Drivers of Readmissions in Vascular Surgery Patients

Abstract

Readmissions are frequent in vascular surgery patients, but it is not clear which factors are the drivers of readmissions. Specifically, the relative contributions of patient comorbidities vs postoperative complications are unknown. We sought to study the potential drivers of readmission and create a model for predicting the risk of readmission in vascular patients. The 2012 to 2013 American College of Surgeons National Quality Improvement Program data set was queried for unplanned readmissions in vascular patients. Bivariable and multivariable risk adjustment analyses were used to model the relative contributions of patient comorbidities, operative factors, and postoperative complications for readmission. The unplanned readmission rate was 9.3%. The preoperative model based on patient comorbidities predicted readmission risk with a low C index of 0.666; the top five predictors were American Society of Anesthesiologists class, preoperative open wound, inpatient operation, dialysis dependence, and diabetes mellitus. The postoperative model that included postoperative complications predicted readmission risk better (C index, 0.778); postoperative complications were the most significant predictor of readmission, overpowering patient comorbidities. Importantly, postoperative complications identified prior to discharge from the hospital were not a strong predictor of readmission because the model using predischarge postoperative complications had a similar C index to our preoperative model (0.681). However, the inclusion of complications identified after discharge appreciably improved the predictive power of the model (C index, 0.778). The top five predictors of readmission in the final model based on comorbidities and postoperative complications were postdischarge deep space infection, superficial wound infection, pneumonia, myocardial infection, and sepsis. Readmissions in vascular surgery patients are mainly driven by postoperative complications identified after discharge. Thus, efforts to reduce vascular readmissions based on inpatient data may prove ineffective. Our study suggests interventions to reduce vascular readmissions should focus on prompt identification of modifiable postdischarge complications.