Time to Readmission and Mortality Among Patients Undergoing Liver and Pancreatic Surgery.

BACKGROUND: The impact of time to readmission (TTR) on post-discharge mortality has not been well examined. We sought to define the impact of TTR on postoperative mortality after liver or pancreas surgery. METHODS: A retrospective cohort analysis of liver and pancreas surgical patients was conducted using 2013-2015 Medicare Provider Analysis and Review database. Patients were subdivided into TTR groups: 1-5 days, 6-15, 15-30, 31-60, 61-90, and no readmission. The association of index complication, readmission causes, TTR, and mortality was assessed. RESULTS: Among 18,177 patients, a total of 4485 (24.7%) patients were readmitted within 90 days of discharge. Major causes for readmission differed across TTR groups. Patients readmitted within 1-15 days were more likely to be readmitted for postoperative infection compared with patients who had a late readmission (1-5 days: 63.1% vs. 6-15 days: 65.0% vs. 61-90 days: 39.3%; P < 0.001). In contrast, causes of late readmissions were more likely related to gastrointestinal complications (1-5 days: 28.9% vs. 61-90 days: 39.7%; P < 0.001). Compared with no readmission, 180-day mortality was highest among patients readmitted within 16-30 days (aOR 3.60; 95% CI 2.94-4.41). Among patients with index complications, patients who were readmitted within 1-5 days had a higher risk-adjusted 180-day mortality than late readmission (1-5 days: 37.3% vs. 61-90 days: 27.1%) (P < 0.001). CONCLUSIONS: Among patients who were readmitted, the incidence of mortality increased with TTR up to 60 days after discharge yet decreased thereafter. The relation of TTR and mortality was particularly pronounced among those patients who had an index complication. Future efforts should consider TTR when identifying specific approaches to decrease readmission.