Urine protein excretion among Chinese patients with type 2 diabetes mellitus

Urinary excreton of low molecular weight proteins such as beta2-microglobulin and retinol binding protein (RBP), and enzymes such as N-acetyl-beta-D-glucosaminidase (NAG), may be useful as indicators of renal tubular dysfunction in diabetes mellitus.

To describe the profile of urinary protein and enzyme excretion in 240 Chinese patients with type 2 diabetes mellitus in Singapore.

Cross-sectional study of consecutive patients presenting for follow-up at a Government primary care clinic. Information was obtained from interview, physical examination and laboratory analysis. Data analysis included descriptive statistics on urinary protein and enzyme excretion, comparison of unadjusted and adjusted means of these among patient subgroups, as well as correlation with control of diabetes and other clinical parameters.

Albuminuria correlated with urine beta2-microglobulin (r=0.34, p<0.01) and RBP (r=0.46, p<0.01). Hypertensive patients had significantly higher mean urine albumin (geometric mean 15.13 mg/gCr) and beta2-microglobulin (363.18 microg/gCr) levels compared to patients without hypertension (7.07 mg/gCr; 219.20 microg/gCr; p<0.05). Patients with complications of diabetes also had higher albumin (15.55 vs 6.20 mg/gCr), beta2-microglobulin (344.47 vs 288.83 microg/gCr) and RBP excretion (152.02 vs 94.54 mg/gCr). Two-hour postprandial sugar correlated with beta2-microglobulin (r=0.33, p<0.01), RBP (r=0.35, p<0.01) and NAG (r=0.28, p<0.01). Urinary protein excretion did not correlate with HbA1c, fasting blood sugar, age of patient or duration since diagnosis.

These results among 240 Chinese patients in Singapore were consistent with reports from other study populations.