trial of sufficient length incorporating appropriate outcome measures, such as an amyloid positron emission tomography, then these agents are likely to have significant benefits in delaying or even preventing dementia," the authors concluded.

The study was published online July 22 in BMJ.