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This review article provides an overview of the study design, methods and results used in The Diabetes Control and Complications Trial (DCCT) with emphasis on the renal outcomes and the role of medical nutrition therapy.

• Type 1 diabetes
• Criteria not specified (refer to description of actual data sample)

 

Criteria not specified (refer to description of actual data sample)

Recruitment:  Not discussed. 

Design:

This article was a review article of a large randomized clinical trial.  The original study had a primary prevention cohort (subjects had no retinopathy and albuminuria <40 mg/ 24 hours) and a secondary prevention cohort (subjects had mild to moderate retinopathy and albuminuria <200 mg/24 hours).  All subjects were randomly assigned to either conventional therapy or intensive therapy.

Blinding Used (if applicable):  Not discussed

Intervention (if applicable):  Review article of an RCT 

Statistical Analysis:  Not discussed 

Timing of measures:

• Not discussed

Dependent variables:

• Microalbuminuria
• Albuminuria
• Blood glucose
• HbA_1c

Independent variables:

• Conventional Therapy
  • 1 or 2 injections of insulin/d
  • Monitored urine or blood glucose
  • Clinic appointments q 3 months
  • Treatment goals: clinical well-being, absence of symptoms of hypoglycemia or hyperglycemia, HbA_1c <13.11%
  • Nutrition intervention: counseling with RD q 6 mos on diet of 10-25% protein, 30-35% fat, 34-55% carbohydrate; Step I cholesterol-lowering diet.
• Intensive Therapy
  • >=3 daily injections of insulin or use of an insulin pump
  • Self-monitoring of blood glucose at least 4 x/d and at 3 a.m. 1 x/wk
  • Monthly clinic appointments
  • Treatment goals:  blood glucose 70-120 mg/dl preprandially, postprandial <180 mg/dl and 3 a.m. >65 mg/dl ;HbA_1c: <6.05%
  • Nutrition intervention: received counseling from RD as needed—usually monthly for the first 6 mos to reach goals and to teach self-management skills of using food and glucose records to adjust insulin for expected changes in food intake and physical activity.

Control Variables:

• Not discussed

Initial N: Not discussed

Attrition (Final N):  1441 (726 in primary prevention trial; 715 in secondary prevention trial)

Age: 13-39 years

Ethnicity:  Not discussed

Other Relevant Demographics:

• Primary prevention trial: 1-5 years duration of diabetes
• Secondary prevention trial: 1-15 years duration of diabetes

Anthropometrics:  Not discussed

Location: 29 centers

Primary Prevention Group:

Decreased albumin excretion by 15% after 1-yr of therapy in the intensive therapy group and no further significant change during follow-up

Secondary Prevention Group:

6.5% increase/yr in albumin excretion rate with conventional therapy versus almost no change in the intensive group.

Subjects in the intensive treatment group had 39% decrease in microalbuminuria and a 54% decrease in albuminuria.

Women benefited less from intensive therapy with an 18% decreased risk for albuminuria compare to men with a 57% decrease in risk.

For each 10% higher mean HbA_1c, the risk for developing microalbuminuria was 31% greater for the conventional therapy group and 29% greater in the intensively treated group. The risk for developing albuminuria for each 10% higher mean HbA_1c was 71% greater in the conventionally treated group and 57% greater in the intensively treated group.

Regardless of the treatment group, for every 10% decreased in HbA_1c, there was a 25% risk decrease for microalbuminuria, a 39% decreased risk for sustained microalbuminuria, a 36% risk decrease for advanced microalbuminuria and a 44% risk decrease in the secondary cohort for albuminuria.

Research on the DCCT patients who received intensive diabetes therapy showed that adherence to certain diet behaviors was associated with a 1 unit lower mean HbA_1c level. Adherence to the prescribed meal plan, adjusting food and/or insulin in response to hyperglycemia, adjusting insulin dose for changes in food intake, and consistency in consumption of a bedtime snack were associated with lower HbA_1c levels. Whereas, over treatment of hypoglycemia and consumption of extra nighttime snacks beyond the meal plan were associated increased HbA_1c levels.

University/Hospital:

Massachusetts General Hospital

Intensive diabetes therapy demonstrated a preservation of renal function, which would be a cost savings with prevention of renal failure.

In the intensive treatment group, the number of RD visits in the 1^st year was ~7 and for the conventional treatment group, the number of RD visits in the 1^st year was 2.