Effect of Morphine Used to Relieve Dyspnea Due to Heart Failure on Delirium

Background: Delirium management is crucial in palliative care. Morphine effectively relieves dyspnea due to heart failure. However, the effect of morphine, which is used to relieve dyspnea due to heart failure, on the incidence of delirium has not been examined to date. Objective: To evaluate the effect of morphine, which is used to relieve dyspnea due to heart failure, on delirium. Design: Retrospective observational study. Setting/Subjects: Subjects were identified from Osaka University Hospital records, located in Japan, from January 1, 2010, to September 30, 2021. The case group consisted of admissions for heart failure or cardiomyopathy registered in electronic medical records. Morphine was administered to relieve dyspnea due to heart failure, and no surgeries or procedures were performed. The control group consisted of admissions for heart failure or cardiomyopathy in the Diagnosis Procedure Combination (DPC) database, which did not include administration of morphine, oxycodone, or fentanyl during the hospitalization period and patients did not undergo surgery or any other procedure. Measurements: The incidence of delirium was assessed. Results: The odds ratios for morphine in the multivariate logistic regression analysis with propensity score and univariate logistic regression analysis after propensity score matching were 1.406 (95% confidence interval (CI) [0.249-7.957]) and 1.034 (95% CI [0.902-1.185]), respectively. Conclusions: Morphine, which is used to relieve dyspnea due to heart failure, had minimal effect on the incidence of delirium. This information is likely to be beneficial for the future use of morphine in the management of dyspnea in patients with heart failure.