An age-independent hospital record-based frailty score correlates with adverse outcomes after heart surgery and increased health care costs

Background: Globally, an increasing number of vulnerable or frail patients are undergoing cardiac surgery. However, large-scale frailty data are often limited by the need for time-consuming frailty assessments. This study aimed to (1) create a retrospective registry-based frailty score (FS), (2) determine its effect on outcomes and age, and (3) health care costs. Methods: Retrospective data were obtained from the New Brunswick Heart Centre registry for all cardiac surgery patients between 2012 and 2017. A 20-point FS was created using available binary risk variables. The primary outcomes of interest most relevant to vulnerable patients were prolonged hospitalization, failure to be discharged home, and hospitalization bed cost. Composite outcome of prolonged hospitalization (>8 days) and/or non-home discharge were analyzed using multivariate analysis. Results: A total of 3463 patients (mean age, 66 ± 10 years) were included in the final analysis. Tercile-based FSs were: low (0-4; n = 856), medium (5-7; n = 1709), high (≥8; n = 898). In unadjusted data, frail patients were older with more comorbidities. High FS patients had greater risks of prolonged hospitalization (median 7 vs 5 days; P < .001), lower home-discharge rates (51% vs 83%; P < .001), higher 30-day readmission rates (18% vs 10%; P < .001), and increased 30-day mortality rates (≤0.7% [low], >0.7% to ≤1.2% [medium], and >1.2% to 4.8% [high]; P < .001). After statistical adjustment, the FS was an independent predictor of composite outcome (odds ratio, 1.3: 95% CI, 1.26-1.35), and increased hospital bed costs. Conclusions: A registry-based FS can be used to identify vulnerable or frail patients undergoing cardiac surgery and was associated with poor outcomes independent of age. This highlights that although frailty defined by increased vulnerability is often associated with older age, it is not a surrogate for aging, thereby having important implications in reducing health system costs and efforts to provide streamlined care to the most vulnerable.