Prevalence, risk factors and impact of delirium in adult inpatients in a tertiary care hospital: A point prevalence study.

AIMS: To describe the point prevalence, risk factors and possible outcomes of delirium in inpatients.

DESIGN: A cross-sectional point prevalence study.

BACKGROUND: Delirium is an acute brain syndrome that negatively affects patients, healthcare professionals and institutions alike; it is common in inpatient settings and is preventable in about one third of cases. Although guidelines recommend systematic screening and assessment, delirium is often unrecognised, undiagnosed and uncoded. There is a lack of valid data on this patient safety indicator in German-speaking countries.

METHODS: The study was conducted in a tertiary care hospital in Switzerland on 5 July 2022. Specially trained registered nurses collected data from all patients meeting the inclusion criteria using CAM, ICDSC or mCAM-ED. Data were analysed descriptively with stratification by delirium status, setting and surgery.

RESULTS: The point prevalence across all settings was 6.9% (27/390), with large variation between settings: ICU 28.6% (4/14), IMC 28.0% (7/25), wards 4.6% (15/326) and ED 4% (1/25). Surgical patients were almost twice as likely to be affected as medical patients (8.9% vs. 4.8%). Patients with delirium differed most clearly from those without by having a larger number of ICD-10 F-diagnoses, a larger number of medications and higher age, which are known risk factors. Moreover, those with delirium had more missed diagnoses, increased mortality, more adverse events and higher costs.

CONCLUSIONS: A significant number of patients experienced delirium and adverse clinical outcomes. Missed delirium diagnoses may further jeopardise patient safety and result in lost revenue. It remains unclear to what extent the risk factors and effects of delirium are causal and what determinants underlie missed diagnoses.

RELEVANCE TO CLINICAL PRACTICE: Consistent identification of high-risk patients and treatment settings with elevated risk, accompanied by the implementation of effective preventive and management strategies, is critical to addressing delirium.