title: Persistent renal hypertrophy and faster decline of glomerular filtration rate precede the development of microalbuminuria in type 1 diabetes.
abstract: Soon after the onset of type 1 diabetes, renal hypertrophy and hyperfiltration become manifest, particularly among patients who will subsequently develop diabetic nephropathy. Whether these early renal dysfunctions are involved in the pathogenesis of diabetic nephropathy is currently unclear. We evaluated, during the same day, kidney volume and glomerular filtration rate (GFR) in 146 patients with type 1 diabetes and normal renal function. All the individuals were then monitored for a mean of 9.5 +/- 4.4 years for the development of microalbuminuria. Kidney volume and GFR were reevaluated in a subset of 68 patients 4 years after baseline. During follow-up, microalbuminuria developed in 27 of 146 diabetic patients. At baseline, kidney volume (312.8 +/- 52.6 vs. 281.4 +/- 46.1 vs. 236.8 +/- 41.6 ml/1.73 m(2), P < 0.05) but not GFR was increased in patients predisposed to microalbuminuria. Risk of progression was higher in patients with increased kidney volume (P = 0.0058). Patients predisposed to microalbuminuria showed a stable increase in kidney volume (P = 0.003), along with a faster decline of GFR (P = 0.01). Persistent renal hypertrophy and faster decline of GFR precede the development of microalbuminuria in type 1 diabetes. These findings support the hypothesis that renal hypertrophy precedes hyperfiltration during the development of diabetic nephropathy.
authors.affiliation: Department of Medicine, San Raffaele Scientific Institute, Via Olgettina, 60, I-20132 Milan, Italy. g.zerbini@hsr.it
authors.forename: Gianpaolo
authors.initials: G
authors.lastname: Zerbini
authors.forename: Riccardo
authors.initials: R
authors.lastname: Bonfanti
authors.forename: Franco
authors.initials: F
authors.lastname: Meschi
authors.forename: Emilio
authors.initials: E
authors.lastname: Bognetti
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Paesano
authors.forename: Luigi
authors.initials: L
authors.lastname: Gianolli
authors.forename: Marialuisa
authors.initials: M
authors.lastname: Querques
authors.forename: Anna
authors.initials: A
authors.lastname: Maestroni
authors.forename: Giliola
authors.initials: G
authors.lastname: Calori
authors.forename: Alessandro
authors.initials: A
authors.lastname: Del Maschio
authors.forename: Ferruccio
authors.initials: F
authors.lastname: Fazio
authors.forename: Livio
authors.initials: L
authors.lastname: Luzi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Chiumello
mesh_terms: D000293:Adolescent; D000419:Albuminuria / Q000209:etiology*; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D003928:Diabetic Nephropathies / Q000209:etiology; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D006984:Hypertrophy; D007668:Kidney / Q000473:pathology*; D008297:Male