104 PART THREE | DELIRIUM and metabolic imbalances within patients who had both an admittance with delirium and an admittance without delirium (27/52 patients with delirium). Admittances with delirium were significantly more often unscheduled than admittances without delirium (25/27 vs. 10/27, p<.001). Metabolic imbalances were also more prevalent in the delirium admittance than in the admittancewithout delirium, but this differencewas not statistically significant (12/27 vs. 6/27, p= .08). During the admittance with delirium, patients had a higher chance to be in the high-risk group according to the prediction algorithm (with the combination of an unscheduled admittance and metabolic imbalances), than during the admittance without delirium (12/27 resp. 4/27, p= .02). Discussion In this study, medical data from 574 patients during 1733 admittances were evaluated to determine the occurrence of delirium and its risk factors in patients admitted to the hospital for treatment or palliative care. We found a delirium incidence rate of 3.5 per 100 admittances and determined that nine percent of all patients admitted in this period developed delirium. The most frequent predisposing factors in this group of patients were age >70 and alcohol/drug abuse, while the most frequent precipitating factors were high doses of psychotropic medication, infection, constipation, and metabolic imbalance. Because of the large number of patients that were evaluated, it was possible to use both predisposing and precipitating factors to develop an algorithm that may be used in daily practice to identify patients with a high risk to develop a delirium. The incidence rate of 3.5 percent per admittance in this evaluation is lower than the 16-18 percent reported on similar hospital wards [6, 9]. A reason for the low incidence of delirium on this ward could be that half of the admittances were scheduled for patients to receive chemotherapy or undergo other interventions, as these patients have a low risk at delirium. In the study by Ljubisavljevic and Kelly [9], these patients were not included, and it is likely that the proportion of scheduled admittances in the study by Gaudreau et al [6] was also smaller. When all scheduled admissions are excluded from our dataset, the incidence rate of delirium goes up to 7.8 percent (57/730), which is still lower than in the aforementioned studies. Another important reason that might explain this low incidence rate could be that the mean age of the patients admitted to this ward was 60 years (only 21% of the patients were aged ≥70 years) and even the elderly patients had a good cognitive performance status, as only 2.1 percent of all patients had a cognitive impairment. The selected predisposing and precipitating factors were previously defined for their significant relationship with delirium, but this relationship was not confirmed for all of these factors in this study. This is most likely due to the low prevalence rates of these risk factors. In other studies logistic regression analysis to determine the influence of an individual factor on a patients risk at delirium have been used [8, 23]. Although the results of these analyses indicate that a patient in whom a certain factor is present has a relatively higher risk at delirium, it does not provide the clinician with a clinical tool to clearly define the absolute risk that a specific patient has to develop delirium. Also, the effect of a combination of multiple predisposing and/or precipitating factors in the
RkJQdWJsaXNoZXIy MjY0ODMw