Middle Age Prevention of Future Alzheimer’s Disease and Related Dementias with Intensive Treatment of Hypertension: Middle PATH Clinical Trial Proposal

Abstract

AbstractStrong epidemiological evidence from multiple studies suggests that elevated systolic blood pressure (SBP) in midlife is a risk factor for Alzheimer’s disease and Related Dementias (ADRD) later in life. The most common neuropathology of biomarker‐confirmed AD is combined AD neuropathological changes and cerebrovascular disease. Hypertension is a leading cause of cerebrovascular disease. The SPRINT MIND trial demonstrated that a goal SBP<120 mm Hg reduced risk for combined mild cognitive impairment (MCI) and dementia by 15% in older individuals compared to a goal SBP<140 mm Hg. SBP can be safely treated with inexpensive medications. Despite being potentially safe and cost‐effective, with strong supporting evidence for benefit, intensive SBP lowering in midlife to reduce future ADRD risk has never been studied, likely because clinical outcomes of MCI and dementia are not practical in this age range in a trial that is usually limited to about 5 years. Elevated SBP is a major risk factor for white matter hyperintensity volume (WMHV) accumulation, an MRI marker with extensive evidence demonstrating this to be associated with and predictive of incident ADRD, making WMHV a suitable surrogate outcome for the initial trial period. While we acknowledge the challenges of using a surrogate outcome, there is no suitable alternative when testing interventions to lower future ADRD risk starting in middle age, a strategy that we believe is essential. The Alzheimer’s Prevention Initiative and Wake Forest have formed a collaboration to investigate the effect of goal SBP<120 mm Hg compared to the SBP achieved by enhanced usual care (SBP≥135 mm Hg) on annualized rate of WMHV accumulation in persons ages 45‐65 who have some existing vascular risk at baseline. Secondary outcomes of changes in AD blood biomarkers and relevant cognitive test scores will help elucidate whether and how SBP and AD are interactive or independent deleterious pathophysiological processes. The intention, should the initial phase prove successful, is to continue and expand the trial until a clinical benefit can definitively be assessed.