Long-term cholesterol and blood pressure-lowering drugs have failed to show a cognitive benefit in older adults in a sub-study of the HOPE-3 trial but findings suggest there may be some benefit for those at highest cardiovascular risk.
Lowering blood pressure using candesartan plus hydrochlorothiazide or rosuvastatin to lower cholesterol, or a combination of the two, did not slow cognitive decline over a median of 5.7 years, found the study involving 1,626 people with an average age of 74 who had a moderate risk of heart disease – defined as having a 1 percent chance of having a heart attack or event during the year.
However, the authors from the Population Health Research Institute and the School of Rehabilitation Science at McMaster University in Hamilton, Ontario, Canada found that in a subgroup of 181 people at highest cardiovascular risk (BP >145 mm Hg and LDL-C >140 mg / dL), the combination of BP lowering and rosuvastatin compared with placebo reduced cognitive decline on the study’s primary outcome of the Digit Symbol Substitution Test.
“Our results indicating an effect of combined blood pressure and lipid lowering in the prevention of cognitive decline in those with the highest initial blood pressure levels suggest that those at highest cardiovascular risk may benefit,” the authors wrote in their paper published in Neurology.
Their finding that lipid lowering with rosuvastatin, a hydrophilic statin, did not worsen cognitive decline was consistent with the results of recent meta-analyses indicating that statins have no adverse effect on cognitive function.
“It is likely that the results from observational studies that report a harmful effect of statins on cognition are confounded” they wrote.
They added that longer studies were needed as taking medications for six years may not be long enough to prevent cognitive decline.
In an accompanying editorial Christopher Chen from the Memory Ageing and Cognition Centre at the National University Health System, Singapore and Craig Anderson, Professor of Neurology and Epidemiology, Faculty of Medicine, UNSW, said the results of the current study posed the question of whether preventive treatment needed to be started earlier in life.
“There is good evidence that long-standing midlife hypertension increases the risk of later cognitive impairment and dementia, whereas the association of hypertension and dementia in older age is weak,” they wrote.
“Because the mean age of HOPE-3 participants was >70 years, when rates of dementia are exponentially increasing, it can be argued that it is by then too late to reverse pathophysiologic process arising from a long exposure to cardiovascular risk factors such as hypertension and hyperlipidemia,” they added.
Professor Anderson is also Executive Director of The George Institute China at Peking University Health Science Center in Beijing, China.