A randomized trial of low-protein diet in type 1 and in type 2 diabetes mellitus patients with incipient and overt nephropathy.
OBJECTIVE
The efficacy of a low-protein diet in the secondary prevention of diabetic nephropathy is not established in patients with type 1 or type 2 diabetes mellitus. To determine whether a low-protein diet slows the decrease in glomerular filtration rate (GFR) and decreases the albumin excretion rate (AER) in diabetic patients with incipient and overt nephropathy, we performed a 2-year prospective, randomized controlled trial comparing the effects of a low-protein diet (0.8 g/kg/day) with a usual-protein diet.


METHODS
The study was conducted in a University hospital and included 63 type 1 and type 2 diabetic patients with either incipient or overt nephropathy and mild renal failure (prestudy GFR, 80 +/- 20 mL/min). The primary outcome measures were decreased in GFR and 24-hour AER.


RESULTS
In the low-protein-diet group, patients were younger (52 +/- 12 versus 63 +/- 9 years old) and more often were type 2 diabetic. During the follow-up period, according to dietary records the low-protein-diet group consumed 16% +/- 3% of total caloric intakes as compared with 19% +/- 4% in the usual-protein-diet group (P < .02), but 24-hour urinary urea excretions did not differ between the two groups. The 2-year GFR decrease was 7 +/- 11 mL/min in the low-protein-diet group and 5 +/- 15 mL/min in the usual-protein-diet group (P = not significant). AER did not increase significantly in the two diet groups during the follow-up period. Blood pressure and glycemic control were similar in the two groups all along the study. The decrease in GFR and AER were also similar in 6 compliant patients according to dietary records and to 24-hour urinary urea excretions from the low-protein-diet group and in 12 patients from the usual-protein-diet group.


CONCLUSIONS
A 2-year low-protein diet did not alter the course of GFR or of AER in diabetic patients with incipient or overt nephropathy receiving renin-angiotensin blockers with strict blood pressure control.
Dussol
Bertrand
B
Centre d'Investigation Clinique, INSERM-APHM, Marseille, France. bdussol@ap-hm.fr
Iovanna
Cecilia
C
Raccah
Denis
D
Darmon
Patrice
P
Morange
Sophie
S
Vague
Philippe
P
Vialettes
Bernard
B
Oliver
Charles
C
Loundoun
Anderson
A
Berland
Yvon
Y
D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000652:urine; D001794:Blood Pressure; D003922:Diabetes Mellitus, Type 1 / Q000178:diet therapy*; D003924:Diabetes Mellitus, Type 2 / Q000178:diet therapy*; D003928:Diabetic Nephropathies / Q000178:diet therapy* / Q000503:physiopathology; D015930:Diet Records; D018753:Diet, Protein-Restricted; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D002149:Energy Intake; D005919:Glomerular Filtration Rate; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008055:Lipids / Q000097:blood; D008875:Middle Aged; D009752:Nutritional Status; D011446:Prospective Studies; D012709:Serum Albumin / Q000032:analysis; D011795:Surveys and Questionnaires
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D006442:Glycated Hemoglobin; D008055:Lipids; D012709:Serum Albumin