Objectives: To study the frequency of overlapping of delirium with neuropsychiatric symptoms (NPS) among patients with dementia, and to investigate the prognostic value of delirium, multiple NPS without delirium, or neither during a 2-year follow-up.
Methods: We assessed 425 consecutive patients in acute geriatric wards and in seven nursing homes in Helsinki. Those 255 suffering from dementia were examined for NPS of dementia described in the Neuropsychiatric Inventory (delusions, hallucinations, agitation/aggression, depression/low mood, anxiety, euphoria/elation, apathy, disinhibition, irritability/mood changes, and aberrant motor behavior) and for delirium criteria according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Patients were categorized into three groups: delirium with or without multiple NPS (delirium group), multiple NPS without delirium (multiple NPS group), or having neither delirium nor multiple NPS (zero or only one NPS group).
Results: A total of 66 patients suffered from delirium according to the DSM-IV, 127 had multiple NPS without delirium, and 62 had neither multiple NPS nor delirium. In the delirium group 61 individuals (92.4%) were deceased or residing in permanent institutional care at the end of the 2-year follow up period, compared to 100 individuals (78.7%) in the multiple NPS group and 48 (77.4%) in the zero or one NPS group (Pearson χ² = 6.64, df 2, p = 0.036). In logistic regression analysis adjusted for age, sex, and comorbidities, delirium was an independent predictor of this composite outcome (OR: 4.3, 95% CI: 1.4-13.6).
Conclusions: Patient groups with symptoms of delirium and multiple NPS are highly overlapping. The presence of delirium indicates poor prognosis.