Inflammation and reduced hemoglobin levels are differentially associated with coronary artery disease in non-albuminuric subjects with and without type 2 diabetes mellitus

Abstract

Abstract Aims This study aimed to evaluate the clinical significance of inflammation and hemoglobin in relation to the risk of coronary artery disease in subjects with type 2 diabetes mellitus (T2DM) and preserved kidney function. Methods In this cross-sectional study, we recruited 638 participants − 254 with T2DM- with no known cardiovascular disease, normal glomerular filtration rates and without albuminuria that were subjected to coronary angiography. Hemoglobin and serum levels of inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor (TNF) α and interleukin (IL) 6, were measured. Results Patients with diabetes and significant CAD presented increased levels of hs-CRP (46% increase, P = 0.02). However, neither the hs-CRP levels nor the cytokines were related to the severity of the stenosis in the group of subjects with diabetes in a multivariable analysis. Conversely, both inflammatory cytokines and albuminuria were directly related to the percentage of stenosis in subjects without T2DM (R2 = 0.038, P < 0.001). Patients with diabetes presented lower hemoglobin levels, particularly in those who also had significant CAD (14.4 [13.6–15.1] vs. 13.6 [12.2–14.8] g/dL, P = 0.03). Thus, subjects with diabetes and anemia presented increased coronary stenosis when compared with those without anemia (45% increase, P < 0.01). Similarly, hemoglobin levels and albuminuria were inversely related with the severity of stenosis exclusively in subjects with diabetes, even after adjusting for multiple confounding factors (R2 = 0.081, P < 0.001). Conclusions The results suggest that reductions in hemoglobin levels in subjects with T2DM and normoalbuminuria may constitute a more relevant risk factor for CAD than inflammation.