Coronary heart disease as a risk factor for delirium in older COVID-19 patients.

Abstract

Aim: Delirium during acute infection is associated with poor outcomes, although research is limited due to the heterogenous nature of affected populations. Identifying risk factors for delirium can help differentiate high-risk patients.

Methods: This retrospective study was carried out at a single COVID-19 designated hospital in Korea between February 2020 and May 2022. It analyzed the clinical and laboratory characteristics of COVID-19 patients aged ≥75 years. COVID-19, ranging from mild to severe, was diagnosed by polymerase chain reaction test, and delirium was diagnosed clinically. A binary logistic regression analysis was carried out using meaningful variables from descriptive analyses.

Results: Among the 1166 patients in the study population, 53 (4.5%) experienced delirium during the admission period. Patients with delirium were more likely to have been transferred from another hospital (24.5% vs. 12.4%, P = 0.018) and had higher body temperatures (37.4°C vs 37.1°C, P = 0.008). They also had a history of coronary heart disease, chronic kidney disease more frequently and showed higher C-reactive protein (19.2% vs 7.1%, P = 0.003; 13.5% vs 4.5%, P = 0.009; 6.2 mg/dL vs 4.8 mg/dL, P = 0.026). Patients with delirium more frequently required oxygen support, mechanical ventilation and transfer to a higher-level hospital (54.7% vs 35.7%, P = 0.008; 13.2% vs 4.1%, P = 0.006; 17.0% vs 7.0%, P < 0.001). Coronary heart disease was associated with a significantly higher odds ratio of 2.898 (95% confidence interval 1.118-6.696, P = 0.0182) in a multiple regression model.

Conclusion: A history of coronary heart disease was associated with a high risk of developing delirium during hospitalization for COVID-19 in patients aged ≥75 years. Patients with delirium experienced worse COVID-19-related outcomes. Geriatr Gerontol Int 2025; ••: ••-••.