Abstract 4347061: Impact of Preexisting Atrial Fibrillation on Mortality and Cardiovascular Outcomes in Kidney Transplant Recipients

Background: Atrial fibrillation (AFib) is common in kidney transplant recipients and may adversely affect outcomes. In the general population, AFib increases thromboembolism, bleeding, and cardiovascular risk, but its impact post-transplant is less defined. Research Question/Hypothesis: We hypothesized that pre-existing AFib is independently associated with adverse outcomes in kidney transplant recipients. Goals/Aims: To assess the long-term impact of pre-existing AFib on clinical outcomes in kidney transplant recipients over 5 years. Methods: Using the TriNetX Research Network (103 healthcare organizations), we identified adult kidney transplant recipients with (n=8,939) and without AFib (n=43,606), defined by ICD-10-CM and ICD-10-PCS codes. Propensity score matching (1:1) was done for demographics and comorbidities including heart failure, diabetes, hypertension, obesity, and coronary artery disease. Matched cohorts included 8,464 patients each. The index event was the transplant date. Outcomes were assessed over 5 years using Kaplan-Meier analysis, log-rank testing, hazard ratios (HR), risk ratios, odds ratios, and absolute risk differences. Primary outcomes included all-cause mortality, 3-point major adverse cardiovascular events (MACE), acute heart failure, graft rejection/failure, bleeding, hospital admission, kidney graft infections, and other infections. Results: After matching, AFib patients had higher 5-year all-cause mortality (21.0% vs. 10.4%; HR 2.23; 95% CI: 2.06–2.42; p<0.001), MACE (16.1% vs. 8.2%; HR 2.17; 95% CI: 1.96–2.40; p<0.001), acute heart failure (10.9% vs. 4.4%; HR 2.75; 95% CI: 2.42–3.13; p<0.001), and bleeding (6.8% vs. 3.5%; HR 2.13; 95% CI: 1.84–2.46; p<0.001). Infectious complications were also more common (54.8% vs. 47.8%; HR 1.27; 95% CI: 1.22–1.32; p<0.001). No significant differences were seen in graft failure/rejection (73.2% vs. 74.7%; HR 0.98; 95% CI: 0.95–1.02; p=0.271) or kidney graft infection (11.8% vs. 11.5%; HR 1.11; 95% CI: 1.02–1.21; p=0.022). Although cumulative hospital admission was slightly lower in AFib patients (84.1% vs. 86.2%), time to first admission was shorter (HR 0.91; 95% CI: 0.88–0.94; p<0.001). Conclusion: Pre-existing AFib is linked to significantly worse 5-year cardiovascular and infectious outcomes after kidney transplantation, though not to graft failure or rejection. These findings highlight the need for focused pre-/post-transplant care, including CV risk management and tailored anticoagulation.