The burden of atrial fibrillation related to metabolic risks: different countries and territories, yet the same challenges

This editorial refers to ‘Global, regional, and national burden of atrial fibrillation/flutter related to metabolic risks over three decades: estimates from the Global Burden of disease Study 2019’, by Jiang et al. https://doi.org/10.1093/ehjqcco/qcae033. A broad range of risk factors have been demonstrated to be associated with incident atrial fibrillation (AF),1 among which metabolic disorders such as obesity, diabetes, and hyperlipidaemia are increasing rapidly in recent decades.2 However, socioeconomic, demography, and psychosocial factors vary significantly among different countries and territories, which not only influences the prevalence of metabolic risk factors and incidence of cardiovascular diseases (CVD) including AF, but also affects the outcome of these metabolic risk factors and CVD.3,4 Estimation of the burden of AF related to these metabolic risks may help decision-making of preventive strategies associated with both AF and the metabolic risks. In this issue of the journal, Jiang et al.5 used the Global Burden of Disease (GBD) study 2019 to assess epidemiological data and trends in AF/atrial flutter (AFL) burden related to metabolic risk factors. The metabolic risk factors investigated in GBD included high fasting plasma glucose, high low-density lipoprotein cholesterol, high systolic blood pressure, high body mass index, low bone mineral density, and kidney dysfunction. They evaluated the total number of deaths, age standardized rates (ASRs) deaths, disability-adjusted life years (DALYs), and estimated annual percentage change (EAPC) of metabolic risks related AF/AFL from 1990 to 2019. They show that from 1990 to 2019, the total number of deaths and DALYs of global metabolic risks related AF/AFL increased by 162.95% and 120.30%, respectively, although the overall EAPC of deaths and DALYs during the three decades was declining [−0.01 (−0.04–0.02) for deaths and −0.02 (−0.05–0.01) for DALYs, respectively]. The authors further explored the associations of sociodemographic index (SDI) with the deaths/DALYs rates of metabolic risks related AF/AFL and found an inverted V-shaped correlation between the two, that is, both low and high SDI regions were associated with lower deaths/DALYs rates, while middle SDI regions were associated with higher deaths/DALYs rates. However, in low SDI countries and territories, metabolic risks, compared with other risk factors, contributed most to deaths (40.77%), and DALYs (39.66%) in AF/AFL. The epidemiological data provide by this study address the impact of metabolic risk factors on the burden of AF/AFL, showing how trends of metabolic risks related AF/AFL burden varied in different SDI regions. Overall, the ASR deaths of CVD in high SDI regions has decreased when compared with 1990.6 Similarly, the overall trends of deaths/DALYs in metabolic risks related AF/AFL decreased over the past three decades although the absolute numbers were still high. This significant change is probably related to the proactive measures adopted by developed countries in healthcare policies, e.g. the National Cholesterol Education Program in the US,7 the Salt Intake Reduction Program in the UK,8 and the Sugar Reduction Program in the UK,9 etc. These governmental policies contributed significantly to the reduction in the metabolic risks related to CVD. In middle SDI regions, rapid increases of metabolic risks exceeded the socioeconomic and healthcare support, making the impact of the ‘metabolic risk’ burden even more prominent. CVD has been traditionally regarded as ‘diseases of affluence’ occurring more commonly in developed countries; however, with epidemiological transitions in ageing, unhealthy lifestyles, and socioeconomic changes take place, more developing regions enter into the ‘affluence’ ranks.10 Nevertheless, insufficient healthcare and preventive strategies in these developing regions cause rapid growth of various CVD, including AF. Indeed, the GBD database has shown that age-standardized CVD rates have begun to rise in many regions where they were previously declining.11 Hence, no matter what the SDI is, AF burden remains a common challenge, and controlling the metabolic risks should reduce both incident AF and its complications. Another important finding in the study by Jiang et al.5 is that females suffered a greater burden of deaths and DALYs compared with males, but it is perhaps worth noting that the trends of deaths and DALYs rates in female from 1990 to 2019 were generally decreasing [EAPCs −0.04 (−0.07, −0.02) for death and −0.07 (−0.1, −0.03) for DALYs, respectively], while the corresponding values were increased in males [EAPCs 0.16 (0.13, 0.19) for death and 0.04 (0, 0.09) for DALYs, respectively]. Indeed, the trends in females over the past three decades were showing improvement, compared with the deterioration seen in males. It also suggests controlling metabolic risks more aggressively will further mitigate the AF/AFL burden for both sexes, especially for males to slow down or reverse the increase. Nevertheless, in daily practice, various metabolic factors are polyphenotypic and their impact on AF outcomes are complex. For example, obesity is a common metabolic disorder, but obesity is not a binary (yes, no) diagnosis but includes metabolically healthy and unhealthy obesity.12 The prognosis of the two types of obesity in AF patients are different, with worse outcomes in metabolically unhealthy obesity.13 Therefore, the interaction among the metabolic disorders can be complicated, and their respective and combined effects on CVD need to be clarified. For metabolic risks, given that most of them are modifiable factors, the benefits are substantial once they are well controlled. Indeed, previous studies have demonstrated that smoking, diabetes, hyperlipidaemia, and hypertension account for more than 80% of the risk of coronary heart disease.14 Similarly, metabolic disorders such as hypertension, obesity, dyslipidaemia, impaired insulin tolerance, and other unhealthy lifestyles contribute significantly to incident AF.15,16 Conversely, weight loss, glycemic and blood pressure control, and other healthy lifestyle behaviours have been associated with marked reductions in the incidence and burden of AF and its complications.17,18 The advantage of using the GBD database lies in its global, regional, and national spatiotemporal data, which can be easily used for horizontal and/or longitudinal comparisons globally or within a certain regions or multi-regions. The epidemiological data and predictive models based on the spatiotemporal data provide prospective insights for the healthcare decision-making. In terms of AF, prevention and treatment are equally important. Faced with the heavy burden of AF, aggressive strategies should be taken from the government level to make the public realize the importance of controlling metabolic disorders, which is especially needed in regions with AF patients rapid-growing or low SDI regions since metabolic factors account for substantial numbers of deaths and DALYs in these low SDI regions. Education and publicity are helpful to the promotion of awareness of AF and its risk factors, while regular checkups could detect AF and/or its related risk factors including metabolic disorders at an earlier stage. To reduce the risks of AF onset, primary prevention strategies should be recommended to the general population, particularly those at high risk of AF, to receive comprehensive integrated lifestyle and risk factor modification, including maintenance of ideal weight, optimal blood pressure and glucose control, and other lifestyle changes recommended by current guidelines.19 Meanwhile, strategies should be developed for specific populations such as females, the elderly, or the young who are at high risk of AF due to their unique socioeconomic status. Currently, a holistic or integrated care approach based on the validated Atrial fibrillation Better Care (ABC) pathway includes anticoagulation/avoid stroke, better symptom management with rate or rhythm control, and cardiovascular risk factors and comorbidities optimization, is recommended.20 The benefit of adherence to ABC pathway in patients with AF has been shown in many studies.21–23 Meanwhile, it is estimated that implement of ABC pathway in patients with AF would result in substantial NHS healthcare cost reductions in the UK.24 In conclusion, metabolic abnormalities are risk factors for CVD but are modifiable. The global challenge of AF warrants health policies and cost-effective interventions to reduce the suffering of both metabolic risk factors and AF. Things can only get better. The authors declare no conflict of interest