SERUM SIALIC-ACID CONCENTRATION IS ELEVATED IN IDDM ESPECIALLY IN EARLY DIABETIC NEPHROPATHY

Objectives, Elevated serum sialic acid concentration is a strong predi ctor of cardiovascular mortality in non-diabetic subjects, Because pat ients with insulin-dependent diabetes mellitus (IDDM) and albuminuria have a highly increased cardiovascular morbidity and mortality, we hyp othesized that IDDM patients with albuminuria would have an increased concentration of serum sialic acid, Design, Cross-sectional study. Set ting, Outpatient clinic at Steno Diabetes Centre, Gentofte, Denmark, S ubjects, Twenty-six non-diabetic controls and 74 IDDM patients with no rmoalbuminuria (urinary albumin excretion [UAE] < 30 mg 24 h(-1); n = 37), incipient nephropathy (UAE 30-300 mg 24 h(-1); n = 20) and clinic al nephropathy (UAE > 300 mg 24 h(-1); n = 17), matched for sex, age a nd body mass index (BMI), Main outcome measures, Serum sialic acid con centration, concurrent fasting blood glucose, glycated haemoglobin (Hb A1c), serum creatinine, plasma fibrinogen and erythrocyte sedimentatio n rate, Results, Normoalbuminuric patients had a higher serum sialic a cid concentration (mmol L(-1)) than non-diabetic controls (1.83 +/- 0. 24 vs, 1.67 +/- 0.26; P < 0.02). Serum sialic acid concentration was f urther increased in patients with incipient nephropathy (2.02 +/- 0.37 ; P < 0.03) and in patients with clinical nephropathy (2.13 +/- 0.33; P < 0.002) compared with normoalbuminuric IDDM patients, Serum sialic acid correlated strongly with plasma fibrinogen (r = 0.78; P < 0.0001) and erythrocyte sedimentation rate (r = 0.62; P < 0.0001). In a multi ple regression analysis including UAE, retinopathy status, fasting blo od glucose, HbA1c, mean blood pressure, serum creatinine, age, BMI, du ration and smoking, UAE and fasting blood glucose were the independent variables which correlated significantly with serum sialic acid conce ntration (P < 0.0001 and P < 0.05, respectively), Conclusion, Serum si alic acid is elevated in IDDM especially in albuminuric patients. Whet her elevated serum sialic acid is predictive for early diabetic nephro pathy and cardiovascular disease in IDDM has to be shown in the future .