Prevalence of Delirium in a Population of Elderly Outpatients with Dementia: A Retrospective Study

To validate a chart-based method for identification of delirium and compare it with direct interviewer assessment using the Confusion Assessment Method (CAM). Prospective validation study. Teaching hospital. Nine hundred nineteen older hospitalized patients. A chart-based instrument for identification of delirium was created and compared with the reference standard interviewer ratings, which used direct cognitive assessment to complete the CAM for delirium. Trained nurse chart abstractors were blinded to all interview data, including cognitive and CAM ratings. Factors influencing the correct identification of delirium in the chart were examined. Delirium was present in 115 (12.5%) patients according to the CAM. Sensitivity of the chart-based instrument was 74%, specificity was 83%, and likelihood ratio for a positive result was 4.4. Overall agreement between chart and interviewer ratings was 82%, kappa=0.41. By contrast, using International Classification of Diseases, Ninth Revision, Clinical Modification, administrative codes, the sensitivity for delirium was 3%, and specificity was 99%. Independent factors associated with incorrect chart identification of delirium were dementia, severe illness, and high baseline delirium risk. With all three factors present, the chart instrument was three times more likely to identify patients incorrectly than with none of the factors present. A chart-based instrument for delirium, which should be useful for patient safety and quality-improvement programs in older persons, was validated. Because of potential misclassification, the chart-based instrument is not recommended for individual patient care or diagnostic purposes.

delirium is a common clinical problem and is associated with adverse health outcomes. Many medications have been associated with the development of delirium, but the strength of the associations is uncertain and it is unclear which medications should be avoided in people at risk of delirium. we conducted a systematic review to identify prospective studies that investigated the association between medications and risk of delirium. A sensitivity analysis was performed to construct an evidence hierarchy for the risk of delirium with individual agents. a total of 18,767 studies were identified by the search strategy. Fourteen studies met the inclusion criteria. Delirium risk appears to be increased with opioids (odds ratio [OR] 2.5, 95% CI 1.2-5.2), benzodiazepines (3.0, 1.3-6.8), dihydropyridines (2.4, 1.0-5.8) and possibly antihistamines (1.8, 0.7-4.5). There appears to be no increased risk with neuroleptics (0.9, 0.6-1.3) or digoxin (0.5, 0.3-0.9). There is uncertainty regarding H(2) antagonists, tricyclic antidepressants, antiparkinson medications, steroids, non-steroidal anti-inflammatory drugs and antimuscarinics. for people at risk of delirium, avoid new prescriptions of benzodiazepines or consider reducing or stopping these medications where possible. Opioids should be prescribed with caution in people at risk of delirium, but this should be tempered by the observation that untreated severe pain can itself trigger delirium. Caution is also required when prescribing dihydropyridines and antihistamine H1 antagonists for people at risk of delirium and considered individual patient assessment is advocated.

Deficits in cholinergic function have been postulated to cause delirium and cognitive decline. This review examines current understanding of the cholinergic deficiency hypothesis in delirium by synthesizing evidence on potential pathophysiological pathways. Acetylcholine synthesis involves various precursors, enzymes, and receptors, and dysfunction in these components can lead to delirium. Insults to the brain, like ischemia and immunological stressors, can precipitously alter acetylcholine levels. Imbalances between cholinergic and other neurotransmitter pathways may result in delirium. Furthermore, genetic, enzymatic, and immunological overlaps exist between delirium and dementia related to the cholinergic pathway. Important areas for future research include identifying biomarkers, determining genetic contributions, and evaluating response to cholinergic drugs in delirium. Understanding how the cholinergic pathway relates to delirium may yield innovative approaches in the diagnosis, prevention, and treatment of this common, costly, and morbid condition.