Delirium is a neurology conative disorder characterized by acute onset, disturbed consciousness and fluctuated course. In the emergency department (ED), the prevalence reported as high as 10–20%, and 8–25% of old patients in ED present with delirium. Studies have confirmed that patients with delirium tend to have poor outcomes including increased length of hospital stay, medical complications, increased risk of falls and higher mortality.
Although delirium is prevalent and associated with adverse outcomes, there is still three out of four patients missed delirium detection by bedside nurses and medical staff. Especially in the ED, the assessment of delirium is rarely done due to the high volume of patients and tense time demands on providers. In the United States, emergency physicians miss about 75% cases of delirium each year. Delirium screening is still a challenge for the ED staff. As the center of modern healthcare, ED should provide appropriate and rapid treatment in the first time. Therefore, it suggests a need for screening tools. Clinical practice guidelines recommend that a valid tool for delirium assessment is a crucial component in the detection of delirium. An accurate screening tool could identify high-risk patients to reduce or prevent delirium occurrence and reduce the burden of delirium.
Currently, several screening tools have been designed to support the assessment of delirium, but the screening in the ED has not been uniformly recognized. Different screening tools have a variety of sensitivities and specificities. The time needed to complete the assessments also adds to the complexity of delirium detection. Different guidelines provide different recommendations. The Scottish Intercollegiate Guidelines Network (SIGN) recommends that in the ED, the 4AT (Arousal, Attention, Abbreviated Mental Test 4, Acute change) tool should be used for identifying delirium. The National Institute for Health and Care Excellence (NICE) suggests that short Confusion Assessment Method (short CAM) should be routinely used to diagnosis delirium. Consequently, it is still not certain which screening tools to use in the ED.
Several systematic reviews have been conducted to summarize the finding of delirium screening tools in the ED, but they did not suggest which screening tool is better. Ewan et al. summarized the results for delirium assessment and concluded that there is variability in screening methodology, the procedures to obtain consent and the methodological quality. A validated screening method is urgently needed to identify delirium in the early time. Lamantia et al. concluded that there is still a lack of validated delirium screening tools in the ED. José et al. conducted a systematic search and found that the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) is the most widely used instrument, but not the most suitable for the ED. Although they all gave a comprehensive description of the screening tools for delirium in the ED, some studies focused on the effectiveness of screening tools rather than accuracy, and they did not conduct a quantitative meta-analysis to compare the different screening tools. With the emergence of new evidence, a systematic evaluation and meta-analysis is necessary. In addition, a pairwise meta-analysis could not provide a whole picture about the screening tools and assess the relevant diagnostic accuracy of different tools. Network meta-analysis has been used widely in interventional studies, that could compare the relevant effect of three or more interventions at the same time and effectively ranked the interventions to select the optimal treatment plan even in the absence of direct comparisons.
This study aimed to evaluate the accuracy of different screening tools for ED patients by using a network meta-analysis method, and to rank different methods of assessment using the superiority index (SI).