Delirium is an important predictor of mortality in elderly patients with ST-elevation myocardial infarction: insight from National Inpatient Sample database.

Abstract

Delirium is a frequently encountered clinical condition in hospitalized patients and is known to be associated with poor outcomes. This study aims to assess the impacts of delirium in elderly patients undergoing percutaneous coronary intervention (PCI) following ST-elevation myocardial infarction (STEMI). We queried the National Inpatient Samples from 2010 to 2014 to identify all patients aged 65 and older, and admitted with a primary diagnosis of STEMI undergoing PCI by using the International Classification of Diseases-Ninth Edition-Clinical Modification diagnosis codes. The patients with delirium from this cohort were further evaluated. Multivariate regression model with SPSS Statistics 25.0 (IBM Corp., Armonk, New York, USA) was used to study the association between delirium and clinical outcomes including in-hospital mortality and length of stay (LOS). Out of weighted 42 980 patients aged ≥65 years with STEMI and PCI, delirium was present in 774 patients, accounting for 1.8% of this cohort. These patients were found to be older and had more underlying co-morbidities, compared to those without delirium [Median Charlson score 2 (1; 3) vs. 0 (0; 2); P < 0.001]. In-hospital mortality in STEMI patients with delirium was significantly higher than those without delirium [42.7% vs. 7.6%; unadjusted odds ratio (OR) 9.07; 95% confidence interval (CI) 6.55-12.57; P < 0.001; adjusted OR 1.86; 95% CI 1.13-3.04; P = 0.014]. Older age and comorbidities are known predisposing factors for delirium, which is in turn associated with higher in-hospital mortality and increased LOS in elderly patients with STEMI who undergo PCI. This study underscores the role of delirium and implicates the importance of further studies in recognition and targeted care of delirium.