Abstract 232: The Society of Thoracic Surgeons Mortality Risk Score Predicts 30-Day Hospital Readmissions

Abstract

Introduction- Readmissions are associated with poor quality of care and unnecessary healthcare costs. Hence, minimizing unplanned hospital readmissions has become a priority among health care professionals and policymakers. Accurately predicting the risk for readmission could guide the efficient delivery of timely transitional care. Recently, the Society of Thoracic Surgeons (STS) risk score was used to predict hospital charges and resource use after aortic valve replacement. We hypothesize that the STS predicted mortality risk score could accurately discriminate which of the patients will be readmitted within 30 days. Methods- Clinical data from patients undergoing cardiac surgical procedures at four Intermountain hospitals over a three year period (1/2009 - 12/2011) were analyzed. The main outcome was 30-day all-cause acute care readmissions. The predicted mortality risk score was ascertained using the STS risk algorithm and categorized into tertiles based on the population distribution. Odds ratio (OR) estimates and 95% confidence intervals (CI) were obtained from logistic regression. Results- The overall mean STS predicted mortality risk score was 2.02 (SD = 3.12). The overall unadjusted readmission rate among the cardiac surgical cohort was 11.04%. Patients with a moderate mortality risk score (M = 1.13, SD = 0.28) were more likely (OR=1.45; 95% CI 1.00 - 2.08) to be readmitted than patients with a low mortality risk score (M = 0.46, SD = 0.14). Similarly, patients with a high mortality risk score (M = 4.48, SD = 4.47) had higher odds of readmission (OR=2.51; 95% CI 1.79 - 3.52). Conclusions- Our results suggest that the STS mortality risk score predicts 30-day all cause acute care readmissions. More research is warranted to investigate its clinical usefulness.