Predicting Alzheimer's Disease and Related Dementias in Heart Failure and Atrial Fibrillation

Fibrinaloid Microclots and Atrial Fibrillation

Atrial fibrillation (AF) is a comorbidity of a variety of other chronic, inflammatory diseases for which fibrinaloid microclots are a known accompaniment (and in some cases, a cause, with a mechanistic basis). Clots are, of course, a well-known consequence of atrial fibrillation. We here ask the question whether the fibrinaloid microclots seen in plasma or serum may in fact also be a cause of (or contributor to) the development of AF. We consider known 'risk factors' for AF, and in particular, exogenous stimuli such as infection and air pollution by particulates, both of which are known to cause AF. The external accompaniments of both bacterial (lipopolysaccharide and lipoteichoic acids) and viral (SARS-CoV-2 spike protein) infections are known to stimulate fibrinaloid microclots when added in vitro, and fibrinaloid microclots, as with other amyloid proteins, can be cytotoxic, both by inducing hypoxia/reperfusion and by other means. Strokes and thromboembolisms are also common consequences of AF. Consequently, taking a systems approach, we review the considerable evidence in detail, which leads us to suggest that it is likely that microclots may well have an aetiological role in the development of AF. This has significant mechanistic and therapeutic implications.

Association Between Catheter Ablation and Dementia Among Patients With Atrial Fibrillation: A Systematic Review and Meta-analysis

Atrial fibrillation (AF) is associated with an increased risk of Dementia. However, the association between catheter ablation (CA) in patients with atrial fibrillation and the risk of dementia is not well established, with conflicting results to date. We aimed to evaluate the association between CA patients and the risk of Dementia. We performed a systematic literature search using the PubMed, Embase, Scopus, and Cochrane libraries for relevant articles from inception until 10th May 2023. Hazard ratios (HR) were pooled using a random-effect model, and a P-value of < 0.05 was considered statistically significant. A total of 5 studies with 125,649 patients (30,192 in the CA group and 95,457 in the non-CA group) were included. The mean age of patients among CA and non-CA groups was comparable (58.7 vs 58.18). The most common comorbidity among CA and non-CA groups was hypertension (18.49% vs 81.51%), respectively. Pooled analysis of primary outcome showed that CA was associated with a significant reduction in the risk of Dementia (HR, 0.63 [95% CI: 0.52-0.77], P < 0.001). Similarly, pooled analysis of secondary outcomes showed that the patients with CA had a lower risk of Alzheimer's disease (HR, 0.78 [95% CI: 0.66-0.92], P < 0.001) compared with the non-CA group. However, there was no statistically significant difference in the risk of vascular dementia (HR, 0.63 [95% CI: 0.38-1.06], P = 0.08) between both groups of patients. Our study suggested that catheter ablation reduced the risk of dementia and Alzheimer's disease compared to the nonablation group of patients.

Early prediction of Alzheimer's disease and related dementias using real-world electronic health records

INTRODUCTION

This study aims to explore machine learning (ML) methods for early prediction of Alzheimer's disease (AD) and related dementias (ADRD) using the real-world electronic health records (EHRs).

METHODS

A total of 23,835 ADRD and 1,038,643 control patients were identified from the OneFlorida+ Research Consortium. Two ML methods were used to develop the prediction models. Both knowledge-driven and data-driven approaches were explored. Four computable phenotyping algorithms were tested.

RESULTS

The gradient boosting tree (GBT) models trained with the data-driven approach achieved the best area under the curve (AUC) scores of 0.939, 0.906, 0.884, and 0.854 for early prediction of ADRD 0, 1, 3, or 5 years before diagnosis, respectively. A number of important clinical and sociodemographic factors were identified.

DISCUSSION

We tested various settings and showed the predictive ability of using ML approaches for early prediction of ADRD with EHRs. The models can help identify high-risk individuals for early informed preventive or prognostic clinical decisions.

Ablation of atrial fibrillation and dementia risk reduction during long-term follow-up: a nationwide population-based study

AIMS

This study investigated the epidemiological characteristics of new-onset dementia in patients with atrial fibrillation (AF) and the association of catheter ablation with different subtypes of dementia.

METHODS AND RESULTS

We conducted a population-based, retrospective cohort study using data from the Taiwan National Health Insurance Research Database. In total, 136 774 patients without a history of dementia were selected after 1:1 propensity score matching based on age (with AF vs. without AF). A competing risk model was used to investigate the three subtypes of dementia: Alzheimer's disease, vascular dementia, and other/mixed dementia. Inverse probability of treatment weighting (IPTW) was performed to minimize the impact on dementia risk due to the imbalanced baseline characteristics. After a median follow-up period of 6.6 years, 8704 events of new-onset dementia occurred. Among all AF patients developing dementia, 73% were classified as having Alzheimer's disease, 16% as having vascular dementia, and 11% as having other/mixed dementia. The cumulative incidence of dementia in AF patients was higher than those without AF (log-rank test: P < 0.001 for both before and after IPTW). In patients with AF undergoing catheter ablation, the total dementia risk decreased significantly [P = 0.015, hazard ratio (HR): 0.74, 95% confidence interval (CI): 0.58-0.94] after multivariable adjustment, but not for the subtype of vascular dementia (P = 0.59, HR: 0.86, 95% CI: 0.49-1.50).

CONCLUSION

Patients with AF have a higher incidence of all types of dementia, including Alzheimer's disease, vascular dementia, and a mixed type of dementia. Alzheimer's disease is less likely to occur in patients with AF undergoing catheter ablation.

Comparing Lookback Periods to Ascertain Alzheimer's Disease and Related Dementias

Claims data are a valuable resource for studying Alzheimer's disease and related dementias (ADRD). Alzheimer's disease and related dementias is often identified using a list of claims codes and a fixed lookback period of 3 years of data. However, a 1-year lookback or an approach using all-available lookback data could be beneficial based on different research questions. Thus, the purpose of this study was to compare 1-year and all-available lookback approaches to ascertaining ADRD compared to the standard 3-year approach. Using a cohort of Veterans hospitalized for heart failure (N = 373, 897), our results suggested high agreement (93% or greater) between the lookback periods. The 1-year lookback period had lower sensitivity (60%) and underestimated the prevalence of ADRD. These results suggest that 1-year and all-available lookback periods are viable approaches when using claims data.