Presurgical screening improves risk prediction for delirium in elective surgery of older patients: the PAWEL RISK study
Creators: name: Eschweiler, Gerhard W.
name: Czornik, Manuel
name: Herrmann, Matthias L.
name: Knauer, Yvonne P.
name: Forkavets, Oksana
name: Von Arnim, Christine A. F.
name: Denkinger, Michael
name: Küster, Olivia
name: Conzelmann, Lars
name: Metz, Brigitte R.
name: Maurer, Christoph
name: Kentischer, Felix
name: Deeken, Friederike
name: Sánchez, Alba
name: Wagner, Sören
name: Mennig, Eva
name: Thomas, Christine
name: Rapp, Michael A.
Publisher: name: Universität Ulm
Year: 2021
Subjects: subject: postoperative delirium
subject: elective surgery
subject: cognitive assessment
subject: cognitive impairment
subject: risk prediction
subject: frailty
subject: geriatric assessments
subject: acute encephalopathy
subject: DDC 610 / Medicine &amp; health
subject: Delirium
subject: Postoperative complications
subject: Aged
subject: Risk factors
subject: Risk assessment
subject: Delirium
subject: Postoperative Phase
subject: Alter
subject: Risikofaktor
subject: Risikoanalyse

description: Introduction: The number of elective surgeries for patients who are over 70 years of age is continuously growing. At the same time, postoperative delirium (POD) is common in older patients (5–60%) depending on predisposing risk factors, such as multimorbidity, cognitive impairment, neurodegenerative disorders and other dementing disorders, and precipitating factors, such as duration of surgery. Knowledge of individual risk profiles prior to elective surgery may help to identify patients at increased risk for development of POD. In this study, clinical and cognitive risk factors for POD were investigated in patients undergoing various elective cardiac and non-cardiac surgeries. Methods: The PAWEL study is a prospective, interventional trial on delirium prevention. At baseline, 880 inpatients at five surgical centers were recruited for sub-sample PAWEL-R. Multimodal assessments included clinical renal function, medication, American Society of Anesthesiologists (ASA) Physical Status Classification System, geriatric and cognitive assessments, which comprised the Montreal Cognitive Assessment Scale (MoCA), Trail-making Test, and Digit Span backward. Delirium incidence was monitored postoperatively by the Confusion Assessment Method (CAM) and a chart review for up to a week or until discharge. Multivariate regression models and Chi-square Automatic Interaction Detectors (CHAID) analyses were performed using delirium incidence as the primary outcome. Results: Eighteen risk factors were investigated in elective cardiovascular and orthopedic or general surgery. A total of 208 out of 880 patients (24%) developed POD. A global regression model that included all risk variables predicted delirium incidence with high accuracy (AUC = 0.81; 95% CI 0.77, 0.85). A simpler model (clinical and cognitive variables; model CLIN-COG) of 10 factors that only included surgery type, multimorbidity, renal failure, polypharmacy, ASA, cut-to-suture time, and cognition (MoCA, Digit Span backward, and preexisting dementia), however, exhibited similar predictive accuracy (AUC = 0.80; 95% CI 0.76, 0.84). Conclusion: The risk of developing POD can be estimated by preoperative assessments, such as ASA classification, expected cut-to-suture time, and short cognitive screenings. This rather efficient approach predicted POD risk over all types of surgery. Thus, a basic risk assessment including a cognitive screen can help to stratify patients at low, medium, or high POD risk to provide targeted prevention and/or management strategies for patients at risk.