Association between osteoprotegerin, fetuin-A, carotid intima media thickness, and urinary albumin excretion in Type 2 diabetes.

Aims: Vascular calcification and atherosclerosis play a vital role in the development of cardiovascular morbidity and mortality in diabetic patients, especially when complications of diabetic nephropathy occur. Osteoprotegerin (OPG) and fetuin-A are two markers of vascular calcification. We evaluated the association between these vascular markers and urinary albumin excretion in diabetic patients.

Method: Three groups were arranged containing 40 patients: normoalbuminuric (Group 1), microalbuminuric (Group 2), and macroalbuminuric (Group 3). In addition to the obtained data, levels of hs-CRP (high sensitivity-CRP) and homocysteine were examined.

Results: OPG levels of patients in Group 2 were higher than in Group 1 (p = 0.058). OPG levels in Group 3 were lower than in Groups 1 or 2 (p = 0.014 and 0.000, respectively). Levels of fetuin-A in Group 2 were determined to be lower than in Groups 1 and 3 (p = 0.001 and 0.000, respectively). Carotid intima media thickness (CIMT) in Group 3 was higher than in Group 1 (p = 0.002). CIMT in Group 2 was also higher than in Group 1 (p = 0.039). A positive correlation between fetuin-A and OPG was found (p = 0.012, r = 0.393). Additionally, a positive correlation between hs-CRP and fetuin-A in Group 2 (p = 0.020, r = 0.367) and a negative correlation between hs-CRP and OPG in Group 3 (p = 0.036, r = -0.333) were observed.

Conclusions: The differences found between albuminuria and OPG or fetuin-A may be due to the different doses and variety of medications the patients received, in addition to genetic and racial factors. So far, in our country, polymorphisms related to OPG and fetuin-A have not been defined. Further detailed studies about polymorphisms will have additional value.