Prediction of Graft Rejection by Changing Serum Creatinine Patterns in Live Donor Kidney Transplants

Introduction: This study examines time vs. serum creatinine graphs after 2 weeks to 6 months of renal transplant with a view to define the earliest possible abnormal serum creatinine value which is likely to be due to rejection when combined with the other relevant clinical data. Methods: 35 biopsy proven ATIR cases from a single center, reported by an experienced consultant pathologist in the years of 2009, 2010 and 2011 were available. Their serial serum creatinine values done by the same laboratory were recorded. All the creatinine values were plotted against the time after transplant indicating the study parameters as in Fig 1.[Fig 1]At points of biopsy proven rejection, the rate of creatinine rise, time taken to peak value, the range of creatinine were compared with that of the baseline ranging over 15 days before the rejection spike of the same individual [Fig 1]. Results: The creatinine rises by 42 μmol/L within 20 days at a mean rate of 3.1 umol/L/day which was statistically significant compared to the baseline rate of 0.22umol/L/day of the same individual (p 0.01). The mean creatinine rising rate of > 1.6 umol/L/day for consecutive 3 creatinine readings taken within 12 days found to be 78% sensitive and 89% specific in predicting a rejection episode in this study group. 91% of graphs showed acceleration of the creatinine rising rate over a mean duration of 12 days giving a “concave” shape to the ascending limb of rejection spike. None of the baselines showed a “concave” shape. The mean delay between the first abnormal serum creatinine value and the 1st dose of methylprednisolone was 4.7 days. The first abnormal serum creatinine value was 14% above the base line creatinine value predicting rejection in the group. Except one case all the moderate to severe ATIR showed a spiky base line before the biopsy diagnosed spike of ATIR. They were occurring at a mean period of 30-40 days before the biopsy and have a creatinine elevation averaging 26umol/L. Conclusions: 1. Graphical analysis of serum creatinine vs. time graphs seem capable of predicting renal allograft rejection of moderate to severe degree occurring within first 2 weeks to 6 month of transplant approximately 4.5 days before it is suspected by noticing a higher creatinine value in this study group. 2. Features predictive of rejection in this study group were, >14% rise of serum creatinine from baseline >1.6 μmol/L/day creatinine rising rate over < 12 days Concaving rise in creatinine vs. time graph Appearance of small spikes