Atrial fibrillation (AF) is the most common arrhythmia in diabetics, with the percentage of diabetics developing AF ranging from 5.2–47.1%10. The notably high percentage (50.36%) of AF in our diabetic population is concerning. It is well-known that diabetes mellitus (DM) is an independent factor for developing AF, with a prevalence twice as high compared to those without DM2, 11, 12. The mechanisms involved in AF development in DM include three interrelated phenomena generated by DM: inflammation, oxidative stress, and glycemic fluctuations. These lead to myocardial remodeling (atrial, in this case) at three levels: electrical (conduction abnormalities), structural (dilation and fibrosis), and autonomic (autonomic imbalance)11, 12. Therefore, proper screening in diabetic patients is essential to detect silent or mildly symptomatic AF for timely management and prevention of cardiovascular events, particularly ischemic stroke.
It was found that, for each additional year gained, the frequency of AF presentation in patients with DM decreased by 3% (ORa: 0.97; 95% CI: 0.968–0.987; p < 0.001). This may seem contradictory, but it has been reported that developing DM at a younger age increases the risk of AF [2]. DM poses a higher risk of AF in younger patients, regardless of DM control, unlike the general population where the risk of developing AF increases with age2, 8.
Gender can also influence the risk of AF in diabetic patients. Studies have found that men have a higher risk of developing AF than women13, 14. Despite this, no significant association was found in this study. In a cohort study with similar objectives, similar incidence rates of AF were found between men and women with type 2 diabetes compared to controls (rates of 1.34 and 1.35, respectively)15. This suggests that, overall, gender alone does not seem to be a primary risk factor for AF in patients with type 2 diabetes. However, differences in the absolute and relative risk of AF are observed when stratified by age. In men, the absolute risk of AF was higher than in women, but the relative risk was higher in women with type 2 diabetes compared to their respective matched controls. This could indicate that age and other factors related to type 2 diabetes may influence the association between gender and AF.
Excessive alcohol consumption is a risk factor for AF in the general population, and in patients with DM, it is even more critical, as demonstrated by this study (ORa: 1.44; 95% CI: 1.132–1.835; p = 0.003). The amount of alcohol consumed is directly related to the increased risk of AF, pointing to a dose-dependent relationship [16, 17]. Alcohol plays a significant role in generating AF through various mechanisms, such as altering the electrical properties of the atria, characterized by shortening of refractoriness, slowing conduction velocity, and increasing ectopic beats. It also induces changes in the structure and function of atrial cardiomyocytes, leading to fibrosis, and autonomic imbalance [18, 19, 20, 21]. All of this, combined with myocardial inflammation and fibrosis, which can be caused by DM [known as diabetic cardiomyopathy], further increases the likelihood of developing AF [11, 12, 22].
Additionally, alcohol is a factor in the development of other comorbidities leading to AF, such as obesity, sleep apnea, and arterial hypertension [17, 22, 23], increasing the risk of cardiovascular events. Furthermore, in patients with AF requiring chronic anticoagulation, alcohol increases the risk of bleeding (part of the HASBLED score) [2].
Elevated levels of glycated hemoglobin have been significantly associated with a lower risk of developing AF; a finding that may seem contradictory initially. However, it is essential to consider that there is an established linear relationship between the risk of AF and the duration of DM, especially when the latter exceeds 20 years, as well as with glycemic control [24, 25]. In this context, it is suggested that, despite the apparent lack of control in the analyzed population, some individuals may be in an early stage of disease decompensation, which could explain the absence of a significant increase in the risk of AF in this group.
It is worth mentioning that the time since the diagnosis of DM in patients was not taken into account in the analysis. Recently diagnosed patients may be in a stage of metabolic compensation, while those who have lived with DM for a more extended period may be better controlled. Additionally, it has been observed that some patients with late complications of DM, such as peripheral arterial disease (PAD), chronic kidney disease (CKD), or cerebrovascular disease (CVD), may already present AF. In these cases, intensive DM treatment is applied to prevent additional complications, reduce mortality, and decrease the risk of AF [9, 23].
It is relevant to note that certain DM medications, such as metformin, can decrease the risk of developing AF, while others, such as sodium-glucose cotransporter-2 inhibitors (SGLT2i), have also shown benefits in this regard. In the DECLARE-TIMI 58 study, the impact of dapagliflozin, an SGLT2i, was evaluated in patients with type 2 diabetes mellitus. The results revealed that dapagliflozin reduced the risk of AF and atrial flutter by 19%, both in patients with a history of AF/aflutter and those without these antecedents. This reduction remained consistent regardless of the presence of atherosclerotic cardiovascular disease or heart failure. It is suggested that the benefits could be related to the promotion of natriuresis and diuresis, as well as other positive cardiovascular effects of SGLT2i, implying the possibility that dapagliflozin offers additional benefits by reducing the risk of AF/aflutter events in patients with type 2 DM [12, 22, 26]. However, it is essential to note that the medications provided by the systems of medical insurance in Peru are usually conventional. Although they can reduce blood glucose levels [even with a higher risk of hypoglycemia], they may not reduce the frequency of AF in the same way as more recent and specific medications.
The limitations of the study were related to the existence of inclusion bias, which was avoided by selecting the largest hospital in the city and including all consecutive patients who met the selection criteria.