Lowering the threshold for defining microalbuminuria: effects of a lifestyle-metformin intervention in obese "normoalbuminuric" non-diabetic subjects.
BACKGROUND
We investigated whether levels of albuminuria (urinary albumin excretion (UAE)) below those conventionally accepted as microalbuminuria (<30 mg/day) are sensitive to correction of obesity and obesity-related risk factors.


METHODS
The effects of a 12-month lifestyle modification-metformin program were evaluated in otherwise healthy overweight/obese "normoalbuminuric" subjects: group I with UAE of <10 mg/day (n = 23) and group II with UAE of 10-29 mg/day (n = 18).


RESULTS
The subjects of group II were older and heavier, and had higher blood pressure (BP) and lower high-density lipoprotein (HDL) levels, than those of group I. Creatinine clearances were also higher in group II (148 +/- 14 ml/min) than in group I (108 +/- 9 ml/min). Although the intervention induced comparable reductions in obesity, BP, lipids and insulin levels in both groups, UAE was significantly reduced in group II (9.1 +/- 1.8 mg/24 h; 60% reduction; P < 0.001), and non-significantly in group I (0.75 +/- 0.5 mg/day; 12% reduction; P > 0.1). Additionally, greater reduction in creatinine clearance was observed in subjects with higher UAE rates. After the intervention, both groups achieved similar UAE rates (5.7 +/- 0.9 and 5.2 +/- 1.0 mg/day; P > 0.10). Basal UAE was related to the subjects' creatinine clearance (r = 0.38; P = 0.04). For both groups together, intervention-induced changes in UAE rates were not significantly related to BP, age, or body weight. However, for group II subjects, BP and UAE reduction were positively associated (r = 0.44; P = 0.03).


CONCLUSIONS
UAE of 10-29 mg/day (hyperalbuminuria), below the conventionally used limit to define microalbuminuria, is already associated with a more adverse cardiovascular risk profile, and is exquisitely sensitive to interventions that reduce obesity, BP, and insulin resistance.
Cubeddu
Luigi X
LX
Center for the Detection and Treatment of Silent Risk Factors for Metabolic and Cardiovascular Disease, Division of Clinical Pharmacology, School of Pharmacy, Central University of Venezuela, Caracas, Venezuela. lcubeddu@nova.edu
Alfieri
Anna B
AB
Hoffmann
Irene S
IS
D000328:Adult; D000419:Albuminuria / Q000097:blood / Q000145:classification / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D001794:Blood Pressure / Q000187:drug effects; D031204:Caloric Restriction; D002318:Cardiovascular Diseases / Q000097:blood / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D003404:Creatinine / Q000097:blood; D015444:Exercise; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007333:Insulin Resistance; D008019:Life Style; D008055:Lipids / Q000097:blood; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000150:complications / Q000178:diet therapy / Q000188:drug therapy / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome; D015431:Weight Loss
D007004:Hypoglycemic Agents; D008055:Lipids; D008687:Metformin; D003404:Creatinine