The day of the week and acute heart failure admissions: Relationship with acute myocardial infarction, 30-day readmission rate and in-hospital mortality.

Background: In-hospital care may be constrained during the weekend due to lesser resources. Impact on outcomes of weekend versus weekday care in congestive heart failure (HF) needs further study.
Methods: Admissions with a primary diagnosis of HF using ICD-9CM codes were studied. 22,287 HF-admissions from Einstein Medical Center (2003-2013) and 2,248,482 HF-admissions from the 2002-2012 Nationwide Inpatient Sample (NIS) were analyzed separately. Primary outcomes were 30-day HF-readmission and in-hospital mortality. Logistic regression models were used to evaluate outcomes.
Results: Weekends experienced lower rates of admission and discharge. Mondays experienced the highest admission rate and Fridays experienced the highest discharge rate. Friday was independently associated with highest 30-day HF-readmission rates (Adjusted OR 1.12, CI 1.01-1.23; p=0.02) in addition to risk factors such as African-American race, hypertension, diabetes, hyperlipidemia, end-stage renal disease and coronary artery disease. Within the NIS sample, 85,479 in-hospital deaths (3.8%) were recorded. Compared to weekdays, patients admitted over the weekend had greater comorbidities, higher incidence of acute myocardial infarction (AMI) (15.8% vs. 16.8%; p<0.01), higher Charlson-comorbidity index and underwent less procedures such as echocardiography, right heart catheterization, coronary angiography, coronary revascularization or mechanical circulatory support. Weekend HF admission predicted higher in-hospital mortality (aOR 1.07, 95%CI 1.05-1.08; p<0.01) on multivariate analysis. This relationship was applicable for teaching and non-teaching hospitals.
Conclusion: Friday was associated with the highest discharge and 30-day HF-readmission rate. Weekend HF admissions experienced more AMI, had greater comorbidities, received less cardiac procedures and predicted higher in-hospital mortality. Higher weekend mortality may be related to the greater degree of severity of illness among admitted patients.
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