Frailty and pre-frailty in cardiac surgery: a systematic review and meta-analysis of 66,448 patients

Background The burden of frailty on cardiac surgical outcomes is incompletely understood. Here we perform a systematic review and meta-analysis of studies comparing frail versus pre-frail versus non-frail patients following cardiac surgery. Methods We searched MEDLINE and EMBASE databases until July 2018 for studies comparing cardiac surgery outcomes in "frail", "pre-frail" and "non-frail" patients. Data was extracted in duplicate. Primary outcome was operative mortality. Results There were 19 observational studies with 66,448 patients. Frail patients were more likely female (risk ratio [RR]1.7; 95%CI:1.5-1.9), older (mean difference: 2.4; 95%CI:1.3-3.5 years older) with greater comorbidities and higher STS-PROM. Frailty (RR2.35; 95%CI:1.57-3.51; p < 0.0001) and pre-frailty (RR2.03; 95%CI:1.52-2.70; p < 0.00001) were associated with increased operative mortality compared with non-frail patients. Frailty was also associated with greater risk of prolonged hospital stay (RR1.83; 95%CI:1.61-2.08; p < 0.0001) and intermediate care facility discharge (RR2.71; 95%CI:1.45-5.05; p = 0.002). Frail (Hazard Ratio [HR]3.27; 95%CI:1.93-5.55; p < 0.0001) and pre-frail patients (HR2.30; 95%CI:1.29-4.09; p = 0.005) had worse mid-term mortality (median follow-up 1 years [range 0.5-4 years]). After adjustment for baseline imbalances, frailty was still associated with greater operative mortality (odds ratio [OR]1.97; 95%CI:1.51-2.57; p < 0.00001), intermediate care facility discharge (OR4.61; 95%CI:2.78-7.66; p < 0.00001) and midterm mortality (HR1.37; 95%CI:1.03-1.83; p = 0.03). Conclusion In patients undergoing cardiac surgery, frailty and pre-frailty were associated with 2-fold and 1.5-fold greater adjusted operative mortality, respectively, greater adjusted perioperative complications and frailty was associated with almost 5-fold risk of non-home discharge.