Background: To examine the effect of intensive blood pressure control on the occurrence of subtypes of mild cognitive impairment (MCI) and determine the risk of progression to dementia or death. Methods: Secondary analysis of a randomized trial of community-dwelling adults (≥50 years) with hypertension. Participants were randomized to a systolic blood pressure (SBP) goal of <120 mm Hg (intensive treatment; n = 4678) or <140 mm Hg (Standard treatment; n = 4683). Outcomes included adjudicated MCI, MCI subtype (amnestic, non-amnestic, multi-domain, single domain), and probable dementia. Multistate survival models were used to examine transitions in cognitive status accounting for the competing risk of death. Results: Among 9361 randomized participants (mean age, 67.9 years; 3332 women [35.6%]), 640 participants met the protocol definition for MCI, with intensive treatment reducing the risk of MCI overall (hazard ratio [HR], 0.81 [95% confidence interval {CI}, 0.69–0.94]), as previously reported. This effect was largely reflected in amnestic subtypes (HR, 0.78 [95% CI, 0.66–0.92]) and multi-domain subtypes (HR, 0.78 [95% CI, 0.65–0.93]). An adjudication of MCI, as compared with normal cognitive function, substantially increased the probability of progressing to probable dementia (5.9% [95% CI: 4.5%–7.7%] vs. 0.6% [95% CI: 0.3%–0.9%]) and to death (10.0% [95% CI: 8.3%–11.9%] vs. 2.3% [95% CI: 2.0%–2.7%]) within 2 years. Conclusions: Intensive treatment reduced the risk for amnestic and multi-domain subtypes of MCI. An adjudication of MCI was associated with increased risk of progression to dementia and death, highlighting the relevance of MCI as a primary outcome in clinical and research settings.
