This study aimed to assess the prevalence and associated factors of AF among adult cardiac patients at follow-up at the Adama Hospital Medical College. Our findings revealed that the prevalence of atrial fibrillation (AF) among adult cardiac patients was 19.6%. Similarly, our findings were in line with the findings of studies conducted in Sub-Saharan Africa, which reported rates ranging between 4.6% and 20.8% [16]. However, this finding was higher than the prevalence of 1–2% found in the general population [17]. These findings suggest that cardiac patients are at a higher risk of developing AF than the general population, which is consistent with expectations given their underlying cardiac conditions.
In this study, sociodemographic and behavioral factors were associated with atrial fibrillation. We found that compared with female sex, male sex was significantly associated with a greater risk of developing atrial fibrillation. This result was in line with the findings of a study conducted in Ethiopia [16], which revealed that males have a greater risk of atrial fibrillation (AF) due to various factors. This may include biological differences, lifestyle factors, and discrepancies in healthcare-seeking behavior. Similarly, the study revealed that individuals who chewed khat were a fourfold greater risk of atrial fibrillation (AF) than non-chewers. The observed association might be explained by the effects of khat increasing the risk of cardiovascular-related disease, including increased heart rate, blood pressure, and sympathetic activity [18]. Khat has the potential to worsen pre-existing cardiac conditions [19, 20]. Furthermore, our study identified alcohol consumption as a risk factor for atrial fibrillation (AF) among cardiac patients. This finding was in line with the findings of a cohort study conducted in Norway [21]. Further investigation into the specific mechanisms and dose-response relationships between alcohol consumption and AF is crucial for developing personalized risk assessment and prevention strategies.
This study revealed that valvular heart disease (VHD) is significantly associated with atrial fibrillation (AF). This finding was consistent with the previous findings [22, 23]. This may be due to heart valve abnormalities in VHD causing fibrosis and scarring, affecting valve function and creating arrhythmogenic substrates in the atria, increasing susceptibility to arrhythmia [24]. Moreover, VHD disrupts heart chamber blood flow, promoting stasis and thrombus formation, which can embolize the systemic circulation, potentially leading to stroke or other thromboembolic events [25]. Similarly, we found that patients with cardiomyopathy had a significant association with atrial fibrillation (AF). The risk of developing AF among patients who had cardiomyopathy was nearly two times greater than that of patients without this condition. To date, there is no literature available on the relationship between AF and cardiomyopathy. Therefore, further research involving a larger, multicenter cohort is required to gain a comprehensive understanding of these factors.
Accordingly, our study revealed a robust association between a history of stroke and a relative risk of atrial fibrillation (AF). Patients with a previous history of stroke faced nearly triple the risk of experiencing AF compared to their counterparts. This finding agreed with prior research indicating a substantial increase in AF likelihood among individuals with a history of stroke [3]. Evidence shows that approximately 20–30% of stroke patients are diagnosed with AF before their cerebrovascular incident, while up to 24% of stroke patients may experience AF solely through intensive cardiac monitoring [26]. This may be due to the bidirectional nature of the association between AF and stroke. Common underlying risk factors for AF and stroke include hypertension, diabetes, obesity, and advanced age, which contribute to their development and can exacerbate their interrelationship [27]. Moreover, changes in the autonomic nervous system resulting from stroke may create conditions favorable to cardiac arrhythmias, particularly atrial fibrillation, via mechanisms such as autonomic dysregulation. [28].
We found that chronic kidney disease (CKD) was significantly associated with atrial fibrillation among cardiac patients. Patients with CKD had a nearly threefold greater risk of developing atrial fibrillation than patients without CKD. These findings were supported by a previous study conducted in Japan [29]. This can be explained through several physiological mechanisms. First, CKD often leads to fluid and electrolyte imbalances, including potassium and magnesium imbalances, which can disrupt heart electrical activity, increasing the risk of developing atrial fibrillation [30, 31]. Second, CKD is linked to inflammation and oxidative stress, which can damage the heart's structure and function, potentially leading to the development of atrial fibrillation [32]. Third, CKD activates the renin-angiotensin-aldosterone system (RAAS), promoting cardiac remodeling, fibrosis, and atrial enlargement, and predisposing individuals to atrial fibrillation [33].
This study revealed that among patients, those with ischemic heart disease (IHD) had a lower risk of atrial fibrillation. Our findings contradict previous study findings [34–36]. The complex interplay between AF and IHD has been acknowledged [35]. The potential explanations for this finding include undiagnosed AF patients within the IHD group, survivor bias, variations in IHD severity, and differences in treatment strategies. Further research is necessary to elucidate the intricate relationship between IHD and AF.
While previous studies have established hypertension and diabetes mellitus (DM) as risk factors for AF, this study did not find statistically significant associations with these comorbidities. This discrepancy might be attributed to the relatively small sample size or the specific characteristics of the study cohort. Further research with larger sample sizes and longitudinal designs is needed to clarify the relationship between these comorbidities and AF in the Ethiopian context.
The limitation of the study
There are several limitations in this study. First, due to the absence of advanced diagnostic tools such as Holter and event monitors in the study area, the diagnosis of atrial fibrillation was based solely on traditional 12-lead ECG criteria. Second, this study is a single-center study, which may limit the applicability of the results beyond a specific hospital setting, potentially limiting their representativeness to the broader Ethiopian population. Third, this study included a relatively small sample size, which may lightly affect the precision level of estimation. Finally, the cross-sectional study design precludes establishing causal relationships between risk factors and atrial fibrillation (AF). Additionally, data on certain factors such as weight, height, and lifestyle habits were not consistently recorded for all patients. This lack of uniformity in data recording may result in inaccuracies in assessing both exposure and risk factors.