Association of Preoperative Frailty and Postoperative Outcomes in Older Adults Undergoing Major Cardiac Procedures: A Systematic Review and Meta-Analysis
Bibliographic record
Abstract
BACKGROUND: Frailty, characterized by reduced physiological resilience, is a pivotal risk factor in older adults undergoing major cardiac procedures. Although previous analyses have linked frailty to adverse surgical outcomes, knowledge gaps persist due to methodological inconsistency across frailty tools and limited synthesis of complications such as delirium, infection, and renal dysfunction. The objective of this systematic review and meta-analysis is to determine the prevalence of preoperative frailty in older adults undergoing major cardiac procedures, and assess its association with postoperative outcomes, including cardiac, respiratory, renal, infectious, stroke, and bleeding complications, postoperative delirium, hospital and intensive care unit (ICU) length of stay, nonhome discharge, hospital readmission, and both 30-day and 1-year mortality. METHODS: A prespecified protocol was registered with PROSPERO (CRD#42024574916), following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. MEDLINE, Embase, and Cochrane databases were searched for English-language studies of patients undergoing major cardiac procedures, including coronary artery bypass grafting (CABG), aortic or mitral valve replacement or repair, transcatheter aortic valve replacement (TAVR), or combined procedures. Validated frailty instruments (eg, Fried Frailty Phenotype, Clinical Frailty Scale) were required to determine preoperative frailty, along with reporting at least 1 postoperative outcome. Noncardiac surgeries, minor procedures, case reports, and reviews were excluded. Random-effects meta-analyses generated odds ratio (OR) or standardized mean difference (SMD) values with 95% confidence intervals (CI). RESULTS: Nineteen studies (n = 11,667; mean ± SD age 71.9 ± 8.1 years, 28% female) met inclusion criteria, spanning North America, Europe, Asia, and Oceania. The overall prevalence of preoperative frailty was 16.8%. Frailty was significantly associated with delirium (OR, 4.11; 95% confidence interval [CI], 2.00-8.45; P <.001), infection (OR, 3.72; 95% CI, 2.27-6.12; P <.001), renal complications (OR, 2.72; 95% CI, 2.05-3.60; P <.001), and extended hospital (SMD, 0.69 ; 95% CI, 0.35-1.02; P <.001) and ICU (SMD, 0.72; 95% CI, 0.51-0.94; P <.001) stays. Frailty increased the odds of 30-day (OR, 3.58; 95% CI, 2.16-5.93; P <.001) and 1-year (OR, 2.25; 95% CI, 1.56-3.25; P <.001) mortality. CONCLUSIONS: Frailty affects nearly 1 in 5 older adults requiring major cardiac procedures. Frailty was significantly associated with adverse postoperative outcomes, including delirium, infections, renal complications, extended length of stay, and mortality. As frailty is potentially modifiable, targeted strategies-such as prehabilitation, nutritional optimization, and enhanced perioperative monitoring-may improve outcomes. Incorporating routine frailty screening into standard preoperative practice allows for earlier identification of high-risk patients, efficient resource allocation, and perioperative care planning.
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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 | 0.012 | 0.032 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.016 | 0.039 |
| Bibliometrics | 0.006 | 0.007 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| 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".