Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in clinical practice.1,2 What was defined in the past as a simple arrhythmia characterized by irregularly irregular heartbeats is now accepted as a common and rapidly growing clinical problem and as a disease entity. Few previous studies have reported trends in the prevalence3–5 and medical management of AF in the last 10 years in a European country, specifically regarding oral anticoagulation, which should reflect the recommendations of the European guidelines.

Against this background, we sought to define trends in AF prevalence and its medical management based on data from two cross-sectional studies performed in a European country at an interval of 10 years (1999 and 2009).

The prevalence of AF increased by 27.9% between the two registries: from 4.8% (1540/32051) to 6.14% (1544/25137) (p<0.01). This increase was mainly in those aged over 70 (Figure 1). In both registries the proportion of women was higher in patients with AF. It is noteworthy that the prevalence of hypertension, diabetes, heart failure (HF), coronary artery disease (CAD), dyslipidemia, left ventricular hypertrophy (LVH) and previous stroke in AF patients also increased significantly between 1999 and 2009 (Table 1). Of the 10743 patients with hypertension, 55.4% (95% CI: 55.1–55.7%) had controlled blood pressure in the 2009 registry, compared with 40% (95% CI: 39.9–40.1%) in the 1999 CARDIOTENS study, a relative increase of 38.5% (p<0.01) in the rate of blood pressure control. On the other hand, the prevalence of current smokers was significantly lower in the later study (15.0%, 95% CI: 14.9–15.1 vs. 8.9%, 95%: CI: 8.8–8.9, p=0.01).

Figure 1.

Prevalence of atrial fibrillation by age-group in CARDIOTENS 1999 and CARDIOTENS 2009.

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Regarding medical treatment, changes in pharmacological management were identified (Table 2). Firstly, the prescription of antiplatelets increased from 31.0% to 38.2%; however, this increase was mainly observed in patients aged under 70, and in those aged over 70 the rate of antiplatelets decreased (Table 3A). Secondly, a significant increase (p<0.01) in the number of patients being treated with OAC was also identified: 33.0% (95% CI: 32.0–34.0%) vs. 62.7% (95% CI: 59.9–65.5%), a relative increase of 90%; this rise was more evident in patients aged over 70 (Table 3B).

We also analyzed trends in the use of oral anticoagulants according to age and medical specialty. As shown in Figure 2, in the 1999 registry a decrease in oral anticoagulation was observed with increasing age; nevertheless, the reverse tendency was seen in 2009, with a trend for increased prescription of oral anticoagulation in older patients. The use of oral anticoagulation was greater in all age-groups in 2009 compared to 1999 (p=0.01). Furthermore, whereas in 1999 there were significant differences in the rate of oral anticoagulation depending on whether they were seen by primary care physicians or cardiologists, this difference disappeared in 2009.

Figure 2.

Trends in the use of oral anticoagulants according to age-group and medical specialty in the two studies.

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The use of other treatments in patients with AF rose significantly between the two periods surveyed: prescription of angiotensin-converting enzyme inhibitors (ACEIs), angiotensin-receptor blockers (ARBs), calcium channel blockers (CCBs), nitrates and beta-blockers was higher in the 2009 study.

Over the course of the study period, an increase in the prevalence of AF was observed, mainly due to a higher prevalence of AF in patients aged over 70, as well as more aggressive antithrombotic treatment and radical changes in the use of oral anticoagulants, reversing the decrease in their use in elderly patients seen in the first registry. Comparison of the two registries thus revealed significant shifts in the perception and treatment of patients with AF.

One possible explanation for the increase in AF prevalence is that it results from ascertainment bias related to the increased use of electrocardiography in the community. However, this was addressed and found to be an unlikely cause in the Rochester population,11 since over a 30-year period, the use of electrocardiograms increased only from 9% to 12%, as opposed to the two- to threefold increase in the prevalence of AF. Another hypothesis is that today's elderly are a sicker population: advances in preventive medicine and increasing socioeconomic prosperity have resulted in a population of elderly survivors with a higher prevalence of comorbidities including hypertension, diabetes, HF, CAD and prior cardiac surgery, in comparison with their counterparts who lived to a similar age 50 years ago.12,13 Nonetheless, when these risk factors are put into context with the size of the increase in AF prevalence, the relatively small increase in the prevalence of known comorbidities does not appear to offer more than a partial explanation.14 Therefore, these epidemiological studies need to be complemented with further analysis aimed at defining the molecular genetics of AF, in order to provide more insights into the structural and electrical phenotypes resulting from genetic mutations and their interactions with the environment. Otherwise, there is a danger that the burden of this disease could reach epidemic proportions in coming years.3

On the other hand, physicians should be aware that they are facing more complex patients, since the elderly have not only the highest risk of stroke among patients with AF, but also the highest risk of bleeding. Moreover, the present AF population exhibits a higher risk for thromboembolic events, due to the higher prevalence of hypertension, diabetes, previous stroke and HF. These epidemiological features indicate a need for new therapeutic strategies, including new oral anticoagulant agents (oral direct thrombin inhibitors such as dabigatran etexilate and AZD0837, and oral factor Xa inhibitors such as rivaroxaban, apixaban, edoxaban, betrixaban and YM150). These agents, with a safer drug profile, may provide a useful alternative to current vitamin K antagonists. Another factor increasing the need for safer agents is the wider indications for oral anticoagulation therapies in the current clinical guidelines for patients with AF.15,16 A recent analysis of the 2009 CARDIOTENS study reported that the current guidelines have increased candidates for OAC by 25%.6 This could be the reason for the significant increase in the rate of OAC prescription compared to 1999, especially in patients aged over 70. This increase could explain the decrease in the use of antiplatelets seen in patients aged over 70. Studies published in the last decade have shown that both aspirin monotherapy and dual antiplatelet therapy with clopidogrel are less effective than OAC and furthermore are associated with higher rates of bleeding.17,18 It is therefore encouraging that the awareness of physicians (both general practitioners and cardiologists) of the appropriate use of antithrombotic drug therapy in AF and of the results of recent clinical trials has improved over the last decade, to the extent that there are now no differences in the rate of OAC prescription according to the attending physician, as was the case in previous studies.19,20

It is noteworthy that the prevalence of hypertension in patients with AF also increased in the last decade. On the other hand, there has been progress in the rate of hypertension control (relative increase of 38.5%). This is important because of the emphasis on upstream therapies to slow or halt the progression of AF due to underlying cardiovascular disease and to AF itself. Such agents include ACEIs, ARBs, statins, n-3 (omega-3) polyunsaturated fatty acids, and possibly corticosteroids.15 As seen in this study, the recommendations reflect the evolution of medical therapeutics in the last 10 years, with a significant increase in the prescription rate of beta-blockers, ACEIs/ARBs and statins. Significant changes were also observed in the choice of ventricular rate control agents throughout the study period. In the 1990s, digoxin was the preferred agent for controlling ventricular rate, but during the study period the use of beta-blockers and CCBs increased significantly, due in part to the growing recognition that digoxin is particularly ineffective at controlling ventricular rate with effort.21 This is also likely to be related to the publication during this period of studies demonstrating the effectiveness of beta-blockers in patients with HF.22 To summarize, this comparative analysis of these two large observational, cross-sectional cohort studies has revealed long-term trends in the prevalence and clinical and pharmacological management of patients with AF. Mean age, prevalence of risk factors, and prevalence of AF were similar to those in previous national and international studies, reflecting standard clinical activity.23–27

Some limitations must be acknowledged, including those inherent to observational studies, which provide insufficient evidence to establish causal relationships. The fact that most patients were included by primary care physicians may mean that they are not representative of other areas of medicine. Another important limitation is that the investigators were not selected randomly from all physicians nationwide, but by randomly inviting those registered in community listings. Physicians participating in the study may therefore have been more motivated and more aware of the importance of these studies.

AF prevalence has increased over the last decade. This increase is due to the higher prevalence of AF in people over 70 years old. Moreover, the current AF population exhibits a higher risk profile for thromboembolic events because of the higher prevalence of hypertension, diabetes, CAD, LVH, previous stroke and HF. Regarding medical treatment, firstly more aggressive antithrombotic treatment has been observed, as well as radical changes in the use of oral anticoagulants, reversing the decreasing use in elderly patients observed in 1999. Furthermore, there are no longer differences in the rate of OAC prescription according to the attending physician (general practitioner or cardiologist). Secondly, there has also been considerable emphasis on upstream therapies in the general population with AF.

The study presented here was funded by an unrestricted educational grant from Recordati Spain S.A. and was endorsed by the Hypertension Section and the Research Agency of the Spanish Society of Cardiology. Dr. Rodríguez-Mañero received a post-residency grant for international research from the European Heart Rhythm Association (EHRA Training Fellowship Program).

The authors have no conflicts of interest to declare.