All you need to read in the other general journalsBMJ 2010; 341 doi: https://doi.org/10.1136/bmj.c3561 (Published 07 July 2010) Cite this as: BMJ 2010;341:c3561
Glycaemic control should be tight, but not too tight
In 2008, a landmark trial (ACCORD) was stopped early after it reported unexpected extra deaths associated with intensive hypoglycaemic treatment for type 2 diabetes. Two separate papers from the same trial now report the effect of very tight control on microvascular complications⇑.
The first paper found that aiming for a glycated haemoglobin (HbA1c) target below 6% did not protect patients from advanced renal disease, advanced eye disease, or peripheral neuropathy over three to five years compared with a higher target (7.0-7.9%). Fewer of the intensively treated patients developed more subtle signs of microvascular damage, however, such as albuminuria, worsening visual acuity, or isolated signs of neuropathy.
A second report looked in more detail at risk of retinopathy in close to 3000 of the original 10 251 participants. Over a follow-up of four years, patients aiming for the lower target HbA1c were a third less likely to show progression of retinopathy on fundal photographs than those aiming for the higher target (7.3% v 10.4%; adjusted odds ratio 0.67, 95% CI 0.51 to 0.87). Half of those in the eye study had signs of retinopathy at baseline. Aggressive control of serum lipids—by adding fenofibrate to statins—also reduced the odds of progressive retinopathy in this analysis (0.6, 0.42 to 0.87, relative to adding placebo). Aggressive control of blood pressure, the third element of the ACCORD trial, did not. None of the interventions prevented moderate visual loss.
What are doctors to make of these results? Two editorials (doi:10.1016/S0140-6736(10)61028-8; doi:10.1056/NEJMe1005667) remain upbeat about the importance of good glycaemic control in people with type 2 diabetes and a high risk of cardiovascular disease, the inclusion criteria for ACCORD. Aiming for an HbA1c of lower than 6% was probably too …