Predicting progression in IgA nephropathy

Immunoglobulin A (IgA) nephropathy is one of the most common primary types of glomerulonephritis to progress to end-stage renal disease. Its variable and often long natural history makes it difficult to predict outcome. We in vestigated the association of the rate of renal function decline based on t he slope of creatinine clearance over time with demographic, clinical, labo ratory, and histological data from 298 patients with biopsy-proven IgA neph ropathy with a mean follow-up of 70 months. Using univariate analysis, urin ary protein excretion at baseline and Lee pathological grading, as well as mean arterial pressure (MAP) and urinary protein excretion during follow-up , were associated with the rate of deterioration in renal function. Of thes e, only MAP and urinary protein excretion during follow-up were identified as independent factors by multiple linear regression analysis. The combinat ion of best accuracy of prediction and shortest observation time using thes e two parameters was reached between the second and third years of follow-u p. A semiquantitative method of estimating the rate of progression by using these factors was developed. These results indicate that MAP and severity of proteinuria over time are the most important prognostic indicators of Ig A nephropathy. The potential relevance of the algorithm In patient manageme nt is shown. (C) 2001 by the National Kidney Foundation, Inc.