Thirty-day Hospital Readmissions Following Cardiac Surgery are Associated With Mortality and Subsequent Readmission.

The aim of the current study was to assess the impact of hospital readmissions within 30-days of discharge, on long-term postoperative outcomes. All patients who underwent cardiac surgery from 2011 - 2018 were included. Patients who had transcatheter procedures, VAD, and transplant were excluded. Inverse probability of treatment weighting (IPTW) propensity scoring was used for population risk adjustment. Multivariable analysis was performed to identify association with long-term mortality and readmission. The total risk adjusted (propensity scoring with IPTW) patient population consisted of 14,538 patients divided into those who were not readmitted in 30-days (nonreadmitted) (n = 12,627) and patients who were readmitted within 30-days (30-day readmitted) (n = 1911). Following IPTW, all baseline characteristics and postoperative complications were equivalent between cohorts (SMD <0.10). Patients who required intraoperative [OR 1.178 (1.05, 1.32); P = 0.006] and postoperative [1.32 (1.18, 1.48); P < 0.001] blood transfusions were at greater risk for 30-day readmission. Median follow-up period was 4.19 years (2.45 - 6.10). The 30-day readmission cohort had a significantly higher mortality risk during early (6 months) follow-up [HR 2.49 (2.01-3.10); P < 0.001] and late (60 months) follow-up [HR 1.30 (1.16-1.47); P < 0.001]. After risk adjustment, the 30-day readmission cohort was significantly associated with increased mortality over the study follow-up period [HR 1.62 (1.48, 1.78); P < 0.001]. 30-day readmissions were an independent predictor of subsequent long-term hospital readmission [HR 1.61 (1.50, 1.73); P < 0.001]. Patients who require 30-day readmissions following cardiac surgery are at increased risk of long-term mortality and repeat readmissions. Early postoperative hospital readmission may be a marker for worse long-term outcomes in cardiac surgery.