Postdischarge Occurrences After Colorectal Surgery Happen Early and Are Associated With Dramatically Increased Rates of Readmission

BACKGROUND: Postoperative occurrences have been associated with an increased risk of readmission, yet these occurrences and their timing have not been well characterized. OBJECTIVE: We sought to analyze patients undergoing colorectal surgery as a model for general surgical readmissions. DESIGN: In a retrospective analysis, the impact of a postoperative occurrence on readmission was examined in a multivariable model with adjustment for potential confounders. The timing and type of postoperative occurrence were further characterized. SETTINGS: This study was conducted at a tertiary care hospital. PATIENTS: Patients undergoing colorectal surgery in the American College of Surgeons National Surgical Quality Improvement Program database (fiscal year 2011-2012) were analyzed. MAIN OUTCOME MEASURES: The main outcome measure was admission within 30 days of operation. RESULTS: A total of 54,823 patients undergoing colorectal surgery were identified, with 24% of patients experiencing a postoperative occurrence, and 12% of patients readmitted. The readmission rate in those who experienced an occurrence was 30% compared with 6% in those without an occurrence (p < 0.0001). After an occurrence during the index admission, the readmission rate was 18% compared with 57% if the occurrence happened postdischarge (p < 0.0001). In a multivariable analysis, postdischarge occurrence (risk ratio, 7.5 [ 95% CI, 7.3-7.8]) was associated with the largest risk of readmission. The median time to postdischarge occurrence was 8 days for organ space infection and wound complication and 7 days for sepsis. By day 14 postdischarge, 74% of organ space infections, 79% of wound complications, and 81% of sepsis had already occurred. LIMITATIONS: This analysis was limited to the variables available in the American College of Surgeons National Surgical Quality Improvement Program. Most significantly, readmission is captured for 30 days postoperatively rather than for 30 days postdischarge. CONCLUSIONS: Readmission occurs frequently (12%) after colorectal surgery and is strongly associated with a postdischarge occurrence. The most frequent postdischarge occurrences are infectious in nature and happen early postdischarge. The majority of postdischarge occurrences have already occurred by day 14, a standard time for the postoperative appointment.