The Accord study was a research project where they took two groups of people with diabetes type 2 and put one of the groups into an extremely intensive program to lower blood sugar. This study lasted about four years and was just ordered to stop because this group had 54 more deaths than the other.
They have yet to figure out exactly what caused the deaths. Theories range from the fact that some of the people were way more sick than first thought, to the intensity of the program caused too much stress and anxiety.
They did find out that a combination of lowering blood sugar, cholesterol, and high blood pressure with low doses of aspirin seemed to extend the lives of the other group.