To lower or not to lower? Making sense of the latest research on intensive glycaemic control and cardiovascular outcomes
- 1School of Nursing, McMaster University, Hamilton, Ontario, Canada
- 2McMaster University Medical Centre, Hamilton, Ontario, Canada
Diabetes is an extremely burdensome and costly chronic disease. It affects an estimated 4–6% of the world’s population, and its prevalence continues to rise.1 2 Diabetes is a major cause of blindness, end stage renal disease, and cardiovascular complications, all of which are preventable.3 4 Clinical practice guidelines for the management of diabetes emphasise the importance of optimal glycaemic control. Specifically, some clinical practice guidelines have suggested targeting a glycated haemoglobin (Hb) A1c concentration ⩽7%, or ⩽6% for those able to safely achieve it.5
ACCORD, ADVANCE, AND UKPDS 10-YEAR FOLLOW-UP
With the recent publication of 3 notable trials, a great deal of debate and confusion has been created about the cardiovascular effects of lowering glucose to near-normal concentrations in people with type 2 diabetes. The Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial, the Action in Diabetes and Vascular Disease: Preterax and Damicron Modified Release Controlled Evaluation (ADVANCE) trial, and the 10-year follow-up of the UK Prospective Diabetes Study (UKPDS) provide complementary information about cardiovascular risk reduction with glucose lowering that can be used to help patients to develop evidence-based goals of therapy individualised to their own circumstances. See abstracts in this issue on pages 12–14.
ACCORD, ADVANCE, and the 10-year follow-up of the UKPDS all reported the effects of intensive glucose lowering on vascular outcomes.6–8 All 3 studies were randomised controlled trials, with an intensive glucose-lowering group and a “standard” control group with less stringent glycaemic targets. The trials differed in many respects (table 1) that may help to reconcile the differences in results (table 2).
Participants and duration of follow-up
There were important differences in the types of participants recruited and the duration of follow-up. ACCORD enrolled >10 000 patients starting in 2001 and followed them for a median of 3.4 years, at which point the intervention was discontinued (17 …