Delirium in an adult acute hospital population: predictors, prevalence and detection

Abstract

BackgroundTo date, delirium prevalence and incidence in acute hospitals has been estimated from pooled findings of studies performed in distinct patient populations.ObjectiveTo determine delirium prevalence across an acute care facility.DesignA point prevalence study.SettingA large tertiary care, teaching hospital.Patients311 general hospital adult inpatients were assessed over a single day. Of those, 280 had full data collected within the study's time frame (90%).MeasurementsInitial screening for inattention was performed using the spatial span forwards and months backwards tests by junior medical staff, followed by two independent formal delirium assessments: first the Confusion Assessment Method (CAM) by trained geriatric medicine consultants and registrars, and, subsequently, the Delirium Rating Scale-Revised-98 (DRS-R98) by experienced psychiatrists. The diagnosis of delirium was ultimately made using DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) criteria.ResultsUsing DSM-IV criteria, 55 of 280 patients (19.6%) had delirium versus 17.6% using the CAM. Using the DRS-R98 total score for independent diagnosis, 20.7% had full delirium, and 8.6% had subsyndromal delirium. Prevalence was higher in older patients (4.7% if <50 years and 34.8% if >80 years) and particularly in those with prior dementia (OR=15.33, p<0.001), even when adjusted for potential confounders. Although 50.9% of delirious patients had pre-existing dementia, it was poorly documented in the medical notes. Delirium symptoms detected by medical notes, nurse interview and patient reports did not overlap much, with inattention noted by professional staff, and acute change and sleep-wake disturbance noted by patients.ConclusionsOur point prevalence study confirms that delirium occurs in about 1/5 of general hospital inpatients and particularly in those with prior cognitive impairment. Recognition strategies may need to be tailored to the symptoms most noticed by the detector (patient, nurse or primary physician) if formal assessments are not available.

Delirium: a guide for the general physician

“…6 Delirium is both common and dangerous, but current evidence suggests it is also preventable in about one third of cases, 7 hence the growing emphasis on the adoption of multicomponent delirium prevention interventions. Delirium prevalence is not bound by specialty 2 and crosses over to both hospital and community settings. 8 Given its ubiquity and its heterogeneous presentation, delirium diagnosis and management is the responsibility of all clinicians.…”

“…Over the age of 80 years, more than one third of those in hospital will experience delirium. 2 Despite its high prevalence, delirium often goes undetected 3 and undetected delirium is associated with the highest mortality. 4 Delirium heralds high risk of falls, longer inpatient stay, postdischarge institutionalisation, accelerated and lasting cognitive decline, and higher mortality.…”

Incidence of cholinesterase inhibitor therapy initiation among hospitalized patients

“…1,2 Delirium occurs in 20% of acute care patients and is 15 times more likely to occur in patients with prior dementia. 3 A hospitalized patient's baseline cognitive status can be difficult to ascertain in clinical practice, which makes it difficult to discriminate dementia from delirium or recognize dementia with superimposed delirium.…”

Ghosts in the health machine

“…Broadly speaking, the more extreme our state of health or the greater our vulnerability, the greater the likelihood that we will be subject to delirium in hospital. Thus, in a 'normal' hospital ward, about one in five people are likely to be delirious at any given time (Peter 2012;Ryan et al 2013). In intensive care, this figure rises to over 80 per cent (Maldonado 2008).…”