DCCT: study design

1
DCCT study design
Patients with type 1 diabetes (n 1441)
Secondary intervention (n 715)
Primary prevention (n 726)
Randomise
Randomise
Conventional
Intensive
Conventional
Intensive
DCCT N Engl J Med 199332997786
2
DCCT treatment conditions

• Intensive group (n 711)
• Aim symptom-free plasma glucose 3.9-6.7 mmol/L
  before meals, lt 10 mmol/L after meals, gt 4.0
  mmol/l at 03.00 a.m. and HbA1c lt 6.5
• ? 3 insulin injections / day or insulin pump
• ? 4 daily blood glucose tests
• Hospitalisation for initiation
• Comprehensive education programme
• Frequent dietary instructions
• Monthly clinic visits

• Conventional group (n 730)
• Aim to avoid symptoms of hyper / hypoglycaemia
• 1 or 2 insulin injections per day
• Daily self-monitoring
• Initial diet and exercise education
• Quarterly visits

DCCT N Engl J Med 199332997786
3
DCCT intensive therapy significantly reduces and
maintains HbA1c
Adapted from N Engl J Med 199332997786, EDIC
JAMA 200228725639
4
DCCT intensive therapy reduces microvascular
complications
Microalbuminuria 34 reduction
Retinopathy 76 reduction
Patients ()
Patients ()
Years
urinary albumin excretion 40 mg per 24 hours
Adapted from N Engl J Med 199332997786
5
DCCT microvascular complications increase as
HbA1c increases
HbA1c ()
DCCT N Engl J Med 199332997786
6
Retinopathy 7 years after the DCCT
Cumulative incidence of retinopathy progression
Adapted from JAMA 200228725639
7
DCCT the price of improved diabetic control
hypoglycaemia
Rate pf progression of retinopathy (per 100
patient years)
Rate of severe hypoglycaemia (per 100 patient
years)
Adapted from N Engl J Med 199332997786
8
Economic analysis - DCCT

• From a health care system perspective, intensive
  therapy represents a good monetary value for the
  investment1
• Although intensive therapy is expensive, when
  the costs of complications are factored in, it
  becomes cost-effective for the treatment of type
  1 diabetes2

1. DCCT Research Group. JAMA 19962761409-15 2.
Herman WH, Eastman RC. Diabetes Care
199821(suppl 3)C19-24