Pretransplant endotrophin predicts delayed graft function after kidney transplantation

Abstract

Delayed graft function after kidney transplantation is common and increases morbidity and health care costs. There is evidence that endotrophin, a specific fragment of pro-collagen type VI, promotes the inflammatory response in kidney diseases. We tested the hypothesis that pretransplant endotrophin in kidney transplant recipients may be associated with the risk of delayed graft function. Pretransplant plasma endotrophin was assessed using an enzyme-linked immunosorbent assay in three independent cohorts with 806 kidney transplant recipients. The primary outcome was delayed graft function, i.e., the necessity of at least one dialysis session within one-week posttransplant. In the discovery cohort median pretransplant plasma endotrophin was higher in 32 recipients (12%) who showed delayed graft function when compared to 225 recipients without delayed graft function (58.4 ng/mL [IQR 33.4-69.0]; N = 32; vs. 39.5 ng/mL [IQR 30.6-54.5]; N = 225; P = 0.009). Multivariable logistic regression, fully adjusted for confounders showed, that pretransplant plasma endotrophin as a continuous variable was independently associated with delayed graft function in both validation cohorts, odds ratio 2.09 [95% CI 1.30-3.36] and 2.06 [95% CI 1.43-2.97]. Pretransplant plasma endotrophin, a potentially modifiable factor, was independently associated with increased risk of delayed graft function and may be a new avenue for therapeutic interventions.

Figure 1

Risk of delayed graft function in the two independent validation cohorts, “TxL” and “CONTEXT”. The graphs show the odds ratios and 95% confidence intervals using logistic regression to characterize the association between continuous pretransplant plasma endotrophin per increase in standard deviation and delayed graft function. Model 1 was unadjusted. Model 2 was adjusted for age, sex, race, and dialysis vintage (months). Model 3 was further cumulative adjusted for blood pressure and transplant type. Model 4 was further cumulative adjusted for pretransplant plasma creatinine. Model 5 was further cumulative adjusted for cold ischemic time. Adjustment for “CONTEXT” validation cohort did not include race, dialysis vintage (months), and blood pressure.

Figure 2

The graphs show the odds ratios and 95% confidence intervals (95% CI) for delayed raft function in the validation cohorts “TxL” and “CONTEXT”, using logistic regression to characterize the association between continuous pretransplant plasma endotrophin per increase in standard deviation and delayed graft function according to subgroup in the unadjusted analysis (Model 1). Subgroups included: Age < 60 years; Age ≥ 60 years; Male recipient; Female recipient.