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High Risk and Mortality in Patients With Atrial Fibrillation and Diabetes

Apr 21, 2018
 

Risk for stroke significantly increased, but exceeded by heart failure

The purpose of the study was to describe complication patterns in patients with atrial fibrillation and diabetes mellitus.

 

326,832 patients in Sweden with non-valvular atrial fibrillation during 2006–2012 were identified, and information on events, comorbidities and pharmacological therapy was extracted using nationwide mandatory registers. Patients were followed until the end of December 2013 and the mean follow-up time was 3.7 years (0.9–8 years).

Diabetes was present in 17.7%. The most frequent events in those with and without diabetes were mortality (48.8% vs 36.4%; p < 0.001), heart failure (21.4% vs 13.1%; p < 0.001), ischemic stroke (8.2% vs 6.8%; p < 0.001), myocardial infarction (7.3% vs 4.3%; p < 0.001) and any bleeding (6.3% vs 5.2%; p < 0.001), respectively. Diabetes predicted mortality, combined event (first of mortality, heart failure, ischemic stroke or myocardial infarction), single events and bleeding. The standardized mortality ratio for patients with atrial fibrillation and diabetes compared to the general population was 2.06 (95% confidence level) and for patients with atrial fibrillation without diabetes was 1.33 (95% confidence level).

Globally, cardiovascular disease is the main contributor to mortality, accounting for about 17.5 million deaths, or 46.2% of deaths from non-communicable diseases. Atrial fibrillation (AF) is present in approximately 3% of the general adult population and the prevalence is expected to rise, mainly due to the ageing population.

Diabetes mellitus is a well-established risk factor for AF, increasing the risk for AFib by 40%. Even in patients with increased fasting glucose or metabolic syndrome, the AFib risk is increased by a similar magnitude. Retrospective data have shown a 70%–90% increase in the risk of stroke in those with coexisting diabetes and AFib compared to those with AF alone. In the CHA2DS2-VASc risk score system for calculating the risk for stroke in patients with AF, the presence of diabetes adds one point. Updated information on the risk for complications associated with diabetes in AF is important for determining future preventive strategies and for planning of healthcare resources.

The results showed that among 326,832 individuals with non-valvular AF, 17.7% (n = 57,953) had diabetes. Of those with diabetes, 28.9% had no Glucose Lowering Therapy ( GLT), 35.4% were treated with oral antiglycemic drugs (OAD) alone, and 35.7% were treated with insulin (with or without OAD). Patients with diabetes were slightly older, were more often male, and scored higher on the stroke risk scheme CHA2DS2-VASc.

Diabetes individuals more frequently had comorbidities such as hypertension, ischemic heart disease, stroke, heart failure, previous coronary revascularization, peripheral artery disease or chronic kidney disease. Accordingly, cardiovascular drugs were used more frequently in those with diabetes. The same risk factor burden and treatment patterns were seen at ages below 65 years, apart from the fact that male gender was more prevalent and alcohol consumption was more common in the diabetes group.  Anticoagulants (warfarin or newer oral anticoagulants) were more commonly used in those with diabetes. The proportion of diabetes patients with a CHA2DS2-VASc score of ⩾2 was 99% (n = 57,278). Among these, 53% were not treated with anticoagulants and 13% had neither anticoagulants nor antiplatelet agents. In general, diabetes individuals treated with insulin had a higher cardiovascular risk burden, and higher CHA2DS2-VASc and HAS-BLED scores. The mean follow-up time was 3.7 years (range = 0.9–8 years).

The most frequent event was mortality (48.8% vs 36.4%; p < 0.001), followed by heart failure (21.4% vs 13.1%; p < 0.001), ischemic stroke (8.2% vs 6.8%; p < 0.001), myocardial infarction (7.3% vs 4.3%; p < 0.001) and any bleeding (6.3% vs 5.2%; p < 0.001) in those with and without diabetes, respectively. Within the diabetes group, all events except bleeding occurred more frequently in those treated with insulin. The same pattern was also seen at ages below 65 years and in patients without previous AF at baseline, that is, with a first occurrence of AF. After adjustment for comorbidities, socioeconomic factors and medication, diabetes was independently associated with an increased mortality risk (HR = 1.28; 95% CI = 1.25–1.31) which was even more pronounced at ages below 65 years (HR = 1.59; 95% CI = 1.43–1.77).

From the results, it was concluded that patients with AF and diabetes have a high overall cardiovascular risk, with rates of mortality and heart failure exceeding those for stroke. This underlines that other preventive treatment strategies, beyond preventing stroke with anticoagulants, need to be implemented and further explored.

Practice Pearls:

  • For those with AFib and diabetes, there is a five-fold increased risk of stroke and two-fold increased risk of mortality.
  • The most frequent event was mortality by 48.8% for those with diabetes and AFib.
  • Patients with atrial fibrillation and diabetes have a high cardiovascular risk, with mortality and heart failure rates exceeding those for stroke.

References:

World Health Organization(WHO). Global status report on noncommunicable diseases 2014. Geneva: World Health Organization, 2015.

Kirchhof P, Benussi S, Kotecha D, et al. 2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS. Eur Heart J 2016; 37: 2893–2962.

Zoni-Berisso M, Lercari F, Carazza T,et al. Epidemiology of atrial fibrillation: European perspective. Clin Epidemiol 2014; 6: 213–220.