Prevalence of abnormal glucose metabolism in atrial fibrillation: A case control study in 75-year old subjects

Background: The prevalence of atrial fibrillation (AF) is increasing world wide and amongst factors that aggravate the risk is diabetes mellitus (DM), also in epidemic development. However, although DM is a potentially modifiable risk factor for AF, few, if any, studies have explored the prevalence of undiagnosed dysglycaemia among subjects with AF or if duration of AF are related to parameters of glycaemia or dysglycaemia prevalence. Methods: In this case control study, amongst 75-year old subjects with and without AF, the prevalence of dysglycaemia, i.e., impaired fasting glycaemia, impaired glucose tolerance or DM, according to World Health Organisation criteria was assessed by a 75-g oral glucose tolerance test (OGTT). Results: Prevalence of undiagnosed DM among the 108 subjects (male/female 73/35, BMI 25.4 +/- 3.2) without and the 46 (male/female 34/12, BMI 25.3 +/- 3.7) with AF (median AF duration five years) where 3.7% and 13.0%, respectively (p = 0.031, Odds ratio (OR) 3.86 (95% Confidence interval [CI]: 1.01, 16.25)) whereas the overall prevalence of dysglycaemia (prediabetes and DM) where similar (respectively 43.5% and 39.1%, p = 0.46, OR 0.83 [95% CI: 0.41, 1.69]). Patients with AF duration = 5 years had however a higher dysglycaemia prevalence (61.1% [DM 22.2%, prediabetes 38.9%]) as compared to AF duration < 5 years (25% [DM 7.1%, prediabetes 17.9%], p = 0.0014, OR 4.7 [95% CI: 1.30, 16.90]) or no AF (p = 0.17, OR 2.04 [95% CI: 0.73, 5.66]). There was also a significant correlation between the duration of AF and HbA1c (r = 0.408, p = 0.005) and fasting glucose levels (r = 0.353, p = 0.016). Conclusion: AF is associated with chronic hyperglycaemia amongst 75-year old subjects. Prediabetes and DM should be pro-actively assessed if AF duration >= 5 years.