Physicians' Academy for Cardiovascular Education

Type 2 diabetes, glucose homeostasis and incident atrial fibrillation: ARIC study

Literature - Huxley r et al; Heart. 2012 Jan;98(2):133-8.

Type 2 diabetes, glucose homeostasis and incident atrial fibrillation: the Atherosclerosis Risk in Communities study.


Huxley RR, Alonso A, Lopez FL, Filion KB, Agarwal SK, Loehr LR, Soliman EZ, Pankow JS, Selvin E.

Heart. 2012 Jan;98(2):133-8.

Type 2 diabetes has been inconsistently associated with the risk of atrial fibrillation (AF) in previous studies that have frequently been beset by methodological challenges.

 

Design: Prospective cohort study.
Setting: The Atherosclerosis Risk in Communities (ARIC) study.
Participants: Detailed medical histories were obtained from 13 025 participants. Individuals were categorised as having no diabetes, pre-diabetes or diabetes based on the 2010 American Diabetes Association criteria at study baseline (1990-2).
Main outcomes measures: Diagnoses of incident AF were obtained to the end of 2007. Associations between type 2 diabetes and markers of glucose homeostasis and the incidence of AF were estimated using Cox proportional hazards models after adjusting for possible confounders.
Results: Type 2 diabetes was associated with a significant increase in the risk of AF (HR 1.35, 95% CI 1.14 to 1.60) after adjustment for confounders. There was no indication that individuals with pre-diabetes or those with undiagnosed diabetes were at increased risk of AF compared with those without diabetes. A positive linear association was observed between HbA1c and the risk of AF in those with and without diabetes (HR 1.13, 95% CI 1.07 to 1.20) and HR 1.05, 95% CI 0.96 to 1.15 per 1% point increase, respectively). There was no association between fasting glucose or insulin in those without diabetes, but a significant association with fasting glucose was found in those with the condition. The results were similar in white subjects and African-Americans.
Conclusions: Diabetes, HbA1c level and poor glycaemic control are independently associated with an increased risk of AF, but the underlying mechanisms governing the relationship are unknown and warrant further investigation.
 

Background

In some studies, type 2 diabetes was reported to be associated with an increased risk of AF [1-3]. The relationships between markers of glucose homeostasis and AF have not been widely studied.In the Atherosclerosis Risk in Communuties study (ARIC) this association was studied in a population of white subjects and African-Americans.

Main results

Individuals with diabetes had a greater risk of incident AF compared with those without (HR 1.35; 95% CI 1.14-1.60, fig. 1). Individuals with pre-diabetes or undiagnosed diabetes were not increased risk compared with those without diabetes
There was a positive linear relationship between HbA1c and the risk of AF in individuals with and without diabetes (HR 1.13, 95%CI 1.07-1.20, p<0.001) and HR 1.05, 95% CI 0.96-1.15, p=0.07 per 1% point increase, respectively).
In patients with diabetes, there was a significant association with fasting glucose, but not in those without. No association was found between fasting insulin and risk of incident AF. In white subjects and African-Americans there were no differences in results.

Conclusion

Patients with diagnosed diabetes have a higher risk of AF. Underlying mechanisms are still unclear; the impact of diabetes on the risk of AF seem to develop only after a prolonged exposure to diabetes.



References

1. Finn Go AS, Hylek EM, Phillips KA, et al. Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the AnTicoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study. JAMA 2001;285:2370e5.
2. Huxley R, Barzi F, Woodward M. Excess risk of fatal coronary heart disease associated with diabetes in men and women: meta-analysis of 37 prospective cohort studies. BMJ 2006;332:73e8.
3. Frost L, Hune LJ, Vestergaard P. Overweight and obesity as risk factors for atrial fibrillation or flutter: the Danish diet, cancer, and health study. Am J Med 2005;118:489e95.

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