Design and statistical issues of the Modification of Diet in Renal Disease Trial. The Modification of Diet in Renal Disease Study Group

Control Clin Trials. 1991 Oct;12(5):566-86. doi: 10.1016/0197-2456(91)90069-x.


The Modification of Diet in Renal Disease Trial is a multicenter randomized clinical trial for men and women aged 18-70 years with chronic renal disease who are not on dialysis and who have not had a kidney transplant. Study participants are randomized in a 2 x 2 factorial design to diets containing different amounts of protein and phosphorus and to two levels of blood pressure control. The prescribed modifications differ depending on the level of a patient's kidney function. The primary outcome variable to compare diet or blood pressure groups is each patient's slope (or the change) in glomerular filtration rate with time. This paper describes the study design with particular emphasis on sample size determination. Special statistical analysis issues that arise with slope as the outcome are also discussed.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Blood Pressure
  • Dietary Proteins / administration & dosage
  • Female
  • Glomerular Filtration Rate
  • Humans
  • Kidney Diseases / diet therapy*
  • Kidney Diseases / physiopathology
  • Kidney Diseases / urine
  • Male
  • Middle Aged
  • Phosphorus / administration & dosage
  • Proteinuria


  • Dietary Proteins
  • Phosphorus