Prevention of cardiovascular disease through glycemic control in type 2 diabetes: a meta-analysis of randomized clinical trials.
OBJECTIVE
Randomized clinical trials (RCTs) aimed at the assessment of the efficacy of lowering blood glucose in the prevention of diabetic complications have always failed to detect a significant effect on cardiovascular events. Aim of this meta-analysis is the assessment of the effects of improvement of glycemic control on the incidence of cardiovascular diseases in patients with type 2 diabetes.


METHODS
The RCTs were included in this meta-analysis if: a) the between-group difference in mean HbA1c during the trial was at least 0.5%, b) they had a planned duration of treatment of at least 3 years, c) if they had a cardiovascular endpoint. Data for analysis were extracted independently by two observers and potential contrasts were resolved by a senior investigator.


RESULTS
Five studies (17,267 and 15,362 patients in the intensive and conventional therapy groups, respectively) were included. Intensive treatment, which reduced mean HbA1c by 0.9% on average, was associated with a significant reduction of incident cardiovascular events and myocardial infarction (OR 0.89 [0.83-0.95] and 0.86 [0.78-0.93], respectively), but not of stroke or cardiovascular mortality (OR 0.93 [0.81-1.07] and 0.98 [0.77-1.23], respectively). In meta-regression analysis, a higher BMI duration of diabetes, and incidence of severe hypoglycaemia were associated with greater risk for cardiovascular death in intensive treatment groups.


CONCLUSIONS
Intensified hypoglycaemic treatment in type 2 diabetic patients leads to a significant reduction of the incidence of myocardial infarction, while it does not affect the incidence of stroke and cardiovascular mortality. Hypoglycemia induced by intensified treatment could be associated with increased cardiovascular mortality.
Section of Geriatric Cardiology, Department of Cardiovascular Medicine, Azienda Ospedaliero-Universitaria Careggi, Via delle Oblate 4, 50141 Florence, Italy. edoardo.mannucci@unifi.it
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Mannucci
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Monami
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Lamanna
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Gori
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Marchionni
D002318:Cardiovascular Diseases / Q000401:mortality / Q000517:prevention & control*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000401:mortality; D003925:Diabetic Angiopathies / Q000401:mortality / Q000517:prevention & control*; D006801:Humans; D006943:Hyperglycemia / Q000188:drug therapy* / Q000401:mortality; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic
D007004:Hypoglycemic Agents