There are significant uncertainties in the optimal management of hypertension in people with dementia. A recent review by Harrison et al, published in the journal Age and Ageing, investigated whether people with dementia experienced greater adverse effects from antihypertensive medications, whether cognitive function was protected or worsened by controlling blood pressure (BP), and if there were subgroups of people with dementia for whom antihypertensive therapy was more likely to be harmful.
People with dementia may be more susceptible to the adverse effects of antihypertensive treatment. Over time, patients with dementia will experience lower drops in systolic and diastolic BP compared with those without dementia.
Orthostatic hypotension has been found in 22 percent of patients with vascular dementia compared with 4 percent of patients with normal cognition. There is also a theoretical risk that overall anticholinergic burden could put individuals with dementia at greater risk of adverse effects from antihypertensive medications.
Whilst hypertension is a risk marker for Alzheimer’s disease, there is limited evidence that orthostatic hypotension is a significant predictor of the conversion of mild cognitive impairment to dementia.
There are significant uncertainties in the optimal management of hypertension in people with dementia
From epidemiological studies, in mid-life, hypertension is a risk factor for dementia. Whereas, in older age, hypotension is associated with greater risk.
The authors discuss extreme old age and frailty as two possible subgroups of patients in which antihypertensive therapy may be more harmful but do acknowledge that there is no clinical trial evidence to support this.
The paper offers clinical advice in the following areas:
Assess carefully: In addition to assessing usual vascular risk factors, ambulatory blood pressure monitoring should be attempted to exclude white-coat hypertension and prolonged hypotension, which may contribute to cerebral hypoperfusion.
Guidelines:The authors found no reason not to adhere to current clinical guidelines, i.e. ESH/ESC recommend reducing BP in older people to 140–150 mmHg and NICE advise a target BP of 140/90 mmHg for those younger than 80 years and 150/90 mmHg for people 80 or older.
Medication choice: One way to reduce medication burden is to select those medicines that have complementary effects. For example, to prescribe a β-blocker for the treatment of hypertension if the individual also requires treatment for atrial fibrillation or to utilise the BP-lowering effects of nitrates or amlodipine which can also used in the treatment of angina.
Different antihypertensive medications could have different effects on cognition. Recent meta-analyses suggest renin-angiotensin-aldosterone system blocking medications and diuretics are associated with a reduced risk of dementia, although the mechanisms for these observed differences are not fully understood.
Deprescribing: The authors state that primary care is best placed to review and deprescribe, outwith episodes of acute illness and where deprescribing is commenced in hospital, careful communication of rationale and treatment objectives is essential.
Reviews may include education around medication indications, communication of the risks and benefits, and establishment of the individual’s goals. Individuals with ‘controlled’ BP may no longer require treatment. However, they should continue to have BP monitored in case they become hypertensive again.
Find the research here:
Harrison JK et al.New horizons: The management of hypertension in people with dementia. Age Ageing. 2016;45(6):740-746.