Association between aortic calcification, cardiovascular events and mortality in kidney and pancreas-kidney transplant recipients

Background: Cardiovascular (CV) disease is the leading cause of death in kidney and simultaneous pancreas-kidney (SPK) transplant recipients. Assessing abdominal aortic calcification (AAC), using lateral spine x-rays and the Kaupilla 24-point AAC (0–24) score, may identify transplant recipients at higher CV risk. Methods: Between the years 2000 and 2015, 413 kidney and 213 SPK first transplant recipients were scored for AAC at time of transplant and then followed for CV events (coronary heart, cerebrovascular, or peripheral vascular disease), graft-loss, and all-cause mortality. Results: The mean age was 44 ± 12 years (SD) with 275 (44%) having AAC (26% moderate: 1–7 and 18% high: ≥8). After a median of 65 months (IQR 29–107 months), 46 recipients experienced CV events, 59 died, and 80 suffered graft loss. For each point increase in AAC, the unadjusted hazard ratios (HR) for CV events and mortality were 1.11 (95% CI 1.07–1.15) and 1.11 (1.08–1.15). These were similar after adjusting for age, gender, smoking, transplant type, dialysis vintage, and diabetes: aHR 1.07 (95% CI 1.02–1.12) and 1.09 (1.04–1.13). For recipients with high versus no AAC, the unadjusted and fully-adjusted HRs for CV events were 5.90 (2.90–12.02) and 3.51 (1.54–8.00), for deaths 5.39 (3.00–9.68) and 3.38 (1.71–6.70), and for graft loss 1.30 (0.75–2.28) and 1.94 (1.04–3.27) in age and smoking history-adjusted analyses. Conclusion: Kidney and SPK transplant recipients with high AAC have 3-fold higher CV and mortality risk and poorer graft outcomes than recipients without AAC. AAC scoring may be useful in assessing and targeted risk-lowering strategies.