C-Reactive Protein and Glycemic Control in Adults With Diabetes

OBJECTIVE: Recent evidence suggests that poor glycemic control is significantly associated with the development of macrovascular complications of diabetes. Studies have indicated that C-reactive protein (CRP) is an important risk factor for cardiovascular disease. The purpose of this study was to determine the relation between CRP and HbA(1c) in a large national sample of individuals with diabetes. RESEARCH DESIGN AND METHODS: A nationally representative sample of noninstitutionalized U.S. adults aged 17 years and over with nongestational diabetes was derived from the National Health and Nutrition Examination Survey III (1988-1994) (n = 1,018). Respondents with diabetes were stratified by HbA(1c) level. The main outcome measure was elevated (>0.30 mg/dl) CRP. RESULTS: In unadjusted analyses, respondents with diabetes who had elevated HbA(1c) levels (> or =9.0%) had a significantly higher percent of elevated CRP than people with low (9.0% (OR 2.15, 95% CI 1.07-4.32) and for HbA(1c) >11.0% (4.40, 1.87-10.38). Higher HbA(1c) also predicted elevated CRP in the regression model when HbA(1c) was analyzed as a continuous variable (1.20, 1.07-1.34). CONCLUSIONS: In this study, the likelihood of elevated CRP concentrations increased with increasing HbA(1c) levels. These findings suggest an association between glycemic control and systemic inflammation in people with established diabetes.