Association of serum activin levels with allograft outcomes in patients with kidney transplant: Results from the KNOW-KT.

INTRODUCTION: Serum activin A has been reported to contribute to vascular calcification and kidney fibrosis in chronic kidney disease. We aimed to investigate whether higher serum activin levels were associated with poor allograft outcomes in patients with kidney transplants (KT).

METHODS: A total of 860 KT patients from KNOW-KT (KoreaN cohort study for Outcome in patients With Kidney Transplantation) were analyzed. We measured serum activin levels at pre-KT and 1 year after KT. The primary outcome was the composite of a ≥ 50% decline in eGFR and graft failure. Multivariable cause-specific hazard model was used to analyze association of 1-year activin levels with the primary outcome. The secondary outcome was coronary artery calcification score (CACS) at 5 years after KT.

RESULTS: During the median follow-up of 6.7 years, the primary outcome occurred in 109 (12.7%) patients. The serum activin levels at 1 year were significantly lower than those at pre-KT (488.2 ± 247.3 vs. 704.0 ± 349.6). When patients were grouped based on the median activin level at 1 year, the high-activin group had a 1.91-fold higher risk (95% CI, 1.25-2.91) for the primary outcome compared to the low-activin group. A one standard deviation increase in activin levels as a continuous variable was associated with a 1.36-fold higher risk (95% CI, 1.16-1.60) for the primary outcome. Moreover, high activin levels were significantly associated with 1.56-fold higher CACS (95% CI, 1.12-2.18).

CONCLUSION: Post-transplant activin levels were independently associated with allograft functions as well as coronary artery calcification in kidney transplant patients.