Acute-phase proteins and microalbuminuria among patients with type 2 diabetes

Abstract 

Objective: to determine the relationship between acute-phase proteins and microalbuminuria in type 2 diabetic patients without clinical evidence of macrovascular disease. Research design and methods: We studied cross-sectionally 64 non-smoking outpatients with type 2 diabetes mellitus without clinical evidence of cardiovascular disease attended at Brazilian University General Hospital aged 59.5±8.1 years and with a known duration of diabetes of 11.5±8 years. Urinary albumin excretion rate (AER) was determined in timed overnight urine samples. Serum α₁-acid glycoprotein (AGP) and plasma fibrinogen were determined by immunoturbidimetry assay and serum C-reactive protein (CRP) was measured by a high-sensitive immunonephelometry assay. Results: A higher levels of AGP (P=0.0000), CRP (P=0.003) and fibrinogen (P=0.0001) were found in microalbuminuric (n=26) than in normoalbuminuric patients (n=38). All the acute-phase proteins were correlated with each other and with AER, respectively (r=0.67 for AGP; 0.35 for fibrinogen, and 0.41 for CRP, P<0.01 for all). Stepwise multiple regression analysis showed that AGP was independently associated with AER along with systolic blood pressure (r²=0.49, P=0.000). Logistic regression analysis showed that AGP was independently related to microalbuminuria with an odds ratio (95% CI) of 1.16 ((1.08–1.24), P=0.000). Conclusions: According to our results acute-phase proteins a known markers of chronic inflammation were associated with microalbuminuria independently of clinical cardiovascular disease. The influence of AGP on AER and microalbuminuria needs to be confirmed in prospective studies. Intervention studies are necessary to assess whether anti-inflammatory treatment would have a beneficial effect on this chronic complication of diabetes.

Abbreviations:  AER, albumin excretion rate, AGP, α₁-acid glycoprotein, CRP, C-reactive protein, FBG, fasting blood glucose, HbA1c, glycated hemoglobin, dBP, diastolic blood pressure, sBP, systolic blood pressure

Keywords:  Acute-phase proteins, Microalbuminuria, Type 2 diabetes