Critique 010: Alcohol following a myocardial infarction
Critique 010 30 June 2010
Carter MD, Lee JH, Buchanan DM, Peterson ED, Tang F, Reid KJ, Spertus JA, Valtos J, O’Keefe JH. Comparison of outcomes among moderate alcohol drinkers before acute myocardial infarction to effect of continued versus discontinuing alcohol intake after the infarct. Am J Cardiol 2010 (Published early online).
Light-to-moderate alcohol consumption has been previously associated with a lower risk of acute myocardial infarction (AMI) and mortality. The association of changes in drinking behavior after an AMI with health status and long-term outcomes is unknown. Using a prospective cohort of patients with AMI evaluated with the World Health Organization’s Alcohol Use Disorders Identification Test, we investigated changes in drinking patterns in 325 patients who reported moderate drinking at the time of their AMI. One-year alcohol consumption, disease-specific (angina pectoris and quality of life) and general (mental and physical) health status and re-hospitalization outcomes, and 3-year mortality were assessed. Seattle Angina Questionnaire Angina Frequency and Quality of Life, Short Form-12 Mental and Physical Component Summary Scales were modeled using multivariable hierarchical linear models within site.
Of the initial 325 moderate drinkers at baseline, 273 (84%) remained drinking and 52 (16%) quit. In fully adjusted models, Physical Component Scale scores (beta 6.47, 95% confidence interval 3.73 to 9.21, p < 0.01) were significantly higher during follow up in those who remained drinking. Persistent moderate drinkers had a trend toward less angina (relative risk 0.65, 95% confidence interval 0.39 to 1.10, p = 0.11), fewer re-hospitalizations (hazard ratio 0.79, 95% confidence interval 0.44 to 1.41, p = 0.42), lower 3-year mortality (relative risk 0.75, 95% confidence interval 0.23 to 2.51, p = 0.64), and better disease-specific quality of life (Seattle Angina Questionnaire Quality of Life, beta 3.88, 95% confidence interval -0.79 to 8.55, p = 0.10) and mental health (Mental Component Scale, beta 0.83, 95% confidence interval -1.62 to 3.27, p = 0.51) than quitters. In conclusion, these data suggest that there are no adverse effects for moderate drinkers to continue consuming alcohol and that they may have better physical functioning compared to those who quit drinking after an AMI.
There has been considerable recent interest in the effects of alcohol consumption following an acute myocardial infarction (AMI) or other evidence of coronary artery disease. In this paper, among 325 subjects who were moderate drinkers prior to an AMI, 84% continued to drink and 16% quit. While most of the outcome measures showed no statistically significant effects, all showed a tendency towards better physical and mental health outcomes for persistent drinkers. A number of previous studies1-6 have suggested that, except for binge drinking, alcohol intake following the diagnosis of cardiovascular disease is associated with a lower risk of cardiovascular and total mortality.
Comments on this paper
The number of subjects in this study was relatively small, and it is surprising that “moderate drinking” was the exception rather than the rule among the middle-aged US white males in this study. Screening of the 2,498 patients enrolled in the parent study found only 325 patients who reported moderate drinking; it would be interesting to see results if other criteria were used to define “moderate drinking.”
Few characteristics of the two groups are presented, and quitters may have been a sicker group to begin with, possibly with a larger infarct size and poorer left ventricular function following the infarct which would render them physically and emotionally weaker and foreshadow a poorer prognosis. Other important data are not provided that could affect differences between the two groups: these include extent of coronary artery disease, degree and success of revascularization post infarction, average door-to-balloon time in patients undergoing rescue percutaneous coronary intervention (PCI), post infarction left ventricular ejection fraction, etc. There were fewer Caucasians in the quitting group 36(69%) than the moderate drinking group 256(94%). Further, there were more people with congestive cardiac failure in the quitting group (12%) than the moderate drinking group7(3%).
The authors’ conclusion “these data suggest that there are no adverse effects for moderate drinkers to continue consuming alcohol” may well be true, and is hardly surprising given the known beneficial effects of moderate alcohol intake among patients with cardiovascular disease. This has been shown in most previous studies, as is summarized well in a recent meta-analysis by Costanzo et al.3
Problems with observational data
A key problem with this analysis, and with all observational epidemiologic studies on this topic, is that the reason that some subjects (16% in this study) stopped drinking after having an AMI is not known. Even though adjustments were made for most known factors associated with not drinking, residual confounding may be the reason that these subjects had poorer outcomes than those who persisted in their alcohol consumption. It may well require a randomized trial, in which subjects having an AMI are advised to continue to drink or to avoid alcohol, to be able to determine reliably the effects of the persistence of alcohol intake following an AMI.
Implications for physicians’ advice to patients
Moderate alcohol consumption has been shown to have a strong and consistent negative predictive effect on the development of atherosclerotic disease. The epidemiologic data are supported by a growing body of plausible biologic mechanisms for this benefit. Thus, current data provide little support for physicians to recommend cessation of alcohol consumption after myocardial infarction. Further, there is little evidence that moderate drinking interferes with cardiac medications, including anti-coagulants, and enhanced hepatotoxicity with drugs such as statins is unsubstantiated. Cardiomyopathy seen with heavy alcohol consumption is not a feature of moderate consumption; in fact, data suggest that moderate drinkers have a lower risk of congestive heart failure. Because of limitations inherent in observational studies, however, clinical trials may be required for definitive data on the potential benefits of the continuation of moderate drinking following an AMI or after other evidence of cardiovascular disease.
References from Forum Comments
1. Mukamal KJ. Alcohol use and prognosis in patients with coronary heart disease. Prev Cardiol 2003;6:93-98.
2. Mukamal KJ, Maclure M, Muller JE, Mittleman MA. Binge drinking and mortality after acute myocardial infarction. Circulation 2005;112:3839-3845.
3. Costanzo S, Di Castelnuovo A, Donati MB, Iacoviello L, de Gaetano G. Alcohol consumption and mortality in patients with cardiovascular disease. A meta-analysis. J Am Coll Cardiol 2010;55:1339–1347.
4. Costanzo S, Di Castelnuovo A, Donati MB, Iacoviello L, de Gaetano G. Contemporary Reviews in Cardiovascular Medicine. Cardiovascular and overall mortality risk in relation to alcohol consumption in patients with cardiovascular disease. Circulation 2010;121;1951-1959.
5. Goldfinger T, Koshkarian G, Tunstall A, McArdle C. The effects of alcohol consumption on recurrent ischemic events after percutaneous transluminal coronary interventions. CVRR 2001;2283-2286.
6. Niroomand F, Hauer O, Tiefenbacher CP, Katus HA, Kuebler W. Influence of alcohol consumption on restenosis rate after percutaneous transluminal coronary angioplasty and stent implantation. Heart 2004;90:1189–1193.
There has been considerable recent interest in the effects of alcohol consumption following an acute myocardial infarction (AMI). In this paper, among 325 subjects who were moderate drinkers prior to an AMI, 84% continued to drink and 16% quit. While most of the outcome measures showed no statistically significant effects between the two groups of patients, all outcomes showed a tendency towards better physical and mental health outcomes for persistent drinkers.
A key problem with this analysis, and with all observational epidemiologic studies on this topic, is that the reason that some subjects stopped drinking after having an AMI, while others continued to drink, is not known. Even though adjustments were made for many known related factors, there is always the possibility that subjects who stopped drinking were “sicker” in many ways than those who persisted in their alcohol consumption.
It may well require a randomized trial, in which some subjects having an AMI are randomly advised to continue to drink and others advised to stop drinking, to be able to determine reliably the effects on the clinical course of the persistence of alcohol intake following an AMI.
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Contributions to this critique by the International Scientific Forum on Alcohol Research were from the following:
Giovanni de Gaetano, MD, PhD, Research Laboratories, Catholic University, Campobasso, Italy
R. Curtis Ellison, MD, Section of Preventive Medicine & Epidemiology, Boston University School of Medicine, Boston, MA, USA
Harvey Finkel, MD, Hematology/Oncology, Boston University Medical Center, Boston, MA, USA
Tedd Goldfinger, DO, FACC, Desert Cardiology of Tucson Heart Center, Dept. of Cardiology, University of Arizona School of Medicine, Tucson, Arizona, USA
Ross McCormick PhD, MSC, MBChB, Associate Dean, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
Erik Skovenborg, MD, Scandinavian Medical Alcohol Board, Practitioner, Aarhus, Denmark