Incidence, prevalence and risk factors of delirium in ICU patients: A systematic review and meta-analysis

Background Delirium is one of the most common problems in intensive care units (ICU), and it has a detrimental influence on the patients' health. Estimating the prevalence of delirium in ICU patients and understanding the risk factors for delirium are crucial tasks. Objective To offer empirical support for early detection of the risk of delirium in ICU patients, we conducted a systematic review and meta-analysis to analyse the incidence? prevalence and risk factors of delirium in ICU patients. Methods From inception to 19th December 2021, PubMed, Embase, Cochrane Library, Web of Science, China Knowledge Resource Integrated Database (CNKI), Wanfang Database, Chinese Biomedical Database (CBM) and Weipu Database (VIP) were searched for inclusion to the study. The quality of the included studies was assessed by two investigators independently. The outcomes of the meta-analysis, which was conducted using the Stata 12.0 software, were reported using odds ratios (OR) and 95 percent confidence intervals (CI). Heterogeneity was determined using the I-2 statistic. Results In this meta-analysis, 51 studies with a total of 39 076 patients were evaluated. The incidence and prevalence of delirium in ICU patients were 31 per 1000 and 33%, respectively. A total of 28 risk factors were identified. Of these 28 risk factors, the top five modifiable risk factors were pain (OR = 19.74, 95% CI [8.86-30.61]), use of physical restraints (OR = 15.46, 95% CI [3.68-27.25]), respiratory diseases (OR = 14.3, 95% CaI [8.42-20.19]), sleep deprivation (OR = 9.4, 95% CI [6.8-12.1]) and surgery (OR = 8.98, 95% CI [7-15.27]). Non-modifiable risk factors included age (OR = 1.06, 95% CI[1.04, 1.07]) and gender (OR = 1.45, 95% CI[1.13, 1.77]). Of these 51 studies included in this analysis, 30 studies were shown with a low risk of bias while 21 studies were shown with a moderate risk of bias. Our results also demonstrated that 21 studies and 30 studies with intermediate methodological quality and low methodological quality respectively. Conclusion Delirium was shown to be prevalent among ICU patients. There are 28 risk factors for delirium that we discovered. These risk factors can assist physicians, nurses and other health care professionals prevent delirium in ICU patients. Relevance to practice Delirium in ICU patients can potentially be prevented through appropriate prevention strategies by intensive care staff.