Falcone, Guido J.

Importance The APOE ε4 variant is causally linked to cerebral amyloid angiopathy and is a risk factor for intracranial hemorrhage (ICH) among warfarin-treated patients with atrial fibrillation. Nevertheless, its impact on those treated with apixaban remains unknown. Objective To test the hypothesis that APOE ε4 allele carriership is associated with an increased risk of ICH in patients with atrial fibrillation taking apixaban. Design, Setting, and Participants This cohort study involved data from the All of Us Research Program, a longitudinal, population-based study in the United States. Inclusion criteria were age older than 50 years, history of atrial fibrillation, and anticoagulation with apixaban. Participants with a history of ischemic stroke or ICH were excluded. Up to 3 years of follow-up data were available. Data were collected from 2017 to 2022 and analyzed from November 2023 to December 2024. Exposure APOE ε2, ε3, and ε4 were ascertained using variants rs429358 and rs7412. APOE ε4 was modeled dichotomously (noncarriers [no alleles] vs carriers [1 or 2 alleles]). Main Outcomes and Measures Incident ICH, including any new intraparenchymal, subdural, or subarachnoid hemorrhage after initiation of apixaban therapy. Results Of 413 477 All of Us participants, 2038 were eligible. Their mean (SD) age was 71 (9) years; 918 (45%) were female, 1120 (55%) were male, and 1710 (83%) had European ancestry. Among these participants, 483 (23.7%) were carriers of at least 1 APOE ε4 allele. After a median follow-up of 2.9 years, 26 participants sustained an ICH (cumulative incidence, 1.5%; 95% CI, 1.0%-2.2%), of whom 12 (cumulative incidence, 3.1%; 95% CI, 1.7%-5.3%) were carriers and 14 (cumulative incidence, 1%; 95% CI, 0.6%-1.7%) were noncarriers ( P = .007). Multivariable Cox proportional hazard models confirmed this association: compared with noncarriership, APOE ε4 carriership was associated with a 3-fold increase in the risk of ICH (hazard ratio, 3.07; 95% CI, 1.42-6.65). APOE information improved the discrimination of risk prediction scores (C statistic of 0.74 and 0.68 for models with and without APOE , respectively; P = .03). Conclusions and Relevance Further research is needed to evaluate whether cerebral amyloid angiopathy mediates the observed association and whether APOE e4 information improves clinical decision-making about anticoagulation therapy in patients with atrial fibrillation. The latter is important now that APOE information is used in clinical settings to guide antiamyloid treatment for Alzheimer disease and has been returned to millions of persons by direct-to-consumer genotyping companies.

Introduction: Coagulation factor XI (FXI) inhibitors have shown a better safety profile than other anticoagulants, offering similar reductions in ischemic stroke (IS) risk with a lower risk of intracerebral hemorrhage (ICH). The APOE ε4 genotype is associated with increased risks of both IS and ICH, likely due to its effects on lipid levels, intracranial atherosclerosis, and cerebral amyloid angiopathy. We hypothesized that APOE ε4 carriers would gain greater therapeutic benefit from genetically reduced FXI levels compared to non-carriers. Methods: We conducted a two-stage Mendelian randomization (MR) analysis using the random-effects, inverse-variance weighted method. First, we estimated the effect of genetically proxied FXI inhibition on IS and ICH risk in the general population using summary data from genome-wide association studies of FXI levels (16,169 participants), IS (1,503,898 controls and 110,182 cases), and ICH (3,745 controls and 3,226 cases). Second, we performed stratified analyses to estimate the effect of genetically determined FXI levels on IS (10,343 cases and 476,838 controls) and ICH (2,236 cases and 484,945 controls) risk across APOE ε4 carriership strata (0, 1, or 2 alleles) using UK Biobank data. Results: In the general population, random-effects, inverse-variance weighted MR analyses showed that every 1 unit decrease in natural log-transformed FXI levels was associated with a 37% reduction in IS risk (OR:0.63; 95%CI:0.52–0.77; p <0.001) without a significant increase in ICH risk (OR:0.86; 95%CI:0.37–2.00; p =0.73). Stratified MR analyses indicated that genetically determined reductions in FXI levels had varying protective effects on IS risk based on APOE ε4 status: 31% in non-carriers (OR:0.69, 95%CI:0.53–0.91; p =0.008), 43% in carriers of 1 allele (OR:0.57, 95%CI:0.36–0.91; p =0.02), and 75% in carriers of 2 alleles (OR:0.25, 95%CI:0.06–1.06; p =0.06). Similar MR analyses showed no significant increase in ICH risk with genetically determined reductions in FXI levels in any APOE ε4 strata (all p >0.38, Figure 1). Conclusion: This two-stage genetic study provides causal evidence that lower FXI levels reduce IS risk in the general population, with an even stronger effect among APOE ε4 carriers, while not increasing ICH risk. These results indicate that FXI inhibitors might be a safer and more effective alternative to other anticoagulants among APOE ε4 carriers, who are known to be at higher risk for both ischemic and hemorrhagic events.

ImportanceStroke is a leading cause of death and disability in the US. Accurate and updated measures of stroke burden are needed to guide public health policies.ObjectiveTo present burden estimates of ischemic and hemorrhagic stroke in the US in 2019 and describe trends from 1990 to 2019 by age, sex, and geographic location.Design, Setting, and ParticipantsAn in-depth cross-sectional analysis of the 2019 Global Burden of Disease study was conducted. The setting included the time period of 1990 to 2019 in the US. The study encompassed estimates for various types of strokes, including all strokes, ischemic strokes, intracerebral hemorrhages (ICHs), and subarachnoid hemorrhages (SAHs). The 2019 Global Burden of Disease results were released on October 20, 2020.ExposuresIn this study, no particular exposure was specifically targeted.Main Outcomes and MeasuresThe primary focus of this analysis centered on both overall and age-standardized estimates, stroke incidence, prevalence, mortality, and DALYs per 100 000 individuals.ResultsIn 2019, the US recorded 7.09 million prevalent strokes (4.07 million women [57.4%]; 3.02 million men [42.6%]), with 5.87 million being ischemic strokes (82.7%). Prevalence also included 0.66 million ICHs and 0.85 million SAHs. Although the absolute numbers of stroke cases, mortality, and DALYs surged from 1990 to 2019, the age-standardized rates either declined or remained steady. Notably, hemorrhagic strokes manifested a substantial increase, especially in mortality, compared with ischemic strokes (incidence of ischemic stroke increased by 13% [95% uncertainty interval (UI), 14.2%-11.9%]; incidence of ICH increased by 39.8% [95% UI, 38.9%-39.7%]; incidence of SAH increased by 50.9% [95% UI, 49.2%-52.6%]). The downturn in stroke mortality plateaued in the recent decade. There was a discernible heterogeneity in stroke burden trends, with older adults (50-74 years) experiencing a decrease in incidence in coastal areas (decreases up to 3.9% in Vermont), in contrast to an uptick observed in younger demographics (15-49 years) in the South and Midwest US (with increases up to 8.4% in Minnesota).Conclusions and RelevanceIn this cross-sectional study, the declining age-standardized stroke rates over the past 3 decades suggest progress in managing stroke-related outcomes. However, the increasing absolute burden of stroke, coupled with a notable rise in hemorrhagic stroke, suggests an evolving and substantial public health challenge in the US. Moreover, the significant disparities in stroke burden trends across different age groups and geographic locations underscore the necessity for region- and demography-specific interventions and policies to effectively mitigate the multifaceted and escalating burden of stroke in the country.

Background: Epsilon (e) variants in the Apolipoprotein E (APOE) gene are well-established risk factors for spontaneous intracerebral hemorrhage (s-ICH). We tested the hypothesis that APOE-e variants are also associated with warfarin-related ICH (w-ICH) and examined interactions between APOE and warfarin. Methods: Prospective multicenter 2-stage (discovery and replication) study. ICH was classified as lobar and non-lobar based on admission head CT. In the discovery stage, w-ICH cases were matched with warfarin-exposed controls (w-controls). In replication, w-ICH cases were matched with non-warfarin controls (nw-controls). APOE was directly genotyped. Association testing was performed using multivariable logistic regression. Gene-environment interaction between APOE and warfarin was formally tested using a case only approach (combining s-ICH and w-ICH cases). Results: The discovery stage included 316 w-ICHs (43% lobar and 57% non-lobar) and 355 w-controls. Results are presented in the Table: APOE-e2 was associated with lobar and non-lobar w-ICH, and APOE-e4 was associated with lobar but not with non-lobar w-ICH. In case-only analysis, 885 s-ICHs were combined with w-ICHs (total n=1201) and no evidence of interaction between APOE and warfarin was found (all p>0.20). The replication included 63 w-ICHs (44% lobar and 56% non-lobar) and 990 nw-controls. The distribution of APOE variants was similar in w-controls (discovery) and nw-controls (replication) for both e2 (p=0.81) and e4 (p=0.88). In replication, APOE-e2 and e4 were associated with lobar but not with non-lobar w-ICH. Conclusions: APOE-e variants constitute strong risk factors for lobar w-ICH. An effect may also exist between APOE-e2 and non-lobar hemorrhages, but given the lack of replication larger sample sizes are required to properly assess this association. APOE exerts its effect independently of warfarin, although power limitations render this absence of interaction preliminary.

Purpose: Intracerebral hemorrhage (ICH) is the acute manifestation of a progressive disease of the cerebral small vessels. The severity of this disease appears to influence not only risk of ICH, but also the size of the hematoma. As the burden of high blood pressure(BP)-associated alleles is associated with hypertension-related end-organ damage, we sought to determine if this burden influences ICH admission hematoma volume (AHV). Methods: Prospective study undertaken in 441 ICH patients of European ancestry (210 deep and 231 lobar intracranial hematomas). Forty-three single-nucleotide polymorphisms (SNPs) known to be associated with high BP were genotyped in Illumina610-Quad. Single-SNP association analyses with AHV were performed using linear regression. Subsequently, a genetic risk score was calculated as the sum of the products generated by multiplying, at each of the 43 loci, the number risk alleles times the reported effect of that allele on BP. The score was utilized as the independent variable of univariate and multivariate regression models for 2 outcomes: AHV and poor clinical outcome (modified Rankin Scale 3-6). Principal components analysis was utilized to account for population structure. Results: Individually assessed, no single SNP was associated with AHV. In univariate linear regression, the genetic risk score was associated with AHV in all (deep and lobar) and deep locations (Figure 1), but not in lobar hemorrhages. In multivariate regression analyses, each additional standard deviation of the genetic risk score increased mean deep AHV by 21% (or 2.7-milliliter increase, beta=0.21, standard error=0.08, p=0.01) and risk poor clinical outcome by 55% (odds ratio=1.55, 95% confidence interval 1.05-2.28, p=0.03). No significant associations were observed when considering all (deep and lobar) and lobar hemorrhages. Conclusion: In deep ICH, increasing numbers of high BP-related alleles are associated with larger AHV and poor clinical outcome.

Background: Intracerebral hemorrhage (ICH) is the stroke subtype with the worst prognosis and has no established acute treatment. ICH is classified as lobar and non-lobar based on the location of the hemorrhage, with genetic variation contributing to risk of both subtypes. We report the first genome wide association study (GWAS) of this condition. Methods: The discovery phase included GWAS data (Illumina 610 or Affymetrix 6.0) from 6 ICH studies that enrolled subjects of European ancestry in the US and Europe. Cases were classified as lobar or non-lobar ICH based on head CT. ICH-free controls were selected from ambulatory clinics or by random digit dialing. Standard quality controls filters were applied and principal component analysis was used to account for population structure. Unobserved genotypes were inferred by imputation to 1000 genomes references panels. Association testing was carried out using logistic regression, assuming additive effects, and including age, gender and principal components in the model. Meta-analyses were completed using the inverse normal method, weighting by sample size. Replication of signals with p<1x10E-6 was pursued in an independent multi-ethnic study utilizing direct genotyping. Results: The discovery phase included 1545 cases (664 lobar and 881 non-lobar) and 1481 controls, and tested 5,358,103 SNPs. Two loci were identified: for lobar ICH, an intergenic region located on chromosome 12q21.1 (rs11179580: minor allele frequency [MAF] 0.22, OR 1.54, 95% CI 1.33 - 1.84; p = 6.7x10E-8); and for non-lobar ICH, a region on chromosome 1q22 encompassing the PMF1 and SLC25A44 genes (rs2984613: MAF 0.31, OR 1.45, 95% CI 1.2 - 1.64; p = 8.9x10E-9). Replication included 1256 cases (329 whites, 506 blacks and 421 Hispanics) and 760 controls (237 whites, 346 blacks and 177 Hispanics) and confirmed both loci: 12q21.1 (p = 0.037, meta-analysis p = 2.3x10E-8) and 1q22 (p = 3.0x10E-4, meta-analysis p = 2.2x10E-11). Conclusions: Two new susceptibility loci for ICH were identified, both showing location-specificity. These results confirm the presence of biological heterogeneity across ICH subtypes and highlight that different genetic risk factors may contribute to the small vessel diseases that underlie each ICH subtype.