Elsevier

American Heart Journal

Volume 188, June 2017, Pages 93-98
American Heart Journal

Clinical Investigation
Atrial fibrillation incrementally increases dementia risk across all CHADS2 and CHA2DS2VASc strata in patients receiving long-term warfarin

https://doi.org/10.1016/j.ahj.2017.02.026Get rights and content

Background

Patients with atrial fibrillation (AF) are at higher risk for developing dementia. Warfarin is a common therapy for the prevention of thromboembolism in AF, valve replacement, and thrombosis patients. The extent to which AF itself increases dementia risk remains unknown.

Methods

A total 6030 patients with no history of dementia and chronically anticoagulated with warfarin were studied. Warfarin management was provided through a Clinical Pharmacy Anticoagulation Service. Patients were stratified by warfarin indication of AF (n = 3015) and non-AF (n = 3015) and matched by propensity score (±0.01). Patients were stratified by the congestive heart failure, hypertension, age >75 years, diabetes, stroke (CHADS2) score calculated at the time of warfarin initiation and followed for incident dementia.

Results

The average age of the AF cohort was 69.3 ± 11.2 years, and 52.7% were male; average age of non-AF cohort was 69.3 ± 10.9 years, and 51.5% were male. Increasing CHADS2 score was associated with increased dementia incidence, P trend = .004. When stratified by warfarin indication, AF patients had an increased risk of dementia incidence. After multivariable adjustment, AF patients continued to display a significantly increased risk of dementia when compared with non-AF patients across all CHADS2 scores strata.

Conclusions

In patients receiving long-term warfarin therapy, dementia risk increased with increasing CHADS2 scores. However, the presence of AF was associated with higher rates of dementia across all CHADS2 score strata. These data suggest that AF contributes to the risk of dementia and that this risk is not solely attributable to anticoagulant use. Dementia may be an end manifestation of a systemic disease state, and AF likely contributes to its progression.

Section snippets

Methods

Patients that were ≥18 years of age, had no history of dementia, and were chronically anticoagulated with warfarin with >1 international normalized ratio measurement (target international normalized ratio of 2-3) for thromboembolism prevention between January 1, 1997, and February 18, 2015, were studied. Patients were analyzed in 2 groups; the first group was patients who were anticoagulated with warfarin for stroke prevention due to AF; the second group was patients using long-term warfarin

Results

The baseline demographics of the overall population stratified by AF and non-AF patients receiving long-term warfarin for thromboembolism prevention are shown in Table I.

Distribution among CHADS2 risk strata was similar among non-AF and AF patients. Results were similar when evaluating by CHA2DS2Vasc strata; however, non-AF indication for warfarin was more prevalent with increasing score (Supplemental Table 1).

A total of 79 (2.6%) non-AF and 156 (5.2%) AF patients developed dementia during 7.7 ± 

Discussion

We observed that dementia rates increase as CHADS2 and CHA2DS2VASc scores increase among all patients receiving long-term warfarin. This finding suggests that, in most patients, dementia, similar to AF, may be an end manifestation of a systemic disease state reflecting multiple cardiovascular risk factors. Patients with elevated CHADS2 or CHA2DS2VASc scores have an increased risk of dementia. The presence of AF added additional risk to the various strata for CHADS2 and CHA2DS2VASc scores. This

Limitations

This is a retrospective, observational study that used a large electronic database warehouse to query the clinical data pertinent for the purpose of identifying relations relevant to this study. There were lower event rates among non-AF patients compared with AF patients; therefore, associations were not always significant. This study relies on physicians to diagnose and document patient diseases with the appropriate ICD-9 and ICD-10 codes. Therefore, there is a risk of disease

Conclusion

In patients who are anticoagulated long term on warfarin, the presence of AF was associated with higher rates and increased risk of dementia across all CHADS2 score strata. Furthermore, escalating CHADS2 scores showed that dementia risk was increased for all patients anticoagulated long term on warfarin. The results of this study highlight that dementia is often an end manifestation of a systemic disease state that is driven by multiple comorbidities and that AF is additive to this process and

References (20)

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