Warfarin treatment and risk of stroke among primary care patients with atrial fibrillation

The association between gout and cardiovascular disease in patients with atrial fibrillation

Objective

Gout is a sign of a disturbed metabolism and associated with atrial fibrillation (AF) and other cardio-vascular diseases. Our aim was to study associations between gout and cardiovascular co-morbidities in patients with AF.

Methods

The study population included all adults (n=12,283) ≥45 years diagnosed with AF visiting 75 primary care centers in Sweden 2001-2007. Logistic regression was used to calculate odds ratios with 95% confidence intervals (CIs) for the associations between prevalent gout and cardiovascular co-morbidities. In subsamples we studied incident congestive heart failure (CHF) and ischemic stroke (IS), excluding patients with earlier registered specific diagnosis, using Cox regression (to estimate hazard ratios (HR) with 95% CIs).

Results

Gout was significantly and positively associated with CHF, obesity and diabetes among men and women, and among men also with hypertension and coronary heart disease. Prevalent gout was negatively associated with incident IS (HR and 95% CI: 0.64, 0.49-0.82; 0.50, 0.39-0.64) in both full model (adjusted for sex, age, socio-economic factors and comorbidities) and CHA₂DS₂-VASc model (adjusted for CHA₂DS₂-VASc, sex and age). Adding gout to full model increased Harrell's C by 1% in CHA₂DS₂-VASc model.

Conclusions

In this clinical setting we found gout to be associated with most cardiometabolic diseases except cerebrovascular diseases, and with decreased risk of IS, with gout adding significantly to the predictive value compared to CHA₂DS₂-VASc without gout included.

Sex differences in stroke and major adverse clinical events in patients with atrial fibrillation: A systematic review and meta-analysis of 993,600 patients

BACKGROUND

Atrial fibrillation (AF) is the most commonly diagnosed arrhythmia, which is associated with an increased risk of stroke. Several studies have suggested that female AF patients could have a greater risk for stroke and thromboembolic events (TE).

METHODS

A systematic literature review update and meta-analysis was conducted using Pubmed. The search used the terms "atrial fibrillation", "gender", "sex", "female", "women", "stroke", "thromboembolism". Main aim of the study was to compare and male AF patients for occurrence of stroke and TE. Secondary outcomes were: major bleeding, cardiovascular (CV) death and all-cause death.

RESULTS

Forty-four studies were included in the analysis including 993,603 patients (48.9% women). After pooling the data, there was a higher risk of stroke for women vs. male AF patients (hazard ratio [HR]: 1.24; 95% confidence intervals [CIs]: 1.14-1.36). Overall, TE risk was not different between female and male patients, despite sensitivity analysis left some uncertainties. No sex differences were found for major bleeding, CV death and all-cause death. A significant relationship between increasing age and the difference in stroke risk between female and male AF patients was found (Delta HR: 1.01; 95% CI: 1.00-1.03 for each year of age increase).

CONCLUSIONS

Female patients with AF are at increased risk of stroke compared to men. A significant relationship between increasing age and stroke risk in women compared to men was found, most evident at age > 65 years. Female sex may act as a stroke risk modifier, particularly in elderly and very elderly AF subjects, conferring a significant increase in stroke risk.

Dabigatran affects thrombin-dependent platelet aggregation after a week-long therapy

OBJECTIVE

Dabigatran is a direct thrombin inhibitor. As the main adverse event is bleeding, it is relevant whether dabigatran has additional effects on platelet function. If so, it could affect the bleeding risk. We aimed to assess in vitro aggregation in patients with atrial fibrillation (AF) receiving dabigatran.

DESIGN

We evaluated 32 AF patients treated with dabigatran (study group) and 18 non-anticoagulated non-AF blood donors (control group). We assessed light transmittance platelet aggregation (LTA) with 100 nmol/L γ-thrombin in both groups. The LTA was performed at two time-points in our dabigatran group of patients.

RESULTS

The thrombin-induced platelet aggregation was significantly lower two hours after dabigatran was taken compared to baseline measurement (9% ± 6% vs. 29% ± 21%) in our study group. Moreover, we observed that the baseline value of platelet aggregation in patients on dabigatran treatment was significantly lower compared to healthy volunteers (29% ± 21% vs. 89 ± 8). However, one subanalysis showed that this significant reduction in platelet aggregation at baseline was only observed in patients who received dabigatran for over a week.

CONCLUSION

The thrombin-induced platelet aggregation is reduced in non-valvular AF patients receiving dabigatran after a week-long therapy.

Monotherapy of acetylsalicylic acid or warfarin for prevention of ischemic stroke in low-risk atrial fibrillation: A Easter Asian population-based study

BACKGROUND

This study aimed to investigate the effectiveness of monotherapy acetylsalicylic acid (ASA) and warfarin for stroke prevention in low-risk atrial fibrillation (AF) by using a population- -based cohort study in Taiwan.

METHODS

A newly diagnosed low-risk AF patient cohort were identified by using National Health Insurance Research Database (NHIRD) in Taiwan in 2008. The study cohort was observed with a follow-up of 2 years to examine the onset of ischemic stroke (IS) (to 2010). The longitudinal data were analyzed by using generalized estimation equations (GEE).

RESULTS

A total of 8,065 newly-diagnosed low-risk AF patients were identified in 2008. 7.4% were prescribed with ASA and 4.6% were prescribed with warfarin. The GEE results showed that low-risk AF patients with hypertension who received warfarin were associated with a statistically significant 58.4% reduction of IS risk (OR = 0.416, p = 0.024, 95% CI 0.194-0.891). Additionally, low-risk AF patients with hyperlipidemia who received warfarin were associated with a 69.3% reduction of IS risk (OR = 0.307, p = 0.044, 95% CI 0.097-0.969).

CONCLUSIONS

Warfarin is suggested to be prescribed in preventing IS for low-stroke-risk AF patients with hypertension and hyperlipidemia.

Mortality in patients with atrial fibrillation and common co-morbidities - a cohort study in primary care

OBJECTIVE

To study the association between cardiovascular co-morbidities and mortality risk in primary care patients with atrial fibrillation.

METHODS

The study population included all adults (n = 12,283) ≥ 45 years diagnosed with AF at 75 primary care centres in Sweden between 2001 and 2007. The outcome was mortality (until 2010) and data were explored for co-morbidities using Cox regression with hazard ratios (HRs). Analyses were performed stratified by sex and by age-group (45-64, 65-74 and ≥75 years of age) with adjustment for age, socio-economic factors and relevant co-morbidities.

RESULTS

During a mean of 5.8 years (standard deviation 2.4) of follow-up, 3954 (32%) patients died (1971 (35%) women, and 1983 (30%) men). High HRs were found for congestive heart disease (CHF) and cerebrovascular diseases for all age-groups among men and women (except for the 45-64 year old women); for coronary heart disease among the oldest men; for diabetes among the 65-74 year old men and the 45-64 year old women. Low HRs were found for hypertension among women ≥75 years of age.

CONCLUSIONS

In this clinical setting, CHF and cerebrovascular diseases were consistently associated with mortality in all age-groups. The possible protective effect by hypertension among elderly women should be interpreted with caution. KEY MESSAGES We found congestive heart failure and cerebrovascular diseases to be consistently associated with mortality in both women and men. We found hypertension to be associated with lower mortality risk among women ≥75 years of age, although this finding must be interpreted with caution. Depression was found to be associated with increased mortality risk among men and women aged 65-74 years of age.

Association between antithrombotic treatment and hemorrhagic stroke in patients with atrial fibrillation-a cohort study in primary care

Objective

The objective of this study was to study the association between antithrombotic treatment and risk of hemorrhagic stroke (HS) in patients with atrial fibrillation (AF) treated in primary health care.

Methods

Study population included all adults (n = 12,215) 45 years and older diagnosed with AF at 75 primary care centers in Sweden 2001–2007. Outcome was defined as a first hospital episode with a discharge episode of HS after the AF diagnosis. Association between HS and persistent treatment with antithrombotic agents (warfarin, acetylsalicylic acid (ASA), clopidogrel) was explored using Cox regression analysis, with hazard ratios (HRs) and 95 % CIs. Adjustment was made for age, socioeconomic status, and co-morbid cardiovascular conditions.

Results

During a mean of 5.8 years (SD 2.4) of follow-up, 162 patients (1.3 %; 67 women and 95 men) with HS were recorded. The adjusted risk associated with persistent warfarin treatment compared to no antithrombotic treatment consistently showed no increased HS risk, HR for women 0.53 (95 % CI 0.23–1.27) and for men 0.55 (95 % CI 0.29–1.04); corresponding HRs for ASA were, for women, 0.45 (95 % CI 0.14–1.44) and, for men, 0.56 (95 % CI 0.24–1.29).

Conclusions

In this clinical setting, we found no evidence pointing to an increased risk of HS with antithrombotic treatment.

Electronic supplementary material

The online version of this article (doi:10.1007/s00228-016-2152-8) contains supplementary material, which is available to authorized users.