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Journal Club. Alcohol and Health: Current Evidence January-February 2005. Featured Article. Alcohol and Risk of Atrial Fibrillation or Flutter: A Cohort Study Frost L, Vestergaard P. Arch Intern Med . 2004;164(18):1993-1998. Study Objective. To examine the association between
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Journal Club Alcohol and Health: Current Evidence January-February 2005 www.alcoholandhealth.org
Featured Article Alcohol and Risk of Atrial Fibrillation or Flutter: A Cohort Study Frost L, Vestergaard P. Arch Intern Med. 2004;164(18):1993-1998. www.alcoholandhealth.org
Study Objective To examine the association between • alcohol consumption and • the risk of atrial fibrillation (AF) or flutter www.alcoholandhealth.org
Study Design • Researchers prospectively studied 47,949 Danish participants (mean age, 56 years) over a mean follow-up of 6 years. www.alcoholandhealth.org
Assessing Validity of an Article about Prognosis • Are the results valid? • What are the results? • How can I apply the results to patient care? www.alcoholandhealth.org
Are the Results Valid? • Was the sample representative? • Were the subjects sufficiently homogeneous with respect to prognostic risk? • Was follow-up sufficiently complete? • Were objective and unbiased outcome criteria used? www.alcoholandhealth.org
Was the sample representative? • The sample was somewhat representative of people in Denmark since it was drawn from Danish population-based registries. • Representativeness is limited due to the following: • Exclusion of those with endocrine or cardiovascular disease • Participation by fewer than two-thirds of those invited www.alcoholandhealth.org
Were the subjects sufficiently homogeneous with respect to prognostic risk? • Researchers excluded participants with cardiovascular disease (including AF or flutter), making the sample an inception cohort. • Men consuming amounts in the highest quintile drank approximately 6 standard drinks per day; women in the highest quintile drank about 3 drinks per day. www.alcoholandhealth.org
Was follow-up sufficiently complete? • Follow-up was 6 years on average but varied from <1 to 8 years. • The authors seem to suggest that follow-up (involving survival methods that censored subjects at the time of AF or flutter, death, emigration, or the end of the study) was 100%, assuming that all events would be captured for all people in the national registries used. www.alcoholandhealth.org
Were objective and unbiased outcome criteria used? • Yes; cases were identified by diagnostic codes and confirmed by electrocardiographic tracings. • But since these data were collected in the course of clinical care, diagnosis could possibly be biased (e.g., greater or lesser likelihood of recording AF or flutter based on a patient’s alcohol use). www.alcoholandhealth.org
What are the Results? • How likely are the outcomes over time? • How precise are the estimates of likelihood? www.alcoholandhealth.org
How likely are the outcomes over time? www.alcoholandhealth.org
How precise are the estimates of likelihood? • Although the confidence intervals for the hazard ratios in men did not all exclude 1, the p value for trend was 0.04. • The association between intake and AF or flutter in women was not statistically significant. www.alcoholandhealth.org
How Can I Apply the Results to Patient Care? • Were the study patients and their management similar to those in my practice? • Was the follow-up sufficiently long? • Can I use the results in the management of patients in my practice? www.alcoholandhealth.org
Were the study patients similar to those in my practice? • Given that the study involved a population-based cohort, subjects were not necessarily patients. • Whether (and how) these Danish subjects/patients might differ from those in the United States is not clear. www.alcoholandhealth.org
Was the follow-up sufficiently long? • Follow-up may not have been long enough: • Outcomes were not common. • AF or flutter is more prevalent in the elderly (the mean age of subjects at enrollment was 56 years). www.alcoholandhealth.org
Can I use the results in the management of patients in my practice? • Drinking even moderate amounts of alcohol may increase the risk of AF or flutter, at least for men. • This study did not have a large sample of heavy drinkers and therefore could not focus on the well-described “holiday heart.” www.alcoholandhealth.org
Can I use the results in the management of patients in my practice (cont.)? • It is not clear whether results would apply to people in the United States where drinking patterns may differ than those in Denmark. • AF or flutter is only one of the risks to consider when counseling patients about their drinking. www.alcoholandhealth.org