Class-Specific Antihypertensives and Alzheimer's Disease: Genotype- and Hypertension-Stratified Analysis.

Antihypertensive medications (AHMs) may modulate Alzheimer's disease (AD) pathogenesis via cerebrovascular or neuroinflammatory pathways, yet evidence remains conflicting. This study investigated causal associations between AHM use and AD risk, focusing on drug classes, blood pressure status, and apolipoprotein E epsilon 4 (APOE ε4) effects. We integrated genetic causal inference with longitudinal survival analyses in a dual-evidence framework. Mendelian randomization (MR) was used to estimate class-specific causal effects at the population level. To examine effect modification by genetic and clinical factors, we analyzed 532 cognitively normal or mildly impaired older adults in ADNI with baseline assessments, with time-to-AD conversion modeled using Cox regression stratified by hypertension history and APOE ε4 status. Overall antihypertensive use showed no significant association with AD risk in hypertensive individuals (HR = 0.71) or APOE ε4 carriers (HR = 0.72). However, ARBs demonstrated protective associations in APOE ε4 carriers (HR = 0.32, 95% CI: 0.12-0.86). MR analysis supported causal protective effects for angiotensin II receptor blockers (ARBs, OR = 0.94, 95% CI: 0.89-0.98), calcium channel blockers (CCBs, OR = 0.93, 95% CI: 0.90-0.97), and beta-blockers (BBs, OR = 0.92, 95% CI: 0.86-0.98), whereas ACEIs lacked MR support and thiazide diuretics showed no benefit. Our findings reveal class-specific antihypertensive effects on AD risk. ARBs demonstrated the strongest protection, particularly in APOE ε4 carriers, while BBs and CCBs showed neuroprotective benefits. Results suggest AD prevention involves mechanisms beyond blood pressure reduction alone, supporting precision medicine with genotype-guided antihypertensive selection for genetically vulnerable individuals.