In a follow-up study of the 10-year DCCT (Diabetes Control and Complications Trial), it was found that people who intensively managed their blood sugar significantly reduced their risk of developing retinopathy and kidney disease.
The findings were reported in the February 10 issue of The New England Journal of Medicine. During the DCCT, the progress of people on intensive therapy was compared to that of people on conventional therapy. Intensive therapy consisted of keeping BG levels as close to normal as possible (HbA1c 6%) through at least three insulin injections per day or an insulin pump, and frequent self-monitoring of BGs. Conventional treatment consisted of one or two insulin injections per day with a urine or blood glucose test.
By the end of the DCCT (after an average of 6.5 years), HbA1c levels in the intensive-treatment group averaged 7.2% versus 9.1% in the conventional-treatment group. Compared to the conventional-treatment group, the intensive-treatment group had a much lower rate of diabetic eye, nerve and kidney disease.
When the trials concluded in 1993, people who had been receiving conventional treatment were taught intensive therapy, and all participants were encouraged to remain on it.
During the first four years of the follow-up study (known as EDIC, or Epidemiology of Diabetes Interventions and Complications), HbA1c levels of people who had been in both groups leveled off at about 8%, which meant that glucose levels of people who had been in intensive therapy rose, and BG levels of people who had been conventionally treated had improved. Despite this finding, the intensive-therapy group continued to show lower risks of eye and kidney disease than those who had been conventionally treated during the DCCT.
Although the DCCT studied people with type 1, the results of the follow-up study are significant for both type 1 and 2, showing earlier and longer intensive therapy helps to cut the risks of developing complications.