The Relationship between Plasma Osteopontin Level and Proteinuria in Diabetic Patients

Elevated serum levels of osteopontin (OPN) have been associated with cardiovascular disease, diabetic nephropathy, and autoimmune disease activity. The aim of this study was to investigate the relationship between OPN serum levels and renal damage in type 2 diabetes patients. This analytical cross-sectional study was carried out in Yazd, Iran from April to September 2017. Micro-albuminuria and creatinine (Cr) in 750 patients were measured and 180 included patients were divided into the three groups of 60 subjects based on the level of micro-albuminuria; normal (group A), micro proteinuria (group B) and macro proteinuria (group C). Body weight, height, blood pressure, body mass index (BMI), HbA1c and OPN were assessed. Among 179 patients, 60 of them were normal for proteinuria, 59 patients had micro-proteinuria and 60 ones had macro- proteinuria. The mean age of participants was 58.96 ( ± 11.10) years (range 26-80 years), 90 patients (50.8%) were males and 88 ones (49.2%) were females. The mean OPN levels were significantly higher in group C compared to group B, and in group B compared to group A (P = 0.0001). Serum OPN was correlated positively with HbA1c (P: 0.012), Cr (P = 0.010) and glomerular filtration rate (GFR) (P = 0.002). There was a significant difference in the mean of OPN level among the subgroups with the history of ischemic heart disease (IHD) and HbA1C (P=0.035, and 0.047 respectively). These findings suggest that OPN is involved in chronic disease activity, and there is an independent association between plasma levels of OPN, and nephropathy in diabetic patients.