Our study showed that the 1-year incidence of stroke among patients with atrial fibrillation was 3.1%. A study performed in Jordan showed that the one-year risk of stroke/systemic embolization was 4.5% [12]. This finding is in line with the results of previous studies [18–20]. The lower 1-year incidence of stroke (< 2%) was reported by previous studies in patients with lower CHA2DS2-VASc score [21]. The findings of the current study showed that the incidence of stroke was significantly higher among patients aged 70 years or more, patients with history of stroke, patients with CHA2DS2VAS score of ≥ 4 for males or ≥ 5 for females, patients with hypertension and patients with diabetes. It is not surprising that the older people had high stroke risk because age is included in the calculation of CHA2DS2VAS score [13]. However, high risk is also attributed to the high prevalence of significant comorbidities including hypertension, diabetes, and heart failure, in the older population [13]. A study of 2163 patients, enrolled in the Jordan AF study, reported that patients aged ≥ 80 years old (17.5%) had higher prevalence of strokes (25.6% vs 14.7%, p < 0.001) and hypertension (79.9% vs 73.5%, p = 0.01), compared to patients younger than 80 years [13]. The older group had also higher mean CHA2DS2-VASc (5.0 ± 1.5 vs 3.6 ± 1.8, p < 0.001). The same study showed that anti coagulation therapy was mostly prescribed for elderly group [13]. Another Jordanian study reported that the strongest independent risk factors associated with stroke were past stroke history and high-risk CHA2DS2-VASc score [12]. Regarding hypertension, this condition often concurs with AF. It has been estimated that 60–80% of patients with AF have hypertension [22]. Hypertension contributes to various abnormal changes including hypertrophy of left ventricle, impairment of diastolic filling, increased pressure of left atrium, hypertrophy of left atrium, increased fibrosis of atrium, and slowing velocities of electrical conduction [23]. These changes increase the progression of atrial fibrillation and the risk of thromboembolic stroke [23]. A study reported that stroke incidence is three-fold higher in patients who have coexisting atrial fibrillation and hypertension [23].
The findings of the present study showed that only diabetes was significantly associated with increased odds of stroke after adjusting for age, past history of stroke, and CHA2DS2VAS score. Given diabetes is a key component of the CHA2DS2VASc risk score, the risk of stroke in patients with AF increases in the presence of diabetes [24]. This can be confirmed by the clinical practice guidelines which have indicated that most patients with coexisting diabetes need anticoagulation therapy since their risk of stroke is viewed to be high enough to counteract the risk of bleeding resulted from anticoagulation [17]. Diabetes mellitus increases the risk of thromboembolism through several abnormal alterations including endothelial dysfunction, increased hypercoagulability, and reduced fibrinolysis [25]. The Emerging Risk Factors Collaboration reported that patients with diabetes mellitus had adjusted hazard ratios of 2.27 and 1.56 for the risk of ischemic strokes and hemorrhagic strokes, respectively [25, 26].
Our study showed that the combination of metabolic abnormalities (hypertension, diabetes, and dyslipidemia) was significantly associated with increased odds of stroke. This result is in line with a finding of an 11-year study targeting 425 600 patients, of those 880 had AF. Overall, incidence of ischemic stroke was 1.11 in patients with AF and 0.35 in patients without AF (p < 0.001) [27]. The study concluded that the higher number of metabolic comorbidities increases the ischemic stroke incidence, and the association of AF with stroke can be eliminated with the combined impact of multiple metabolic comorbidities [27]. Thus, prevention of stroke should be focused on the combined impacts of multiple factors associated with stroke rather than on a particular factor such as atrial fibrillation [27]. Another study of 48 189 persons with AF and 3 076 355 persons without AF reported that the risk of ischemic stroke increases in the presence of multiple comorbidities [14]. Therefore, comprehensive AF care approach, including early detection, assessment, and management of concurrent metabolic abnormalities, is crucial to minimize the stroke risk and prevent serious health complications (1). Specifically, patients with coexisting atrial fibrillation, DM, and hypertension need particularly to have their blood pressure and blood glucose sufficiently controlled. Our study highlights the importance of patient education to improve management of patients living with AF and other associated abnormalities. Studies showed that patients education can also assist with improving adherence to take anticoagulation medication, follow dietary restrictions, and seek medication attention when needed, and ultimately reduce the risk of worsening worse cardiovascular prognosis [28, 29].
Our study has two main strengths. First, it is the first contemporary Middle Eastern study on atrial fibrillation. Most of the previous atrial fibrillation studies were conducted at least five to ten years ago. Second, the study is the first multi-center study conducted in the region to investigate warfarin population.
The limitation of the study includes that observational studies can cause potential bias. Despite the emphasis on consecutive enrollment, participants might not have been enrolled consecutively. In our study, all participants received AF management at health centers by cardiologists, while other patients in the country might be managed by their family medicine physicians, internists, or general physicians.