Objective: To determine the prevalence and the associated features of microalbuminuria and overt proteinuria in Korean subjects with non-insulin-dependent diabetes mellitus (NIDDM) attending a hospital clinic.
Research design and methods: A total of 631 Korean outpatients with NIDDM were studied cross-sectionally for the presence of albuminuria and other micro- and macrovascular complications. Urinary albumin excretion rate (AER) was determined in timed overnight urine samples. Subjects were divided into three groups: no nephropathy (AER < 20 micrograms/min), microalbuminuria (AER 20-200 micrograms/min), and overt proteinuria (AER > 200 micrograms/min).
Results: Increased AER was present in 34% of our patients: 20% had microalbuminuria and 14% had overt proteinuria. Of patients with diabetes duration > or = 15 years, 35% had overt proteinuria. Most (82%) patients with overt proteinuria had retinopathy. Although the prevalence of microalbuminuria as a whole did not differ according to diabetes duration, the prevalence of microalbuminuria in the patients with retinopathy increased with diabetes duration. The microalbuminuric patients without retinopathy (diabetes duration < 5 years) were characterized by higher prevalence of hypertension and previous obesity, higher plasma triglyceride level, and lower plasma high-density lipoprotein cholesterol level.
Conclusions: The prevalence of overt proteinuria in Korean NIDDM patients with a long diabetes duration was higher than that reported in Caucasians. Our data also suggest that the clinical meaning of microalbuminuria may be different based on the presence or the absence of retinopathy. Microalbuminuria in patients with retinopathy most probably would reflect diabetic nephropathy. In contrast, some recent-onset NIDDM patients with microalbuminuria in the absence of retinopathy had features of syndrome X.