VALIDATION OF A PREDICTIVE MODEL OF IDIOPATHIC MEMBRANOUS NEPHROPATHY- ITS CLINICAL AND RESEARCH IMPLICATIONS

Although a number of factors have consistently correlated with progres sion to chronic renal insufficiency (CRI) in idiopathic membranous glo merulonephropathy (IMGN), they appear late. are not quantitative in na ture and have nut been validated. We have determined that the highest sustained six-month period of proteinuria is an important predictor of progression. Using multiple logistic modelling, the only additional p rognostic variables of importance in 184 Canadian patients were the in itial creatinine clearance and the rate of change in function over thi s six-month interval. Independent data from Italy (101 patients) and F inland (78 patients) were obtained for comparison. Sensitivity, specif icity, negative and positive predictive values and overall accuracy, a s well as Pearson's goodness-of-fit and Harrell's ''C'' statistic were used to assess the fits of the model. Accuracy of prediction was grea ter than or equal to 85% in all three countries. Pearson's Chi-square goodness-of-fit showed good agreement across the spectrum and Harrell' s ''C'' statistic was greater than or equal to 90%. Therefore, a predi ctive, semiquantitative algorithm in IMGN has been validated. Its rele vance in patient management and in clinical trials is illustrated.