Risk factors for developing delirium in older patients admitted to general medical wards

Delirium in older patients is common and leads to poor clinical outcomes. It is, however, preventable if its risk factors are identified and modified accordingly.

To determine risk factors associated with delirium in hospitalized older patients admitted to general medical wards at Siriraj Hospital.

A prospective observational study was conducted at general medical wards, Siriraj Hospital. All consecutive patients aged 70 years or older admitted during study period were assessed and followed until discharge. A diagnosis of delirium was made if patients developed symptoms which fulfilled DSM IV criteria. Information regarding demographic data, co-morbid illnesses, preexisting cognitive status and functional status was collected at admission. Factorf associated with delirium were analyzed using logistic regression models.

Risk factors associated with developing delirium identified from univariate analysis were female gender, age more than 80 years-old, having 4 or more co-morbidities, azothemia, hyponatremia, presence of infection, severe illness, preexisting dementia, depression, and impaired basic activities of daily living. After adjusted in multivariate analysis; factors those remained statistically significant were preexisting dementia (OR = 5.52, 95% CI = 2.51-12.14), severe illness (OR = 5.18, 95% CI = 2.10-12.76) presence of infection (OR = 2.54, 95% CI = 1.15-5.61) and azothemia (OR = 2.55, 95% CI = 1.205.40).

Pre-existing dementia and illness severity were strongly associated with developing delirium in older patients in the present study, which is concordant with previous studies. Other factors such as presence of infection and azothemia are modifiable factors that could potentially be important targets, along with other factors identified in the present study, for implementing intervention in order to prevent delirium in this population.