Abstract

COSTA, Rui et al. Acute rejection during the first six-months after transplantation: temporal trends regarding risk factors and effects on graft and patient survival. Port J Nephrol Hypert [online]. 2014, vol.28, n.1, pp.40-48. ISSN 0872-0169.

Objective: To determine risk factors for acute rejection in the first 6 months post- transplant and their effect on death-censored graft and patient survival in the  990-1999 and 2000-2009 periods. Patients and Methods: Retrospective analysis of acute rejection episodes was performed separately in two periods: 1990-1999 and 2000-2009. Multivariate logistic regression analysis was performed in order to identify risk factors for acute rejection. Death-censored graft and patient survival comparison between patients with or without acute rejection occurrence was performed by Kaplan-Meier analysis. Multivariate Cox regression analysis identified independent predictors for death-censored graft and patient survival, assuming the following model: acute rejection, patient’s age (< 40 vs. ≥ 40 years) and gender, time on haemodialysis / peritoneal dialysis (< 36 vs. ≥ 36 months), live vs. deceased donor (only after the year 2000), HLA mismatches (0-3 vs. 4-6), PRA (≤ 15 vs. > 15%), number of previous kidney transplants (< 2 vs. ≥ 2), status of hepatitis B/C, donor´s age (< 38 vs. ≥ 38 years) and gender, delayed graft function (DGF), ATG use in induction immunosuppression (IS), MMF or Tacrolimus use in induction / maintenance IS (after 2000). Results: A total of 1299 kidney transplants were analyzed. Acute rejection was more frequently diagnosed in the 1990s (26.2% vs. 11.1%, p < 0.001). Over this period, ATG non-use (OR 1.88, p = 0.025) and patients’ age < 40 years (OR 2.39, p = 0.001) were risk factors for AR while, after 2000, DGF (OR 1.895, p = 0.046) and PRA > 15% (OR 3.519, p = 0.001) were identified. Five years death-censored graft survival was lower in AR cases in the 1990s (81% vs. 94%, p < 0.001) and after 2000 (81% vs. 91%, log rank p = 0.004). Independent predictors for worse death-censored graft survival in 1990-1999 patients were AR (HR 2,436, p < 0.001), patient´s age < 40 years (HR 1.984, p = 0.002) and donor´s age ≥ 38 years (HR 1.961, p = 0.002), while after 2000, DGF (HR 3.247, p < 0.001) and donor´s age ≥ 38 years (HR 2.32, p = 0.017) were identified. No difference was found at five-year patient survival in both groups. Only hepatitis B/C (HR 1.714, p = 0.023) was identified as an independent predictor for patient death in the 1990-1999 period, while after 2000, retransplantation (HR 2,718, p = 0.049) and AR (HR 2,619, p = 0.023) were determinant. Conclusion: After the year 2000, AR was no longer an independent predictor for poor graft survival. Inversely, AR began to play a deleterious effect on patient survival. Advances on immunosuppressive drugs allowed the increase of kidney transplant on hypersensitized patients, with improvement of graft survival in those patients but also with a possible deleterious effect on patient survival.

Keywords : acute rejection; kidney transplant; predictors; survival.

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