J. E. Tooley1, D. D. Bohl1, S. Kulkarni1, M. I. Rodriguez-Davalos1, S. Emre1, D. C. Mulligan1, P. S. Yoo1 1Yale University School Of Medicine,Transplant Surgery,New Haven, CT, USA
Introduction: We investigated the national trend in prevalence of kidney transplants in patients receiving coronary artery bypass grafts (CABG) and determined if these patients have worse outcomes compared to the national average.
Methods: This was a retrospective cohort study using the 2004 – 2011 Nationwide Inpatient Sample (NIS) – the largest inpatient database in the United States, which documents 8 million hospitalizations annually. All patients receiving CABG during their hospitalization were identified by ICD-9 procedure code. We then identified patients with history of kidney transplant by ICD-9 diagnosis codes. Baseline differences in age, sex, and comorbidities between CABG patients with a history of kidney transplant compared to all other patients receiving CABG were identified. The primary outcome measure was in-hospital all-cause mortality. Secondary outcomes included length of stay and total hospitalization charge. Comparisons were made using bivariate analysis and multivariate analysis correcting for identified baseline differences.
Results:The percentage of CABG patients with kidney transplants has increased from 0.10% in 2004 to 0.20% in 2011 (p=0.002). Kidney transplant patients receiving CABG were younger (59.1±9.9 vs. 66.0±10.9, p=0.002) and more commonly female (33.8% vs. 28.4%, p=0.002) compared to other CABG patients. Charlson comorbidity index scores did not differ between groups. In hospital all-cause mortality was higher among kidney transplant patients receiving CABG than the remainder of the CABG cohort (4.83% vs. 2.79%, p = 0.001). On average, kidney transplant patients stayed in the hospital an extra 1.74 days (95% Confidence Interval (CI) 1.12 – 2.36, p <0.001) and had an increase in total charge of hospitalization by $22,829 (95% CI $14,946 – $30,711).
Conclusion:The percentage of CABG patients with kidney transplants doubled between 2004 and 2011. These patients have increased mortality, increased length of stay, and increased hospitalization charges compared to other patients receiving CABG. These findings warrant further investigation into the causes for disparities in CABG outcomes in kidney transplant patients.
