Effect of Dietary Protein Restriction on Prognosis in Patients With Diabetic Nephropathy (LPD)

The purpose of the investigators study was to determine the effect of dietary protein restriction on survival and progression to end stage renal disease (ESRD) in diabetic nephropathy.

Study Overview

• Status: Completed
• Conditions: Type 1 Diabetes Mellitus With Diabetic Nephropathy
• Intervention / Treatment: Dietary supplement: low protein diet; Dietary supplement: normal protein diet

Detailed Description

The study was a prospective, randomized, unmasked, controlled trial carried out at the Steno Diabetes Center. With concealed randomization the patients were (in blocks of two according to the level of GFR) assigned to receive either a usual-protein diet or a low-protein diet.

After randomization an iso-caloric low-protein diet of 0.6 g/kg/day was prescribed to patients in the low-protein diet group. The usual-pro tein diet consisted of the patients' pre-study diet.

The planned duration of follow-up was four years, scheduled visits every three-months. All patients gave complete history of medication, underwent examination of weight, urinary albumin-, sodium- and urea excretion, serum albumin, serum urea, hemoglobin, hemoglobin A1c, blood pressure, serum total-cholesterol, high-density lipoprotein (HDL) cholesterol.

GFR, serum triglycerides,calcium and phosphorous, anthropometric measurements, nutritional status and smoking habits were evaluated every six months.

Dietary protein intake was estimated on the basis of three consecutive 24-hour urine samples completed before each visit, using urinary excretion of urea nitrogen.

GFR was measured by plasma clearance of 51Cr-EDTA over a 4 hour period and standardized for 1.73m2 body surface area using the same surface for each patient during the study.

• Study Type: Interventional
• Enrollment (Actual): 82
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Denmark
  • Gentofte, Denmark, 2820
    • Steno Diabetes center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Diabetes mellitus type 1
• duration at least 10 years
• onset before age of 35,
• presence of diabetic retinopathy
• albuminuria>=300mg/24 h in at least 2/3 sterile urine samples
• no clinical or laboratory evidence of other kidney or urinary tract disease
• GFR above 20mL/min/1.73M2
• pre-study decline in GFR>= 2 mL/min/year

Exclusion Criteria:

• pregnancy
• history of congestive heart failure or myocardial infarction or coronary bypass surgery within the last three months

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Low protein diet	Dietary supplement: low protein diet; An iso-caloric low protein diet of 0.6 g/kg/day was prescribed during the whole study duration. The same dietician gave nutritional advices at least every three months during the whole study period. Patients were also seen by the same doctor during each visit for the whole study period. Supplementation of Calcium of 500mg/day. Urine albumin losses >= 2 g/day wre replaced by increasing dietary protein on a gram-for-gram basis, only if the patient was compliant with the prescribed low-protein diet.
Active Comparator: Normal protein diet	Dietary supplement: normal protein diet; The patients pre-study diet during the whole study period Patients were also seen by the same doctor during each visit for the whole study period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cumulative incidence of ESRD requiring dialysis or transplantation, and death	Cause of death was obtained from death certificate by an independent observer. Before the development of uremic symptoms, patients were referred to the department of nephrology at the University Hospital of Herlev or Rigshospitalet, when GFR deteriorated below 10 to 20 ML/min/1.73m2, where accepted criteria for initiation of dialysis and transplantation were applied on patients from both diet groups. Patients continued their scheduled visits and treatment in the study until the end of the four-year follow up. This was assesed every 3 months until the end of the 4 year follow up period.	4 years
Rate of decline of GFR	rate of decline was measured if the patient had a minimum of one year of follow up and a minimum of 3 GFR measures during the study. All measures of GFR during the study period (including baseline) were used to calculate the rate of decline(the slopes) of GFR. GFR was measured every 6 months during the 4 years of follow up.	4 years

Collaborators and Investigators

• Sponsor: Steno Diabetes Center Copenhagen
• Investigators: Principal Investigator: Henrik P Hansen, MD, Steno Diabetes Center Copenhagen

Study record dates

Study Major Dates

• Study Start: April 1, 1995
• Primary Completion (Actual): June 1, 2000
• Study Completion (Actual): June 1, 2000

Study Registration Dates

• First Submitted: January 13, 2012
• First Submitted That Met QC Criteria: January 30, 2012
• First Posted (Estimate): January 31, 2012

Study Record Updates

• Last Update Posted (Estimate): January 31, 2012
• Last Update Submitted That Met QC Criteria: January 30, 2012
• Last Verified: January 1, 2012

More Information

Terms related to this study

• Keywords: survival; ESRD; type 1 diabetes; diabetic nephropathy; GFR; protein restriction; progressive renal disease
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Immune System Diseases; Autoimmune Diseases; Urologic Diseases; Endocrine System Diseases; Diabetes Complications; Diabetes Mellitus; Kidney Diseases; Diabetes Mellitus, Type 1; Diabetic Nephropathies
• Other Study ID Numbers: Low Protein Diet