Preoperative Risk Assessment for Delirium After Noncardiac Surgery: A Systematic Review
Bibliographic record
Abstract
Delirium is a common postoperative complication in older adults associated with adverse events including functional decline, longer lengths of stay, and risk of institutionalization. The purpose of this article is to systematically review preoperative risk factors associated with delirium following noncardiac surgery. A medical literature search was conducted using several bibliographic databases (PubMed, CINAHL, Cochrane, PsychInfo), supplemented by a manual search of the references of retrieved articles. Studies were retained for review after meeting strict inclusion criteria that included only operative patients with incident postoperative delirium diagnosed prospectively using criteria derived from the Diagnostic and Statistical Manual of Mental Disorders Third or Fourth Edition. Quantitative analyses included significance testing, homogeneity testing, and effect-size pooling. Twenty-five articles were included for review. The incidence of delirium ranged from 5.1% to 52.2%, with greater rates after hip fracture and aortic surgeries. This review found two scales, a clinical prediction rule, and a delirium risk classification system that were validated in other operative settings. Individual risk factor analysis suggested that cognitive impairment, older age, functional impairment, sensory impairment, depression, preoperative psychotropic drug use, psychopathological symptoms, institutional residence, and greater comorbidity were associated with postoperative delirium. Of the risk factors examined, evidence was most robust for an association between delirium and cognitive impairment or psychotropic drug use, with moderate effect sizes for both. Missing data and measurement differences did not allow for inferences to be made about other risk factors. Effect-size pooling supports the concept that delirium is a heterogeneous disorder with multiple risk factors. More research is needed to better identify patients at risk for postoperative delirium and to develop preventive strategies.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.028 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.006 | 0.007 |
| Bibliometrics | 0.009 | 0.008 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".