A Systematic Review and Meta-analysis Examining the Impact of Incident Postoperative Delirium on Mortality

Abstract

Background Delirium is an acute and reversible geriatric syndrome that represents a decompensation of cerebral function. Delirium is associated with adverse postoperative outcomes, but controversy exists regarding whether delirium is an independent predictor of mortality. Thus, we assessed the association between incident postoperative delirium and mortality in adult noncardiac surgery patients. Methods A systematic search was conducted using Cochrane, MEDLINE/PubMed, Cumulative Index to Nursing and Allied Health Literature, and Embase. Screening and data extraction were conducted by two independent reviewers. Pooled-effect estimates calculated with a random-effects model were expressed as odds ratios with 95% CIs. Risk of bias was assessed using the Cochrane Risk of Bias Tool for Non-Randomized Studies. Results A total of 34 of 4,968 screened citations met inclusion criteria. Risk of bias ranged from moderate to critical. Pooled analysis of unadjusted event rates (5,545 patients) suggested that delirium was associated with a four-fold increase in the odds of death (odds ratio = 4.12 [95% CI, 3.29 to 5.17]; I2 = 24.9%). A formal pooled analysis of adjusted outcomes was not possible due to heterogeneity of effect measures reported. However, in studies that controlled for prespecified confounders, none found a statistically significant association between incident postoperative delirium and mortality (two studies in hip fractures; n = 729) after an average follow-up of 21 months. Overall, as study risk of bias decreased, the association between delirium and mortality decreased. Conclusions Few high-quality studies are available to estimate the impact of incident postoperative delirium on mortality. Studies that controlled for prespecified confounders did not demonstrate significant independent associations of delirium with mortality.

Impact of delirium on short‐term outcomes in hip fracture patients under a program of approach to delirium

“…26 As opposed to a longer length of stay observed in other studies, we achieved an earlier discharge, possibly accounting for the high percentage of HF dementia patients coming from nursing homes. 5 According to the current literature and the positive outcomes of our study, involving geriatricians in the implementation of specific strategies for the prevention of delirium in HF patients might reduce adverse outcomes associated with delirium. 27 However, and in line with our results, a recent metaanalysis showed that delirium was not significantly associated with mortality.…”

“…5 The ability to carry out the ADL was classified according to the usual cut-off points of the BI. Patients' walking ability was classified by the Red Cross Physical Scale 16 into able to walk independently (0-2), able to walk with the assistance of other persons 3,4 and unable to walk.…”

“…3 Given the consequences of delirium and its high prevalence in HF patients, the identification of people at risk of developing delirium, and the implementation of strategies to reduce and prevent its morbidity are highly desirable. 1,4,5 Dementia, functional decline, vision impairment, history of alcohol abuse and advanced age are the leading factors associated with delirium that have been recognized on admission in both medical and non-cardiac surgery populations. 1,4,5 Dementia, functional decline, vision impairment, history of alcohol abuse and advanced age are the leading factors associated with delirium that have been recognized on admission in both medical and non-cardiac surgery populations.…”

Predicting postoperative delirium severity in older adults: The role of surgical risk and executive function

“…30 The strengths of this study include its prospective perioperative design, statistical methods chosen, and rigorous delirium assessments including outcomes based on severity and incidence of delirium. Furthermore, a recent systematic review questioned the strength of the association between postoperative delirium and mortality; hence, a priori we hypothesized that NSQIP-SC would perform better than NSQIP-D for predicting postoperative delirium severity and incidence.…”

“…In contrast, an individual with fewer predisposing risk factors will require a large stimulus to precipitate delirium. 30 As delirium is a cognitive disorder, we further hypothesized that cognitive data (that are not included in the NSQIP calculation) could enhance the prediction of the surgical risk scores. The online surgical risk calculator built and copyrighted by the American College of Surgeons, National Surgical Quality Improvement Program (ACS NSQIP), may be ideal for delirium severity prediction as it includes several predisposing risk factors and the estimated magnitude of the precipitating event, the surgery.…”