Risk factors for late renal allograft dysfunction: effects of baseline glomerular size.

BACKGROUND: Both alloantigen dependent and alloantigen independent factors contribute to late allograft dysfunction. Among the latter, the importance of the mass of the donor kidney is an issue of interest. We hypothesized that glomerular hypertrophy is a risk factor for deterioration of allograft function. The goal of this study was to examine the role of glomerular size in predicting late allograft dysfunction.

METHODS: All baseline graft biopsies between 1990 and 1998 were reviewed and sections containing at least 15 glomeruli were selected for morphometric analyses. Glomerular size was measured using the maximal profile area (MPA) method. Linear correlations between creatinine clearance (Ccr) and variables were evaluated. Covariates that tended to correlate with Ccr on univariate analysis (p < 0.2) were examined using multivariate analysis to determine the covariates associated with Ccr at 6 months (M) and 1, 2, 3, 4 years (yrs) after transplantation.

RESULTS: Eighty-six patients were enrolled. Donor age, MPA, baseline Ccr, percent of global glomerulosclerosis (GS%), cyclosporin nephrotoxicity, cold ischemic time(CIT) and episodes of rejection were significantly correlated with interval Ccr in univariate analyses. MPA was a significant covariate at 6M, 1 yr, 3 yrs and 4 yrs. Other covariates significantly associated with interval Ccr included GS%, baseline Ccr, CIT and number of acute rejection episodes.

CONCLUSIONS: Glomerular size in baseline biopsies is predictive of late allograft function, and the presence of hypertrophied glomeruli combined with other factors contributes to chronic renal allograft dysfunction.