Reappraisal of the efficacy of intensive glycaemic control on microvascular complications in patients with type 2 diabetes: a meta-analysis of randomised control-trials

Objective.- To re-assess the effect of tight glycaemic control on diabetic microvascular complications. Method.- Meta-analysis and trial sequential analyses of randomised trials included in Hemmingsen et al that specifically assessed glycaemic control with a specific HbA1clevel targeted in the intervention group, and compared intensive glycaemic control versus standard glycaemic control. Results.- Seven clinical trials that randomised 28 614 participants with type 2 diabetes (15 269 to intensive control and 13 345 to conventional control), including 3 sub-studies, were included. Strict control of blood glucose levels is associated with a reduction of retinopathy progression (RR=0.77, 95% CI 0.66–0.89, I2=33%), incidence or progression of macular oedema (RR=0.66, 95% CI 0.40–0.99, I2=0%), number of photocoagulations (RR=0.84, 95% CI 0.73–0.97, I2=0%), risk of microalbuminuria (RR=0.76, 95% CI 0.64–0.9, I2=76%) and risk of “macroalbuminuria or proteinuria” (RR=0.68, 95% CI 0.55–0.85, I2=36%). Conclusion.- This meta-analysis has shown that a tight control of blood glucose levels is associated with a decrease of specific microvascular complication of diabetes: photocoagulation, progression of diabetic retinopathy, incidence or progression of macular oedema, risk of microalbuminuria and risk of macroalbuminuria or proteinuria. Regarding all the other outcomes (vision loss, surgery of cataract, proliferative or non-proliferative retinopathy, death related to kidney disease, development of kidney disease, doubling of serum creatinine, neuropathy), no significant result was found.