Decreased renal function in association with administration of 1,25-dihydroxyvitamin D3 to patients with stable, advanced renal failure.

A controlled study of the effects of 1,25-dihydroxycholecalciferol (1,25[OH]2D3) and vitamin D3 (D3) was performed in 18 non-dialyzed patients with chronic renal failure (CRF) (creatinine clearance below 35 ml/min) and mild renal osteodystrophy. After 6 months observation of the spontaneous course, the patients were randomly allocated to 6 months oral treatment with either 1,25(OH)2D3 or D3 in initial daily doses of 1 and 100 microgram, respectively, combined with 0.5 g calcium (Calcium Sandoz). 1,25(OH)2D3 had a fast normalizing effect on the biochemical changes of calcium metabolism. D3 had similar, but less pronounced effects. The percent fall in creatinine clearance was greater during than before treatment in all patients on 1,25(OH)2D3 (p less than 0.01) and in 7 of 9 patients on D3 treatment (n.s.). Deterioration of renal function is a major limitation to clinical use of 1,25(OH)2D3 (and D3) in non-dialyzed patients with CRF. In fact, the decreased formation of 1,25(OH)2D3 seen in CRF might protect renal function through the abnormalities in mineral metabolism.