The consequences of an incident delirium (ID) are multiple and severe among the hospitalized elderly patients. Many medications are recognized risk factors for delirium. The aim of this study was to determine the incidence of ID in an acute geriatric unit and to assess the role of iatrogenic factors among the precipitating factors of ID.

The study included 369 consecutive incident patients who were admitted in our Acute Geriatric Unit between January and April 2013. Delirium was diagnosed with the Confusion Assessment Method on a daily basis. The Naranjo criteria were used to determine iatrogenic causes of the ID.

During the study, 34 (9.2%) patients exhibited 35 ID. A multifactorial origin was found in 26 (75%) of these ID. A therapeutic change likely to promote an ID was found for 11 of these ID. According to the criteria of Naranjo, seven (20%) of these ID were likely to have iatrogenic origins. Only one of these seven ID was caused exclusively by iatrogenic factors. Medication was less frequently implicated as a precipitating factor of ID than metabolic factors (n=33; 94.4%), sources of discomfort (n=29; 82.8%), or acute medical problems (n=30; 85.7%).

The incidence of ID was about 10% in our acute geriatric unit. Iatrogenic factors were implicated in only one out of five ID and they were not among the three most common precipitating factors of ID.