Prevalence and risk factors of frailty among cardiac surgery patients: a systematic review and meta-analysis

Frailty is common among cardiac surgery patients and is associated with poor outcomes. Previous reviews have been limited by outdated searches, narrow surgical populations, or reliance on a single assessment tool. This study aimed to estimate the prevalence of frailty and identify associated risk factors in patients undergoing cardiac surgery. We searched MEDLINE, Embase, Cochrane Library, CINAHL, Web of Science, and Scopus, from inception to March 1, 2025. Eligible studies reporting frailty prevalence in patients undergoing CABG, valvular surgery, or heart transplantation were included. Intervention studies, reviews, editorials, case series, and transcatheter procedures were excluded. Risk of bias was assessed by the Joanna Briggs Institute checklist. Random-effects meta-analysis provided pooled prevalence and risk factor estimates. Seventy-eight studies (<i>n</i> = 6,613,392) were included. The pooled frailty prevalence was 30.2% (95% CI: 28.3–32.0) with high heterogeneity (I² = 99.99%, <i>p</i> &lt; .001). Key sociodemographic associations were increasing age (SMD = 0.29 [0.18, 0.40]) and male sex (OR = 0.55 [0.46, 0.65]). Lower hemoglobin (SMD = −0.62 [−0.82, −0.42]) and albumin (SMD = −0.48 [−0.68, −0.28]) were significant laboratory correlates; NYHA class IV (OR = 6.29 [4.07, 9.71]) and higher EuroSCORE II (SMD = 0.52 [0.37, 0.68]) were strong clinical predictors. Comorbidities—including atrial fibrillation, liver, pulmonary, renal, neurological dysfunction, and diabetes—were also associated with frailty. Frailty impacts nearly one-third of cardiac surgery patients and is associated with several, partly modifiable factors. Preoperative screening using validated tools and focused management of modifiable risks could enhance perioperative outcomes. PROSPERO registration number: CRD420251015280