Access to alcohol and heart disease among patients in hospital: observational cohort study using differences in alcohol sales laws

Abstract

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.

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.

Fig 1 Association between wet county residence and prevalent hospital admissions. Squares represent main and propensity score adjusted analyses odds ratios for prevalent alcohol misuse, alcoholic liver disease, atrial fibrillation, acute myocardial infarction, and congestive heart failure in wet county residents compared with dry county residents (see text for list of covariates included in each model)

Fig 2 Propensity score adjusted cumulative incidence for alcohol misuse, alcoholic liver disease, atrial fibrillation, acute myocardial infarction, and congestive heart failure admissions in dry and wet counties. Stratified by dry and wet counties in Texas between 1 January 2005 and 31 December 2010. Numbers in parentheses represent number at risk in study population. See text for the covariates included in each model

Fig 3 Change in incidence of alcoholic liver disease, alcohol misuse, atrial fibrillation, acute myocardial infarction, and congestive heart failure admissions before and after conversion from dry to wet county status. Squares represent change in incident rates for each type of hospital admission in seven counties that converted from dry to wet. Denominators for incident rates were determined using 2010 US census data. Incident difference is difference between incident rates before and after referendum for given outcome. Error bars indicate 95% confidence intervals