Effects of glycaemic control on cardiovascular disease in diabetic American Indians: the Strong Heart Study.
OBJECTIVE
Diabetes increases the risk of cardiovascular disease (CVD). Only part of this excess risk is explained by diabetes-associated hypertension, obesity, and lipid disorders. Poor glycaemic control may help explain the residual CVD risk. The aim of this study was to determine whether variations in glycaemic control are associated with CVD risk in diabetic individuals.


METHODS
We examined longitudinal data from the Strong Heart Study, a population-based study of CVD and its risk factors among American Indians (a population with a high prevalence of diabetes). Diabetes was defined using the 1998 World Health Organization criteria: fasting plasma glucose >/= 126 mg/dl or 2-h plasma glucose >/= 200 mg/dl. American Diabetes Association guidelines for glycaemic control were used: good, A(1c) < 7%; fair, 7-7.9%; and poor, >/= 8%. The analysis was based on data from diabetic individuals with no CVD at baseline.


RESULTS
During 9 years of follow-up, 494 of the 2011 diabetic participants developed CVD. Although Cox multivariate regression modelling showed dose-response effects of glycaemic control on overall CVD and coronary heart disease (CHD) incidence, the relationships were weakened when adjusted for confounding variables. Kaplan-Meier analysis, however, showed that diabetic individuals with poor baseline glycaemic control had significantly increased proportions of overall CVD and CHD (P = 0.001) during the 9 years of follow-up, compared with those who had good or fair control.


CONCLUSIONS
These findings highlight the importance of risk factors, such as high blood pressure and dyslipidaemia, in increasing CVD risk in those with diabetes.
Lu
W Q
WQ
MedStar Research Institute, Hyattsville, MD, and Washington Hospital Center, Washington, DC, USA.
Resnick
H E
HE
Jablonski
K A
KA
Jain
A K
AK
Jones
K L
KL
Robbins
D C
DC
Howard
B V
BV
D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D001794:Blood Pressure; D002784:Cholesterol / Q000097:blood; D003327:Coronary Disease / Q000097:blood / Q000453:epidemiology / Q000209:etiology; D003925:Diabetic Angiopathies / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007198:Indians, North American; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors; D014280:Triglycerides / Q000097:blood; D014481:United States / Q000453:epidemiology
D001786:Blood Glucose; D014280:Triglycerides; D002784:Cholesterol