This was some research published in the BMJ in June looking at ‘access to alcohol and heart disease among patients in hospital: observational cohort study using differences in alcohol sales laws’.
I’ll detail the abstract and then the relevant bits of the discussion which caught my eye:
Objective To investigate the relation between alcohol consumption and heart disease by using differences in county level alcohol sales laws as a natural experiment.
Design Observational cohort study using differences in alcohol sales laws.
Setting Hospital based healthcare encounters in Texas, USA.
Population 1 106 968 patients aged 21 or older who were residents of “wet” (no alcohol restrictions) and “dry” (complete prohibition of alcohol sales) counties and admitted to hospital between 2005 and 2010, identified using the Texas Inpatient Research Data File.
Outcome measures Prevalent and incident alcohol misuse and alcoholic liver disease were used for validation analyses. The main cardiovascular outcomes were atrial fibrillation, acute myocardial infarction, and congestive heart failure.
Results Residents of wet counties had a greater prevalence and incidence of alcohol misuse and alcoholic liver disease. After multivariable adjustment, wet county residents had a greater prevalence (odds ratio 1.05, 95% confidence interval 1.01 to 1.09; P=0.007) and incidence (hazard ratio 1.07, 1.01 to 1.13; P=0.014) of atrial fibrillation, a lower prevalence (odds ratio 0.83, 0.79 to 0.87; P<0.001) and incidence (hazard ratio 0.91, 0.87 to 0.99; P=0.019) of myocardial infarction, and a lower prevalence (odds ratio 0.87, 0.84 to 0.90; P<0.001) of congestive heart failure. Conversion of counties from dry to wet resulted in statistically significantly higher rates of alcohol misuse, alcoholic liver disease, atrial fibrillation, and congestive heart failure, with no detectable difference in myocardial infarction.
Discussions The relation between heart failure and alcohol use has been one of the more complex associations to elucidate. On the one hand, alcohol is known to cause cardiomyopathy.29 30 On the other hand, some studies have suggested that alcohol may have a protective effect when consumed in moderation.14 15 Both atrial fibrillation and myocardial infarction can lead to heart failure,31 32 with myocardial infarction likely being much the more important of the two.
The discordant results, showing more atrial fibrillation but less myocardial infarction and congestive heart failure in wet compared with dry counties, are particularly remarkable given that these outcomes generally share all of the same risk factors and that each can lead to the other. Specifically, atrial fibrillation predicts myocardial infarction and congestive heart failure,31 35 36 37 just as myocardial infarction predicts atrial fibrillation7 38 39 and congestive heart failure predicts atrial fibrillation.7 31 Therefore, given these potential “downstream” influences, these discordant results may suggest that the direct effects of alcohol are more potent than the point estimates reported.
Conclusions Greater access to alcohol was associated with more atrial fibrillation and less myocardial infarction and congestive heart failure, although an increased risk of congestive heart failure was seen shortly after alcohol sales were liberalized.
I’ve often wondered about alcohol and the heart and wanted to see some research to validate my experience. The youngest patient I ever nursed whose death was alcohol-caused was a 36 year old female who died of alcohol induced cardiac failure. Plus in the TV twin study a cardiologist used ultrasound to observe their heart during drinking and noticed cardiac dilation.
There was an editorial in the BMJ the same day titled ‘Pinpointing the health effects of alcohol‘ that critiqued this study that concluded with:
Both proponents and skeptics of the hypothesis that alcohol consumption reduces cardiovascular risk should recognize that nothing short of a randomized trial of alcohol consumption will provide the quality of data necessary to answer this question with confidence, because any observational design will be subject to serious limitations. All interested parties should press for such a trial quickly and wholeheartedly. It is time to move forward.
I look forward to reading the results of this RCT and also the detailed limitations and confounding variables!!
Edited to add:
Edited to add: 6th Feb 2017
The Express reported on research that found alcohol abuse was associated with a doubled risk of irregular heartbeat, a 1.4-fold increased risk of heart attack and a 2.3-fold increased risk of heart failure.