Evidence that even "normal" albuminuria may denote incipient GFR reduction in patients with type 2 diabetes mellitus.

AIMS: In patients with diabetes and microalbuminuria, small changes of GFR could have been missed, due to the lack of sensitive methodology for GFR determination in clinical practice (creatinine based calculations). Therefore we explored the relation of the degree of albumin excretion with Cystatin C, which has been recently proved to be a better marker of GFR, compared to serum creatinine. METHODS: We studied 179 patients with type 2 diabetes, in whom renal function and microalbuminuria were evaluated. RESULTS: In patients with normal renal function, GFR/MDRD>or=60 ml/min/1.73 m(2), (n=79), urinary albumin concentration (UAC) was significantly correlated with Cystatin C, both in patients with normoalbuminuria (r=0.547, p<0.023) or microalbuminuria (r=0.305, p<0.035), while it was not correlated either with serum creatinine or calculated creatinine clearance. In patients with GFR/MDRD<60 ml/min/1.73 m(2), (n=100), UAC was significantly correlated with Cystatin C, also both in patients with normoalbuminuria (r=0.536, p<0.032) or microalbuminuria (r=0.340, p<0.016), while it was significantly correlated with serum creatinine and calculated creatinine clearance only in those with microalbuminuria. CONCLUSIONS: Subtle changes in renal function, as judged by Cystatin C concentration, may parallel the degree of albuminuria, even in the normoalbuminuric stage. This finding needs further confirmation by more appropriate methodology in prospective follow up studies.

Plasma lipids and urinary albumin excretion rate in Type 1 diabetes mellitus: the EURODIAB IDDM Complications Study.

AIMS: To examine the relationship between increased urinary albumin excretion rate and fasting plasma lipids among male and female respondents to the EURODIAB IDDM Complications Study, and attempt to explain inconsistencies in previous reports. METHODS: A cross-sectional study of 3250 randomly selected Type 1 diabetic patients from 31 diabetes clinics in 16 European countries was carried out between 1989 and 1990. Plasma lipids and urinary albumin were measured centrally. The present analysis was confined to the subgroup of 2205 patients attending after a 10-12 h overnight fast. Mean age was 33 years (SD 10) and mean duration of Type 1 diabetes mellitus was 15 years (SD 9). RESULTS: The prevalence of microalbuminuria (24-h urinary albumin excretion rate 20-200 microg/min) was 21.7% (95% confidence interval 19.9-23.5) and macroalbuminuria (24-h urinary albumin excretion rate > 200 microg/min) 7.8% (6.6-9.0). In comparison to patients with normal urinary albumin excretion rate (< 20 microg/min), and after controlling for age, sex, glycaemic control, duration of diabetes and current smoking, macroalbuminuria was associated with significantly (P<0.01) increased fasting plasma triglycerides, cholesterol, LDL-cholesterol, cholesterol:HDL-cholesterol ratio and, in women, reduced HDL-cholesterol. In men and women with microalbuminuria, the only significant association was with increased plasma triglycerides. CONCLUSIONS: These data confirm that there is an association between fasting plasma lipids and increasing urinary albumin excretion rate in European Type 1 diabetic patients. In microalbuminuric patients, however, the association was weaker than previously reported and partly explained by confounding factors.