Drinking more than 10 alcohol units
per week increases the risk of atrial fibrillation in persons with hypertensive
heart disease
The Losartan Intervention For Endpoint reduction in Hypertension
(LIFE) study shows that high intake of alcohol is associated with an increased
risk of new-onset atrial fibrillation (AF) in hypertensive patients with left
ventricular hypertrophy, measured by electrocardiography (ECG).
Binge drinking can induce atrial fibrillation. Long-term
moderate alcohol consumption appears not to increase the risk of new-onset AF;
a threshold effect has, however, been suggested with a significantly increased
risk of AF among the heaviest drinkers with an alcohol intake of more than 28-35
drinks per week.
People with atrial fibrillation (AF) have increased risk
of hospitalization or death due to stroke, myocardial infarction or heart failure.
The incidence of new-onset AF is increased in persons with hypertension and even
more if left ventricular hypertrophy has developed. Medical treatment of hypertension
reduces new-onset AF and treatment with the angiotensin receptor blocker losartan
is more effective than the beta-1 selective blocker atenolol in this respect.
However, it is unclear how smoking and alcohol intake influence the risk of new
AF during antihypertensive treatment.
In LIFE, a double-blinded, randomized, parallel-group
study, 9,193 hypertensive patients (46% men; mean age 67 years, mean blood pressure
174/98 mmHg) with ECG-documented left ventricular hypertrophy, received either
losartan- or atenolol-based blood pressure lowering therapy, and were followed
for a mean time of 4.8 years. The study was funded by Merck & Co and took
place in Scandinavia, the United Kingdom and the United States in 1995-2001. At
baseline 8,831 patients neither had a history of AF nor AF by ECG, and were thus
at risk of developing this condition during the study.
ECG confirmed new-onset AF in 353 patients. This occurred
in 5.7% of patients with baseline alcohol intake above 10 units per week (n =
20) versus 3.9% patients with lower or no alcohol intake (n = 333). Intake of
alcohol above 10 units per week increased the risk for new-onset AF in univariate
Cox regression analysis, with hazard ratio (HR) (95% CI) 1.6 (1.0, 2.5) p=0.042.
In multivariate Cox regression, intake of alcohol above 10 units/week resulted
in an 80% increased risk of new-onset AF (HR 1.8 (1.2, 2.9), p = 0.009) independently
of the other factors associated to risk of new-onset AF (age, male gender, treatment
allocation to losartan versus atenolol, and change over time in systolic blood
pressure, Cornell ECG measure of left ventricular hypertrophy and heart rate).
Smoking was not associated with more new atrial fibrillation, and the effect of
alcohol did not interact with the effect of smoking.
"Our results show that an intake of alcohol above 10
units per week increases the risk of new-onset AF, hence drinking up to 10 alcohol
units/week does not increase the risk of new-onset atrial fibrillation in hypertensive
patients with ECG left ventricular hypertrophy" says Inger Ariansen.
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