Effect of a Very Low-Protein Diet on Outcomes: Long-term Follow-up of the Modification of Diet in Renal Disease (MDRD) Study
Received 28 February 2008; accepted 7 August 2008. published online 28 October 2008.
Refers to article:
Dietary Protein Restriction in CKD: The Debate Continues
T. Alp Ikizler
American Journal of Kidney Diseases
February 2009 (Vol. 53, Issue 2, Pages 189-191) Full Text |
Full-Text PDF (62 KB)
Background
The long-term effect of a very low-protein diet on the progression of kidney disease is unknown. We examined the effect of a very low-protein diet on the development of kidney failure and death during long-term follow-up of the Modification of Diet in Renal Disease (MDRD) Study.
Study Design
Long-term follow-up of study B of the MDRD Study (1989-1993).
Setting & Participants
The MDRD Study examined the effects of dietary protein restriction and blood pressure control on progression of kidney disease. This analysis includes 255 trial participants with predominantly stage 4 nondiabetic chronic kidney disease.
Intervention
A low-protein diet (0.58 g/kg/d) versus a very low-protein diet (0.28 g/kg/d) supplemented with a mixture of essential keto acids and amino acids (0.28 g/kg/d).
Outcomes
Kidney failure (initiation of dialysis therapy or transplantation) and all-cause mortality until December 31, 2000.
Results
Kidney failure developed in 227 (89%) participants, 79 (30.9%) died, and 244 (95.7%) reached the composite outcome of either kidney failure or death. Median duration of follow-up until kidney failure, death, or administrative censoring was 3.2 years, and median time to death was 10.6 years. In the low-protein group, 117 (90.7%) participants developed kidney failure, 30 (23.3%) died, and 124 (96.1%) reached the composite outcome. In the very low-protein group, 110 (87.3%) participants developed kidney failure, 49 (38.9%) died, and 120 (95.2%) reached the composite outcome. After adjustment for a priori–specified covariates, hazard ratios were 0.83 (95% confidence interval, 0.62 to 1.12) for kidney failure, 1.92 (95% confidence interval, 1.15 to 3.20) for death, and 0.89 (95% confidence interval, 0.67 to 1.18) for the composite outcome in the very low-protein diet group compared with the low-protein diet group.
Limitations
Lack of dietary protein measurements during follow-up.
Conclusion
In long-term follow-up of the MDRD Study, assignment to a very low-protein diet did not delay progression to kidney failure, but appeared to increase the risk of death.
1Department of Medicine, Division of Nephrology, Tufts Medical Center, Boston, MA
2Division of Nephrology, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, David Geffen School of Medicine at UCLA, UCLA School of Public Health, Los Angeles, CA
3Department of Biostatistics and Epidemiology, Cleveland Clinic Foundation, Cleveland, OH
4Division of Nephrology, Hennepin County Medical Center, Minneapolis, MN
6Division of Clinical Epidemiology, University of Utah, Salt Lake City, UT
Address correspondence to Mark J. Sarnak, MD, MS, 800 Washington St, #391, Boston, MA 02111
Because an author of this manuscript is an editor for AJKD, the peer-review and decision-making processes were handled entirely by an Associate Editor (Paul Muntner, PhD, MHS, Mount Sinai School of Medicine) who served as Acting Editor-in-Chief. Details of the journal's procedures for potential editor conflicts are given in the Editorial Policies section of the AJKD website.
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