Does the KDIGO CKD risk stratification based on GFR and proteinuria predict kidney graft failure?

The 2012 Kidney Disease: Improving Global Outcomes (KDIGO) guidelines on chronic kidney disease (CKD) introduced risk classes for adverse outcome based on estimated glomerular filtration rate (eGFR) and albuminuria categories (low-LR, moderately-MR, high-HR, very high risk-VHR). We aimed to investigate if such risk stratification is suitable in kidney transplant (KTx) recipients. This single-center prospective study enrolled 231 prevalent KTx recipients [36 (34-48) years, 62 % male, eGFR 53.7 (50.9-56.4) mL/min]. The patients were stratified in risk classes in January 2011; clinical and laboratory data were collected every 6 months till June 2013. Individual slope of linear regression of all eGFR and time-averaged proteinuria (TAP) were computed. The composite endpoint was defined as > 30 % decline in eGFR from 6 months after KTx to June 2013, dialysis initiation or death. Fifty-one patients reached the endpoint. They were younger, more often female, donor specific anti-HLA antibodies positive, noncompliant and smokers. TAP was 4 time greater (p < 0.0001) and eGFR abruptly declined [eGFR slope: -3.17 (-4.13 to -2.21) vs. 0.81 (0.45-1.3) mL/min per year, p < 0.0001] in the endpoint group. At baseline: 36 % LR, 23 % MR, 23 % HR and 18 % VHR, without differences between the groups. In the binary logistic regression model, VHR as compared to the other risk classes was an independent risk factor for poorer outcome. The final model also included female gender, cardiovascular events, smoking, GFR slope and BK virus infection. Risk group stratification according to KDIGO guideline on CKD may prove useful in predicting graft outcome, but this should be confirmed in larger cohorts.