Systematic review: glucose control and cardiovascular disease in type 2 diabetes.
BACKGROUND
Results from clinical trials examining the effect of intensive glucose control on cardiovascular disease have been conflicting.


OBJECTIVE
To summarize clinical benefits and harms of intensive versus conventional glucose control for adults with type 2 diabetes.


METHODS
Studies were retrieved by systematically searching the MEDLINE database (January 1950 to April 2009) with no language restrictions.


METHODS
Two independent reviewers screened abstracts or full-text articles to identify randomized trials that compared clinical outcomes in patients with type 2 diabetes receiving intensive glucose control and those receiving conventional glucose control.


METHODS
Two investigators independently abstracted data on study variables and outcomes, including severe hypoglycemia, cardiovascular disease, and all-cause mortality.


RESULTS
5 trials involving 27,802 adults were included. Intensive glucose targets were lower in the 3 most recent trials. Summary analyses showed that compared with conventional control, intensive glucose control reduced the risk for cardiovascular disease (relative risk [RR], 0.90 [95% CI, 0.83 to 0.98]; risk difference per 1000 patients per 5 years [RD], -15 [CI, -24 to -5]) but not cardiovascular death (RR, 0.97 [CI, 0.76 to 1.24]; RD, -3 [CI, -14 to 7]) or all-cause mortality (RR, 0.98 [CI, 0.84 to 1.15]; RD, -4 [CI, -17 to 10]). Intensive glucose control increased the risk for severe hypoglycemia (RR, 2.03 [CI, 1.46 to 2.81]; RD, 39 [CI, 7 to 71]). As was seen in the overall analyses, pooled findings from the early and more recent trials showed that intensive glucose control reduced the risk for cardiovascular disease and increased the risk for severe hypoglycemia.


CONCLUSIONS
Summary rather than individual data were pooled across trials.


CONCLUSIONS
Intensive glucose control reduced the risk for some cardiovascular disease outcomes (such as nonfatal myocardial infarction), did not reduce the risk for cardiovascular death or all-cause mortality, and increased the risk for severe hypoglycemia.
Kelly
Tanika N
TN
Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, 1440 Canal Street, Suite 2000, New Orleans, LA 70112, USA. tkelly@tulane.edu
Bazzano
Lydia A
LA
Fonseca
Vivian A
VA
Thethi
Tina K
TK
Reynolds
Kristi
K
He
Jiang
J
D001786:Blood Glucose / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000401:mortality / Q000517:prevention & control*; D002423:Cause of Death; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D006801:Humans; D007003:Hypoglycemia / Q000139:chemically induced; D007004:Hypoglycemic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D012307:Risk Factors
D001786:Blood Glucose; D007004:Hypoglycemic Agents