Descriptions of the participating centers and patient population in the Growth Failure in Children with Renal Diseases Study

The Growth Failure in Children With Renal Diseases Study, a double-blind, multicenter clinical trial with 108 children entered into the control period over 4.3 years of patient enrollment (December 1984 to April 1989), is being extended for 3 years (December 1988 to December 1991) to provide the time needed to accrue additional patients, aged between 1 1/2 and 10 years, with glomerular filtration rates of 20 to 75 ml/min/1.73 m2. The study design of randomization to two treatment arms (1,25-dihydroxyvitamin D vs dihydrotachysterol) requires a total of 108 patients with a minimum of 6 months of treatment to test the long-term effectiveness and safety of 1,25-dihydroxyvitamin D, an essential part of the therapeutic regimen for children with chronic renal insufficiency. The frequent longitudinal assessments of nutrition and growth in children with chronic renal insufficiency can better define the natural history of renal disease and its influence on growth. Similar data in the treatment period will define the impact of treatment with 1,25-dihydroxyvitamin D3 versus dihydrotachysterol on this natural history. Linear growth must be observed long enough (6 to 12 months minimum) to permit valid quantitation and comparison of the two vitamin D treatment arms, the multiple confounding variables that affect growth (e.g., steroid therapy, diabetes mellitus, prior vitamin D treatment) must be rigorously excluded or controlled, and the assignment of patients to the two groups must be random. These controls--sufficient study duration, sufficient patient numbers, and randomization--should eliminate extraneous sources of variation, including seasonal periodicity. This carefully developed, double-blind clinical trial with multiple participating centers and an effective organizational structure is coming close to achieving the goals of the study. An explosion of data regarding the natural history of chronic renal insufficiency and its treatment with vitamin D metabolites will be forthcoming at the conclusion of the study.