Risk factors and prognosis of late acute rejection in Chinese kidney transplant recipients.

AIM: Accumulating literature indicates that late acute rejection (LAR) after kidney transplantation portends an unfavourable prognosis. There are no data on the incidence of LAR in Asian subjects, or its risk factors and associated clinical outcomes. METHODS: We conducted a retrospective single-centre case-+control study to investigate the incidence, risk factors and prognosis of LAR in Chinese kidney transplant recipients. Subjects with or without LAR were matched for age, gender, era of transplantation, allograft type, and maintenance immunosuppression regimen. RESULTS: Thirty-two episodes of LAR occurred within an observation period of 12 years giving an incidence rate of 0.46 episodes per 1000 patient-years. Acute rejection within the first year after transplantation was associated with an increased risk of LAR (OR 3.59, P = 0.041). In patients receiving maintenance immunosuppression regimen with steroid, cyclosporin A (CsA) and mycophenolate or an m-TOR inhibitor, patients with LAR showed lower trough CsA levels prior to and at the time of rejection compared to Controls (86.0 ± 26.1 vs. 105.6 ± 13.3 µg/L, P = 0.049; and 75.7 ± 35.7 vs. 106.0 ± 20.5 µg/L, P = 0.032, respectively). Trough CsA level below 80 µg/L was associated with the development of LAR (OR 10.82, P = 0.032). Patients with LAR showed an inferior allograft survival (P < 0.001) while patient survival rates were similar (P = 0.122). CONCLUSIONS: Late acute rejection is uncommon in Chinese kidney transplant recipients but is associated with reduced allograft survival. Risk factors include acute rejection in the first post-transplant year and trough CsA level below 80 µg/L in patients on CsA-based maintenance immunosuppression. Minimization of immunosuppression in apparently stable kidney transplant recipients must be exercised with caution.

Minimal and optimal peritoneal Kt/V targets: results of an anuric peritoneal dialysis patient's survival analysis.

BACKGROUND: Residual renal clearance has been shown to be much more predictive of survival than peritoneal clearance. There has been little data to support a target level of peritoneal clearance. A retrospective study was therefore conducted to see how the peritoneal Kt/V had affected the survival of anuric patients in our center. METHODS: Over a period of 10 years, there were 150 peritoneal dialysis patients with documented anuria. Their survival was analyzed according to their baseline peritoneal Kt/V at the time of documentation of anuria and at the time of their latest altered peritoneal dialysis (PD) prescription (subsequent Kt/V). RESULTS: There were 90 females and 42 diabetics. The mean age and duration of dialysis were 57.7 +/- 14.7 and 44.1 +/- 31.3 months, respectively. The 2-year and 5-year survival rates were 88.7% and 66.7%, respectively. We found that patients with baseline peritoneal Kt/V below 1.67 had poorer survival after the documentation of anuria than those above [relative risk (RR) 1.985, P= 0.01], although the baseline Kt/V was not an independent risk factors in the whole group of patients. However, such effect was mainly observed in female patients. The survival was identical between those with Kt/V above or below 1.80 (P= 0.98). Among female patients, the group with baseline Kt/V 1.67 to 1.86 had the best survival, followed by those greater than 1.86 and lowest in those below 1.67 (P= 0.0016). For patients with baseline Kt/V below 1.80, those with subsequent Kt/V above 1.76 had better survival than those below (P= 0.033). CONCLUSION: Our data suggested that a negative effect of peritoneal Kt/V on survival is apparent at a level below 1.67 and there exists a limit of its effect at around 1.80. We suggested a minimal Kt/V target of 1.70 and an optimal target at 1.80 in anuric patients based on survival data. Prospective randomized study is required to confirm this finding.