[Microalbuminuria and diabetic nephropathy. Detection and correlation with other degenerative complications]

Abstract

The prevalence of microalbuminuria and persistent proteinuria was studied in a population of 801 diabetic patients (535 with type II and 266 with type I diabetes). Urinary albumin excretion rate (AER) was measured on morning samples by laser nephelometry. Normoalbuminuria, as defined, in the absence of contaminated urine, by an albumin: creatinine (A/C) ratio below 2, was found in 551 patients, microalbuminuria (NC greater than or equal to 2 with AER below 200 mg/l) in 190 patients and persistent proteinuria (AER greater than or equal to 200 mg/l) in 60 patients. Microalbuminuria was present in 48 (18 p. 100) IDDM patients and 142 NIDDM patients. In IDDM patients, AER increased with the duration of the disease with no apparent influence of age at the onset. The prevalence of hypertension was 25 p. 100 and 61 p. 100 in IDDM patients with microalbuminuria and macroproteinuria respectively versus 10 p. 100 in patients with normoalbuminuria. This prevalence increased in NIDDM patients from 39.3 p. 100 with normoalbuminuria to 40.8 p. 100 and 76.2 p. 100 with microalbuminuria or macroproteinuria respectively. Proliferative retinopathy in type I and type II patients with normal AER was 7.4 p. 100 and 1.2 p. 100 respectively increasing to 15.2 p. 100 and 8.9 p. 100 with microalbuminuria and 27.8 p. 100 and 23.1 p. 100 with macroproteinuria. The prevalence of coronary disease increased from 4 to 10.4 p. 100 in patients with type I diabetes and microalbuminuria. The prevalence of cardiac failure increased from 1.5 to 2.1 p. 100 in type I diabetics and from 3.2 to 7.8 p. 100 in type II diabetics in the presence of microalbuminuria. Patients with microalbuminuria had increased levels of glycosylated hemoglobin A 1C but statistical difference was only obtained for patients with type II diabetes. Routine analysis of AER in diabetics allows early detection of diabetic nephropathy and emphasizes the need for tight metabolic and blood pressure control. Hypertension can be detrimental to nephropathy but might also initiate renal lesions in NIDDM patients.