Effect of dietary protein restriction on prognosis in patients with diabetic nephropathy.
BACKGROUND
Recent data suggest that dietary protein restriction improves survival and delays the progression to end-stage renal disease (ESRD) in non-diabetic nephropathies. The purpose of our study was to determine the effect of dietary protein restriction on survival and progression to ESRD in diabetic nephropathy.


METHODS
A four-year prospective, controlled trial with concealed randomization was performed comparing the effects of a low-protein diet (0.6 g/kg/day) with a usual-protein diet. The study included 82 type 1 diabetic patients with progressive diabetic nephropathy [pre-study mean decline in glomerular filtration rate (GFR) 7.1 mL/min/year (95% CI, 5.8 to 8.5)]. The main outcome measures were decline in GFR and development of ESRD or death.


RESULTS
During the follow-up period the usual-protein diet group consumed 1.02 g/kg/day (95% CI; 0.95 to 1.10) as compared with 0.89 (0.83 to 0.95) in the low-protein diet group (P = 0.005). The mean declines in GFR were 3.9 mL/min/year (2.7 to 5.2) in the usual-protein diet group and 3.8 (2.8 to 4.8) in the low-protein diet group. ESRD or death occurred in 27% of patients on a usual-protein diet as compared with 10% on a low-protein diet (log-rank test; P = 0.042). The relative risk of ESRD or death was 0.23 (0.07 to 0.72) for patients assigned to a low-protein diet, after an adjustment at baseline for the presence of cardiovascular disease (P = 0.01). Blood pressure and glycemic control were comparable in the two diet groups during the follow-up period.


CONCLUSIONS
Moderate dietary protein restriction improves prognosis in type 1 diabetic patients with progressive diabetic nephropathy in addition to the beneficial effect of antihypertensive treatment.
Hansen
Henrik Post
HP
Steno Diabetes Center, Niels Steensens Vej 2, 2820 Gentofte, Denmark. posthansen@dadlnet.dk
Tauber-Lassen
Ellis
E
Jensen
Berit R
BR
Parving
Hans-Henrik
HH
D000328:Adult; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D003928:Diabetic Nephropathies / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D018753:Diet, Protein-Restricted; D005260:Female; D005919:Glomerular Filtration Rate; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007676:Kidney Failure, Chronic / Q000209:etiology; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D011379:Prognosis; D011446:Prospective Studies; D012044:Regression Analysis; D006435:Renal Dialysis
D006442:Glycated Hemoglobin