Longitudinal Assessment of Serum Creatinine Levels on Graft Survival After Renal Transplantation: Joint Modeling Approach

BACKGROUND: Chronic kidney disease (CKD) is a major public health problem. The eventual outcome of CKD is end-stage renal disease (ESRD). Early diagnosis and proper management play an important role in preventing CKD progression to ESRD. Dialysis and kidney transplantation are the only treatment options available for patients suffering from ESRD. OBJECTIVES: This study was designed to investigate the etiological role of recipient and donor characteristics on serum creatinine changes within the follow-up period, graft failure risk, and the impact of longitudinal serum creatinine levels on graft survival after renal transplantation. PATIENTS AND METHODS: This study was carried out at the department of nephrology, Baqiyatallah hospital, Baqiyatallah University, Tehran, Iran, between April 2005 and December 2008. During that time period, 461 patients who had undergone renal transplantation were entered in the current study. Time to graft loss and serum creatinine levels at each visit were the primary data gathered for the study. A joint modeling of survival and longitudinal nonsurvival data was used to assess the association between the two processes and investigate the influential factors. RESULTS: Median follow-up time was 6.80 months. A linear decreasing trend in serum creatinine level over time was found (P < 0.001). The results showed a positive correlation between serum creatinine levels and risk of graft failure (P < 0.001). CONCLUSIONS: The major finding of this study is that one unit increase in serum creatinine level suggests an increased risk of graft failure of up to four times.