Predisposing and precipitating factors for delirium in neurology: a prospective cohort study of 1487 patients.

INTRODUCTION: Predisposing and precipitating factors for delirium are well known; however, their interaction and impact on delirium in neurological patients remains largely unknown. Therefore, those factors were evaluated in hospitalized patients with neurological disorders.

METHODS: In this prospective cohort study, 1487 neurological patients were included, 356 patients with delirium and 1131 without delirium. Relevant neurological- and medical-related clusters were assessed with multiple regression analyses, prediction models, and cluster analysis evaluating their association with delirium.

RESULTS: The 1-year incidence of delirium in this cohort was 23.9%. Delirium developed in 31% of patients with stroke, in 39.5% with epilepsy, and in 58.4% with ICH. The most relevant predisposing factors were substance-use disorders (OR 4.24, 2.28-7.78, p < 0.001), advanced age (OR 3.44, CI 2.40-4.92, p < 0.001), and neurodegenerative disorders (OR 2.58, CI 1.47-4.54, p = 0.001). The most relevant precipitating factors were meningitis (OR 21.52, CI 1.22-379.83, p = 0.036), acute renal failure (OR 10.01, CI 1.13-88.73, p = 0.039), and intracranial hemorrhage (OR 3.62, CI 2.08-6.30, p < 0.001). Delirious patients were hospitalized 6 days longer, had higher in-hospital mortality, and were discharged more often to nursing homes and rehabilitation. Best predictor for delirium was the coexistence of advanced age with epilepsy (58.3%, p < 0.001), while patients aged < 65 years without epilepsy and stroke rarely developed delirium (5.1%, p < 0.001).

CONCLUSIONS: Delirium is common in elder neurological patients and associated with worse outcome. Primary cerebral conditions most frequently precipitate delirium in neurology. Neurologists are advised to monitor symptoms of delirium in the presence of risk factors to enable both timely diagnostic work-up and management of delirium.