What is the DCCT? What are the results?

The Diabetes Control and Complications Trial was a large multi-center
trial involving over 1400 volunteer patients with type 1 diabetes. It
began in 1983, ramped up to full speed by 1989, and ended early in 1993
when the investigators felt the results were clear. The volunteers were
all undergoing "standard" treatment when they were recruited, meaning
one or two injections per day. They were randomly assigned to two
groups. One group continued as before. The other group received
intensive treatment aimed at achieving blood glucose (bG) profiles as
close as possible to normal. The intensive treatment involved multiple
bG checks per day, multiple injections and/or an insulin pump, and
access to and regular consultation with a team of treatment experts.

It is particularly important to note that intensive treatment was
defined as a collaborative effort involving the patient and a skilled
team of health care professionals. It was not defined by particular
techniques, although certain techniques were typically used. The
frequent consultations and availability of a professional team were
critical components of intensive therapy.

The results show that the intensive treatment group did indeed achieve
bG levels closer to normal, and that they experienced far fewer
diabetic complications though also more hypoglycemia. In particular,
patients who maintained HbA1c levels around 7% appear to be much better
off than those whose HbA1c hovers around 9%. (See caveats in the
section on HbA1c.) Though it is not possible to separate the effects of
all the aspects of the intensive treatment, it is reasonable to believe
that lowering average bG may be effective even in isolation from the
other aspects of the intensive treatment. In its position statement,
the ADA says

   Patients should aim for the best level of glucose control they can
   achieve without placing themselves at undue risk for hypoglycemia or
   other hazards associated with tight control.

Though type 2 patients were not included in the study, it is generally
believed that the results showing the benefits of tight control apply
to type 2 patients as well.

The entire position statement was published in most of the ADA's
publications (see "could you recommend some good reading") in the
summer and fall of 1993.

The formal report detailing the results was published in The New England
Journal of Medicine, aka NEJM, of September 30,1993 (v 329 pp 977-986).
The following discussion is based on that article.

Several DCCT subjects participate in m.h.d and are willing to answer
questions related to the personal aspects of DCCT participation.