Atrial Fibrillation and Risk of Dementia/Cognitive Decline

The association between sociodemographic characteristics and dementia in patients with atrial fibrillation

Objectives

Association between socio-demographic factors and dementia risk is studied in general but not for atrial fibrillation (AF) patients.

Methods

We studied AF patients ≥ 45 years in Sweden 1998–2012 (n = 537,513) using the Total Population Register for socio-demographic factors, the Swedish Cause of Death Register, and the National Patient Register (NPR) for incident dementia. Cox regression with hazard ratios (HR) and 95% confidence intervals (CI) was used for the association between exposure and outcome, adjusting for age and comorbidities.

Results

Totally 30,332 patients (5.6%) were diagnosed with dementia during the follow-up (mean 5.4 years). Of these, 14,097 were men (4.9%) and 16,235 were women (6.5%). Lower educational levels (reference: highest level) were associated with increased dementia, HRs (95% CI) for basic school for men 1.23 (1.18–1.29) and women 1.36 (1.30–1.42), and middle-level school for men 1.17 (1.11–1.22) and women 1.28 (1.22–1.34). Divorced men and women (reference: married) showed increased risk of dementia, HR 1.07 (1.01–1.13) and 1.12 (1.06–1.18), respectively, while widowed men showed lower risk, HR 0.84 (0.80–0.88). High deprivation neighborhood socio-economic status (NSES; reference: medium level) was associated with increased dementia in men, HR 1.11 (1.05–1.17), and low deprivation neighborhood socio-economic status (NSES) with increased dementia in men and women, HR 1.12 (1.06–1.18) and 1.18 (1.12–1.24), respectively.

Conclusions

Some results were expected, i.e. association between lower educational level and dementia. The higher risk of dementia in low deprivation NSES-areas could be due to a higher awareness about dementia, and subsequent earlier diagnosis and treatment of dementia.

Electronic supplementary material

The online version of this article (10.1007/s40520-019-01449-3) contains supplementary material, which is available to authorized users.

A self-management support intervention for patients with atrial fibrillation: a randomized controlled pilot trial

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia worldwide. Despite effective treatment, it is characterized by frequent recurrences. Optimal therapeutic management of AF requires active participation and self-management from patients. Two major components of self-management are self-monitoring and sign-and-symptom management. Pulse self-palpation (PSP) is a method of self-monitoring; however, not all AF patients are capable of successfully performing PSP. Due to a lack of interventions on this topic, a nurse-led intervention for patients with AF (PSPAF intervention) was developed to foster self-monitoring and to enhance self-management through PSP. The purpose of this pilot study was to test the acceptability, feasibility, and potential effects of this intervention on the capability of patients' PSP and sign-and-symptom management. Moreover, we aimed at gathering data on the feasibility of applied research methods to aid in the design of future studies.

METHODS

The pilot trial involved 20 adult patients with AF, randomized to an intervention or usual care group. At baseline and during a home visit 3-5 weeks later, we collected data using questionnaires, checklists, field notes, a mobile ECG device, and a diary. Acceptability and feasibility measures were validated through predefined cut-off points. Effect size estimates were expressed as relative risks (RR) and the number needed to treat (NNT).

RESULTS

The PSPAF intervention seemed feasible, but only partly acceptable. There were limitations in terms of potential effectiveness, suitability, addressing participants' willingness to implement its content in daily life, and adherence. Estimations of effect sizes suggest a large effect of the intervention on patients' PSP capability (RR = 6.0; 95% CI = [0.83, 43.3]; NNT = 2.4), but almost no effect on sign-and-symptom management (RR = 1.5; 95% CI = [0.7, 3.1]; NNT = 4.0). The feasibility of applied research methods showed minor limitations on recruitment and participant burden.

CONCLUSIONS

Despite some limitations, the intervention seemed to be applicable and promising. Taking into account the suggestions and amendments we have made, we recommend conducting a full-scale trial to examine the efficacy of the PSPAF intervention.

TRIAL REGISTRATION

This pilot study was registered in the German Clinical Trials Register at September 4, 2017 (Main ID: DRKS00012808).

Inflammatory and Infectious Processes Serve as Links between Atrial Fibrillation and Alzheimer's Disease

Atrial fibrillation (AF) is one of the most prevalent forms of arrhythmia that carries an increased risk of stroke which, in turn, is strongly associated with cognitive decline. The majority of dementia cases are caused by Alzheimer's disease (AD) with obscure pathogenesis. While the exact mechanisms are unknown, the role of inflammatory processes and infectious agents have recently been implicated in both AD and AF, suggesting a common link between these maladies. Here, we present the main shared pathways underlying arrhythmia and memory loss. The overlapping predictive biomarkers and emerging joint pharmacological approaches are also discussed.

Cognitive Screening in Geriatric Patients with Atrial Fibrillation Evaluated for Falls

Background

Atrial fibrillation (AF) is associated with cognitive decline and dementia. This study investigates whether the Montreal Cognitive Assessment (MoCA) detects more cognitive decline than the Mini Mental State Examination (MMSE) in patients with AF. Secondary aims were to assess the rate of white matter hyperintensities (WMH) and mesotemporal atrophy (MTA) in patients with AF.

Methods

Observational cohort study. Patients of 65 years and older that visited the Fall and Syncope Clinic were eligible. Patients were included if both a MoCA and MMSE were completed. In patients of whom an MRI was performed WMH were assessed with the Fazekas score and MTA was assessed with the MTA score. To assess frailty a Frailty Index (FI) was calculated.

Results

428 patients were included. Mean age was 80 years, 66% was female. The mean FI was 0.28 (CI 0.11 to 0.45), indicative of severe frailty. In 90 patients AF was known and in 9 patients it was first diagnosed, overall prevalence 23%. Cognitive impairment was found with the MoCA in 80% of patients with persistent AF, versus in 33% with the MMSE. Patients with paroxysmal AF had more WMH than patients with SR (p 0.04). No differences were found in relevant MTA between patients with AF or SR.

Conclusions

Cognitive decline in patients with AF is better detected using the MoCA than the MMSE. This means that in daily clinical practice, the MOCA should be used instead of the MMSE for patients with AF.

Levothyroxine treatment and incident dementia in adults with atrial fibrillation

OBJECTIVE

Levothyroxine treatment is common among older adults as is atrial fibrillation (AF), yet less is known about its potential effects on the development of dementia.

METHODS

The study population included all adults with diagnosed AF (n = 156,104) aged ≥ 45 years in Sweden without an earlier recorded diagnosis of dementia. Individuals with a dispensed prescription of levothyroxine on two or more occasions between July 1 2005 and December 31 2006 in Sweden were considered exposed (n = 12,978; 8.3%), and were compared to all other patients with AF without this treatment. Cox regression with hazard ratios (HRs) and 95% confidence interval (95% CI), with outcome defined as dementia of all causes between January 1, 2007 and December 31, 2015, was used in the analysis. Adjustments were made for socio-demographic factors (age, immigration status, marital status, educational level, neighborhood socioeconomic status), co-morbidity (cardiovascular disease, obesity, diabetes, COPD, depression, anxiety and alcohol related diagnoses), and cardiovascular medications.

RESULTS

During follow-up, a total of 9054 patients with AF were diagnosed with dementia (5.8%). We found no significant association of levothyroxine treatment and incident dementia, fully adjusted HR 1.03 (95% CI 0.96-1.11), neither among men and women, nor in different age-groups or subgroups of dementia.

CONCLUSION

We found no significant association of levothyroxine treatment and incident dementia among patients with AF, which contrasts some earlier findings.

Association Between Atrial Fibrillation and Dementia: A Meta-Analysis

Background: A potential evidence from previous epidemiological studies remains conflicting findings regarding the association between atrial fibrillation (AF) and dementia risk. We, therefore, carried out a meta-analysis of relevant studies to investigate the magnitude of the association between AF and dementia risk.

Methods: We performed a systematic literature search of PubMed, EMBASE, and Google Scholar for potential studies between January 1, 1990, and December 31, 2018, with no restriction on the publication language. All potential studies were independently assessed by two reviewers. We only included observational studies that calculated the odds ratio (OR)/hazards ratio (HR) for dementia associated with atrial fibrillation. We first assessed the heterogeneity among study-specific HRs using the Q statistic and I² statistic. We then used the random-effects model to obtain the overall HR and its 95% CI for all studies. We also tested and corrected for publication bias by funnel plot–based methods. The quality of each study was assessed with the Newcastle Ottawa Scale.

Results: A total of 16 studies with 2,415,356 individuals, and approximately 200,653 cases of incidence dementia were included in this study. Patients with AF had a greater risk of incidence dementia than those without AF (random-effect hazard ratio HR: 1.36, 95% CI: 1.23–1.51, p < 0.0001; I² = 83.58). Funnel plot and Egger test did not reveal significant publication bias. However, limitations of the study included high heterogeneity and varying degrees of confounder adjustment across individual studies.

Conclusion: This study serves as added evidence supporting the hypothesis that AF is associated with an increased risk of dementia. More studies are needed to establish whether optimal treatment of AF can reduce or mitigate the risk of dementia.

Effect of Levothyroxine Treatment on Incident Dementia in Adults with Atrial Fibrillation and Hypothyroidism

Background and Objective

The possible adverse or positive effects of levothyroxine treatment among patients with atrial fibrillation have been debated. Atrial fibrillation, levothyroxine treatment, and dementia are common among older adults, yet little is known about the effects of levothyroxine on the development of dementia.

Methods

The study population included all adults (n = 12,057) aged ≥ 45 years with a diagnosis of atrial fibrillation at 75 primary care centers in Sweden during 2001–2007 without an earlier recorded dementia diagnosis. Patients with a diagnosis of hypothyroidism and levothyroxine prescription (n = 756; 180 men and 576 women), or with a prescription without this diagnosis (n = 415, 100 men and 315 women), were compared to patients without a diagnosis and prescription (n = 10,886). Cox regression was performed, with hazard ratios and 95% confidence intervals, with outcome defined as dementia of all causes until 31 December, 2010.

Results

During a mean 5.7 years (standard deviation 2.4 years) of follow-up, a total of 749 patients with atrial fibrillation (6.2%) were diagnosed with dementia. Women with hypothyroidism and a levothyroxine prescription showed lower hazard ratios (0.61; 0.41–0.90) in adjusted Cox regression models (age, socioeconomic factors, co-morbidity, and warfarin treatment). Levothyroxine prescription without hypothyroidism was non-significant.

Conclusions

We found that women with atrial fibrillation with levothyroxine treatment and hypothyroidism have a lower risk of incident dementia than women with atrial fibrillation without levothyroxine treatment and no hypothyroidism. The results should be confirmed in larger studies.

Electronic supplementary material

The online version of this article (10.1007/s40261-018-0740-3) contains supplementary material, which is available to authorized users.

Modulation of miR-10a-mediated TGF-β1/Smads signaling affects atrial fibrillation-induced cardiac fibrosis and cardiac fibroblast proliferation

Atrial fibrillation (AF) rat models and rat cardiac fibroblasts (CFs) with overexpressed or inhibited miR-10a were used to investigate the possible role of miR-10a-mediated transforming growth factor-β (TGF-β1)/Smads signaling in cardiac fibrosis and fibroblast proliferation in rats with AF. Gene ontology and pathway enrichment analyses were used to identify the possible function of miR-10a in cardiac fibrosis. The results showed that overexpressed miR-10a significantly prolonged the duration of AF, further elevated the collagen volume fraction (CVF), and increased the viability of CFs in AF rats; these findings were in contrast with the findings for rats with inhibition of miR-10a (all P<0.05). Moreover, miR-10a overexpression could promote miR-10a, collagen-I, collagen III, α-SMA, and TGF-β1 protein expression and increase the levels of hydroxyproline but reduced Smad7 protein expression in atrial tissues and CFs in AF rats. Not surprisingly, inhibiting miR-10a led to completely contrasting results (all P<0.05). Moreover, TGF-β1 treatment could reverse the inhibitory effect of miR-10a down-regulation on cardiac fibrosis in CFs. Bioinformatics analysis and luciferase reporter assay results demonstrated that miR-10a bound directly to the 3′-UTR of BCL6, which is involved in cell growth and proliferation. Thus, our study indicate that down-regulation of miR-10a may inhibit collagen formation, reduce atrial structure remodeling, and decrease proliferation of CFs, eventually suppressing cardiac fibrosis in AF rats via inhibition of the TGF-β1/Smads signaling pathway.

Atrial Fibrillation and Objective Sleep Quality by Slow Wave Sleep

BACKGROUND

Self-reported poor sleep quality has been suggested in patients with AF. Slow wave sleep (SWS) is considered the most restorative sleep stage and represents an important objective measure of sleep quality. The aim of this study was to compare quantity of SWS between patients with and without AF.

METHODS AND RESULTS

We included patients with and without a documented history of AF by reviewing clinically indicated polysomnography data from a single sleep center. Patients on medications with potential influence on sleep architecture were excluded. Logistic regression was performed to determine the association between AF and SWS time (low vs. high) adjusting for age, gender, body mass index, and sleep apnea. In a 2:1 case-control set-up, a total of 205 subjects (139 with AF, 66 without AF) were included. Mean age was 62 (SD: 14.3) years and 59% were men. Patients with AF had lower SWS time (11.1 vs. 16.6 min, p=0.02). In multivariable analysis, prevalent AF was associated with low SWS independent of sleep apnea and other potential confounders (OR 2.5 [1.3, 5.0], p=0.006). Limiting the analysis to patients whose total sleep time was greater than 4 hours (by excluding N=31) resulted in more robust results (OR 3.9 [1.7, 9.7]. p=0.002).

CONCLUSION

AF is associated with more impaired sleep quality as indicated by lower quantity of SWS. More studies are needed to explore the mechanistic interactions between AF and sleep.

The association between relevant comorbidities and dementia in patients with atrial fibrillation

Risk of dementia is increased in patients with atrial fibrillation (AF). We aimed to study associations between relevant comorbidities and prevalent as well as incident dementia in AF patients. Study population included all adults (n = 12,283) ≥ 45 years diagnosed with AF at 75 primary care centers in Sweden 2001-2007. Logistic regression was used to calculate odds ratios (OR) with 95% confidence intervals (95% CI) for associations between comorbidities and prevalent dementia. In a subsample (n = 12,096), (excluding patients with dementia diagnosed before AF onset), Cox regression was used to estimate hazard ratios (HR) with 95% CIs for association between comorbidities, and incident dementia, after adjustment for age, socioeconomic factors and anticoagulant treatment. Totally 937 patients (7.6%), 388 men (5.8%) and 549 women (9.7%), were diagnosed with dementia. After adjustments, prevalent dementia was more common in (ORs, 95% CI) men with congestive heart failure (CHF), stroke, and depression; in women with CHF and depression, and among women > 75 years with stroke, but less common in women with hypertension. During a 5.6-year follow-up (standard deviation 2.5), 750 patients (6.2%; 322 men, 4.9%, and 428 women, 7.8%) were diagnosed with incident dementia. An increased risk of incident dementia was found among men with diabetes and depression; a decreased risk among men and women with CHF, and among women with hypertension, myocardial infarction cerebrovascular diseases. The findings regarding incident dementia need to be interpreted with great caution, as they may have been subject to survival bias.

Association between insomnia and atrial fibrillation in a Chinese population: A cross-sectional study

BACKGROUND

Insomnia is the most prevalent sleep disorder; however, little research has explored the link between insomnia and atrial fibrillation (AF).

HYPOTHESIS

Insomnia is associated with increased risk of AF in a Chinese population.

METHODS

A total of 8371 Chinese participants (4314 males; mean age, 42.4 ± 13.1 years) were enrolled in this cross-sectional study to investigate the association between insomnia and AF. AF was assessed in a standard supine resting position with a 10-s 12-lead electrocardiograph (ECG) or by self-reported history. Insomnia was assessed using the Athens Insomnia Scale (AIS), and a score of ≥6 was regarded as having insomnia. The association between insomnia and AF was determined by logistic regression analysis.

RESULTS

Among the 8371 subjects, 1074 (12.8%) had different degrees of insomnia, and AF was observed in 50 subjects (0.60%). After adjusting for potential confounders, individuals with insomnia had moderately increased likelihood of suffering from AF compared with those without insomnia (odds ratio [OR]: 1.92, 95% confidence interval [CI]: 1.00-3.70, P = 0.05). After stratifying data by age, a significant positive association was found in those age <40 years (OR: 6.52, 95% CI: 1.64-25.83, P = 0.01), and a similar trend existed in males after stratifying by sex, although this relationship was not statistically significant (OR: 2.11, 95% CI: 0.92-4.83, P = 0.08).

CONCLUSIONS

Individuals with insomnia may have a higher risk of AF in the particular Chinese population assessed in this study. Age (<40 years) is a significant factor in the association between insomnia and AF.