Delirium Among Hospitalized Older Adults With Acute Heart Failure Exacerbation

Background: Delirium among older adults hospitalized with acute heart failure is associated with increased mortality. However, studies concomitantly assessing the association of delirium with both clinical and economic outcomes in this population, such as mortality, hospital cost, or length of stay, are lacking.

Methods and results: We conducted a retrospective observational study using National Inpatient Sample data from 2011 to 2014. Using multivariable logistic regression, we assessed the association of delirium with in-hospital mortality, then estimated the incremental hospital cost and excessive length of stay adjusting for demographic and clinical factors using multivariable generalized linear regression. The association of other medical complications on clinical and economic outcomes was also assessed. A total of 568,565 (weighted N = 2,826,131) hospitalizations of patients 65 years or older with acute heart failure from 2011 to 2014 were included in the final analysis. The reported prevalence of delirium was 4.53%. After multivariable adjustment, delirium was associated with a 2.35-fold increase in the odds of in-hospital mortality (95% confidence interval [CI] 2.23-2.47), which was lower than the odds ratio for sepsis/septicemia (5.36; 95% CI, 5.02-5.72) or respiratory failure (4.53; 95% CI, 4.38-4.69), but similar to that for acute kidney injury (2.39; 95% CI, 2.31-2.48) and higher than for non-ST elevation myocardial infarct (1.57; 95% CI, 1.46-1.68). Delirium increased the total hospital cost by $4,262 (95% CI, $4,002-4,521) and the length of stay by 1.73 days (95% CI, 1.68-1.78), which was slightly lower than, but similar to, acute kidney injury ($4,771; 95% CI, $4,644-4,897) and 1.82 days (95% CI, 1.79-1.84), and higher than non-ST elevation myocardial infarct ($1,907; 95% CI, $1,629-2,185) and 0.31 days (95% CI, 0.25-0.37).

Conclusions: Delirium was associated with increased in-hospital mortality, total hospital cost, and length of stay, and the magnitude of the effect was similar to that for acute kidney injury. Enhanced efforts to prevent delirium are needed to decrease its adverse impact on clinical and economic outcomes for hospitalized older adults with acute heart failure.