AF in Population With Impaired Glucose Tolerance
AF in Population With Impaired Glucose Tolerance
Background The role of dysglycemia as an additional risk factor for atrial fibrillation (AF) is controversial. Therefore, it was of interest to assess risk factors for incident AF in a large, representative population of patients with cardiovascular risk factors and impaired glucose tolerance but not overt diabetes in NAVIGATOR.
Methods Predictors of incident AF were analyzed in 8,943 patients without AF at baseline by Cox proportional hazards regression. Study treatments (valsartan vs no valsartan and nateglinide vs no nateglinide) and the time-dependent covariate for progression to type 2 diabetes mellitus were added separately to the model.
Results The median age of the 8,943 patients included in the present analysis of the NAVIGATOR trial was 63 years. Half of those patients were men, 6,922 (77.4%) had a history of hypertension, and 255 (2.9%) had heart failure. The median glycated hemoglobin was 6%. During the study, 613 of the 8,943 patients without AF at baseline presented with at least 1 episode of AF (6.9% 5-year incidence). Besides established predictors of incident AF, a 1 mmol/L increment of baseline fasting glucose, but not progression to diabetes, was found to be associated with a 33% increased risk of incident AF. Neither valsartan nor nateglinide affected AF incidence.
Conclusions In a trial population with impaired glucose tolerance, fasting plasma glucose and well-known risk factors (age, hypertension, and elevated body weight), but not progression to diabetes, predict risk of AF.
Atrial fibrillation (AF) is the most common chronic arrhythmia and is likely to increase in prevalence because of aging of the population. Atrial fibrillation worsens quality of life and increases the risk of stroke, heart failure, and death. Restoration of sinus rhythm is difficult because AF is, in most instances, associated to remodelling of atrial electric and mechanical properties, which perpetuates the arrhythmia. Prevention of AF may be the preferable strategy, but prevention depends on identifying and correcting risk factors that favor the onset of AF.
The Framingham Heart Study showed that age, male sex, body mass index, hypertension, heart failure, and valvular diseases were independent risk factors for AF. This study's findings allowed for the creation of a risk score. The role of dysglycemia as an additional risk factor for AF is controversial. A recent meta-analysis showed that diabetes is a significant risk factor for AF (relative risk compared with no diabetes 1.24), but the population fraction of AF attributable to type 2 diabetes mellitus was only 2.5%. The Women's Health Study also showed a statistically significant relation between type 2 diabetes mellitus and AF, but the investigators suggested that this association may be driven by other risk factors, such as obesity and arterial hypertension. Watanabe et al reported in a Japanese population that impaired fasting glucose was related to a higher risk (hazard ratio [HR] 1.35) of AF. Insulin resistance rather than hyperglycemia per se may be a determinant of AF in these patients.
A recent analysis of 9,306 patients enrolled in the NAVIGATOR trial showed that AF at study entry was an independent predictor of cardiovascular events over 6.5 years of follow-up. Therefore, it was of interest to assess risk factors for incident AF in a large, representative population of patients with cardiovascular risk factors and impaired glucose tolerance (IGT) but not overt diabetes, such as those enrolled in NAVIGATOR. A distinctive feature of this population was that 35% of patients developed diabetes, thus allowing us to also assess the impact of this time-dependent variable on new occurrence of AF.
Abstract and Introduction
Abstract
Background The role of dysglycemia as an additional risk factor for atrial fibrillation (AF) is controversial. Therefore, it was of interest to assess risk factors for incident AF in a large, representative population of patients with cardiovascular risk factors and impaired glucose tolerance but not overt diabetes in NAVIGATOR.
Methods Predictors of incident AF were analyzed in 8,943 patients without AF at baseline by Cox proportional hazards regression. Study treatments (valsartan vs no valsartan and nateglinide vs no nateglinide) and the time-dependent covariate for progression to type 2 diabetes mellitus were added separately to the model.
Results The median age of the 8,943 patients included in the present analysis of the NAVIGATOR trial was 63 years. Half of those patients were men, 6,922 (77.4%) had a history of hypertension, and 255 (2.9%) had heart failure. The median glycated hemoglobin was 6%. During the study, 613 of the 8,943 patients without AF at baseline presented with at least 1 episode of AF (6.9% 5-year incidence). Besides established predictors of incident AF, a 1 mmol/L increment of baseline fasting glucose, but not progression to diabetes, was found to be associated with a 33% increased risk of incident AF. Neither valsartan nor nateglinide affected AF incidence.
Conclusions In a trial population with impaired glucose tolerance, fasting plasma glucose and well-known risk factors (age, hypertension, and elevated body weight), but not progression to diabetes, predict risk of AF.
Introduction
Atrial fibrillation (AF) is the most common chronic arrhythmia and is likely to increase in prevalence because of aging of the population. Atrial fibrillation worsens quality of life and increases the risk of stroke, heart failure, and death. Restoration of sinus rhythm is difficult because AF is, in most instances, associated to remodelling of atrial electric and mechanical properties, which perpetuates the arrhythmia. Prevention of AF may be the preferable strategy, but prevention depends on identifying and correcting risk factors that favor the onset of AF.
The Framingham Heart Study showed that age, male sex, body mass index, hypertension, heart failure, and valvular diseases were independent risk factors for AF. This study's findings allowed for the creation of a risk score. The role of dysglycemia as an additional risk factor for AF is controversial. A recent meta-analysis showed that diabetes is a significant risk factor for AF (relative risk compared with no diabetes 1.24), but the population fraction of AF attributable to type 2 diabetes mellitus was only 2.5%. The Women's Health Study also showed a statistically significant relation between type 2 diabetes mellitus and AF, but the investigators suggested that this association may be driven by other risk factors, such as obesity and arterial hypertension. Watanabe et al reported in a Japanese population that impaired fasting glucose was related to a higher risk (hazard ratio [HR] 1.35) of AF. Insulin resistance rather than hyperglycemia per se may be a determinant of AF in these patients.
A recent analysis of 9,306 patients enrolled in the NAVIGATOR trial showed that AF at study entry was an independent predictor of cardiovascular events over 6.5 years of follow-up. Therefore, it was of interest to assess risk factors for incident AF in a large, representative population of patients with cardiovascular risk factors and impaired glucose tolerance (IGT) but not overt diabetes, such as those enrolled in NAVIGATOR. A distinctive feature of this population was that 35% of patients developed diabetes, thus allowing us to also assess the impact of this time-dependent variable on new occurrence of AF.
