Association of Preoperative Frailty and Postoperative Outcomes in Older Adults Undergoing Major Cardiac Procedures: A Systematic Review and Meta-Analysis

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.