Progression of mineral metabolism derangements in childhood chronic renal failure

Abstract

2 groups of children affected by different degrees of chronic renal failure (group 1, 55-36 ml/min/1.73 m2; group 2, 35-20 ml/min/1.73 m2 of creatinine clearance) due to tubulo-interstitial disease were studied for one year. The spontaneous evolution of altered mineral metabolism at different levels of glomerular filtration rate (GFR) was aimed at. Parathyroid hormone, vitamin D metabolites and bone mineral content were evaluated. At the end of the year, only a decrease of plasma levels of 1,25(OH)2D in group 1 and a worsening of all mineral metabolism parameters in group 2 were found. The results are consistent with the hypothesis that mineral metabolism derangements progress rapidly after a certain 'threshold' of endocrinologically active renal mass is reached. The falling of plasma 1,25(OH)2D levels below a still undetermined critical value might be assumed as an index of this threshold