Abstract
OBJECTIVE: The association between chronic kidney disease and adverse outcomes after coronary artery bypass grafting is well established; in contrast, the association between chronic kidney disease and readmission has been less thoroughly investigated. We hypothesized that patients at higher chronic kidney disease stages have greater risk of readmission, poorer operative outcomes, and greater hospitalization cost. METHODS: Using the 2016-2018 Nationwide Readmissions Database, we identified 519,387 patients who underwent isolated coronary artery bypass grafting. Patients were stratified by chronic kidney disease stage based on International Classification of Diseases 10(th) Revision classification. Multivariable logistic regression was used to assess risk factors for in-hospital mortality and 90-day readmission. RESULTS: Hospital readmission, in-hospital mortality, and cost progressively increased with worsening chronic kidney disease stage; patients with end-stage renal disease had the highest in-hospital mortality rate (7.2%), hospitalization costs ($59,616) (P < .001), and 90-day readmission rate (40%) (P < .001). Chronic kidney disease stage greater than 3 was associated with in-hospital mortality (odds ratio, 1.56, 95% confidence interval, 1.40-1.73; P < .001) and 90-day readmission (odds ratio, 1.66, 95% confidence interval, 1.56-1.76; P < .001). At 30 days after discharge, new-onset dialysis dependence was more frequent in patients readmitted with chronic kidney disease 4 to 5 (8.9%; n = 1495) than in patients with chronic kidney disease 1 to 3 (1.4%; n = 8623) and patients without chronic kidney disease (0.3%; n = 38,885). At 90 days after discharge, dialysis dependence increased to 11.1% (n = 1916) in readmitted patients with chronic kidney disease 4 to 5 but remained stable for patients with chronic kidney disease 1 to 3 (1.4%; n = 10,907) and patients without chronic kidney disease (0.3%; n = 50,200). CONCLUSIONS: Chronic kidney disease stage is strongly associated with mortality, new-onset dialysis dependence, readmission, and higher cost after coronary artery bypass grafting. Patients with chronic kidney disease 4 and 5 and patients with end-stage renal disease are readmitted at the highest rates. Although further research is needed, a targeted approach may reduce costly readmissions and improve outcomes after coronary artery bypass grafting in patients with chronic kidney disease.