RESUMO
OBJECTIVE: To develop our own procedures, allowing for a quick evaluation of glomerular basement membrane (GBM) thickness and to present a statistical classification of thin basement membrane disease (TBMD), minimal change disease (MCD), and IgA nephropathy (IgAN) cases. STUDY DESIGN: Measurements were carried out with the aid of the original software for semiautomatic image analysis on biopsies from 31 children with TBMD, 51 with MCD, and 10 with IgAN. RESULTS: The strongest statistically significant dependence between GBM thickness and age was observed in children with MCD below 5 years of age. There was no significant dependence between GBM thickness and age among patients with TBMD. The values of all analyzed parameters characterizing GBM thickness distribution in children with TBMD were significantly lower than those in patients with MCD and IgAN. A slight, statistically significant increase of some parameters was noted in children with IgAN in contrast to patients with MCD. The multivariate logistic regression model with three independent variables--quartile 1, quartile 3, and percentile 30--proved to be the most appropriate in differentiating between patients with TBMD and children with MCD or IgAN. The model allowed for correctly classifying 96.8% of patients with TBMD (30 of 31 children) and 98.4% patients from the MCD and IgAN groups (60 of 61 children). We failed to construct a similarly appropriate model for differentiating between patients with MCD and IgAN. CONCLUSION: The introduction of morphometric and statistical methods to routine nephropathologic diagnostics represents true progress in very precise and quick assessment of GBM thickness.
