Impact of delirium on mortality in patients hospitalized for heart failure

Objective Heart Failure (HF) is one of the leading causes of hospitalization in the United States accounting for approximate to 800,000 hospital discharges and $11 billion in annual costs. Delirium occurs in approximately 30% of elderly hospitalized patients and its incidence is significantly higher among those admitted to the critical care units. Despite this, there has been limited exploration of the clinical and economic impact of delirium in patients hospitalized with acute HF. We hypothesized that delirium in HF is associated with excess mortality and hospital costs. Methods We queried the 2001-2014 Nationwide Inpatient Sample to identify hospitalizations that included a primary discharge diagnosis of HF (ICD-9-CM: 428.xx) and stratified them by presence or absence of delirium (ICD-9-CM: 239.0, 290.41, 293.0, 293.1, 348.31). Differences in in-hospital mortality, length of stay (LOS), and hospital costs were assessed using propensity-score matched cohorts. Results Major predictors of delirium included advanced age, Caucasian race, underlying dementia or psychiatric diagnoses, higher Elixhauser Comorbidity Index, renal failure, cardiogenic shock, and coronary artery bypass surgery. In the propensity-score matched analysis of 76,411 hospitalization with delirium compared to 76,612 without delirium, in-hospital mortality (odds ratio: 1.67, 95% CI: 1.51-1.77), LOS (rate ratio [RR]: 1.47, 95% CI: 1.45-1.51), and hospital costs (RR: 1.44, 95% CI: 1.41-1.48) were all statistically higher in the presence of delirium (all p < 0.001). Conclusion In patients hospitalized with HF, delirium is an independent predictor of increased in-hospital mortality, longer LOS, and excess hospital costs despite adjustment for baseline characteristics.