Persistent Renal Hypertrophy and Faster Decline of Glomerular Filtration Rate Precede the Development of Microalbuminuria in Type 1 Diabetes
- Gianpaolo Zerbini1,
- Riccardo Bonfanti2,
- Franco Meschi2,
- Emilio Bognetti2,
- Pier Luigi Paesano3,
- Luigi Gianolli4,
- Marialuisa Querques1,
- Anna Maestroni1,
- Giliola Calori5,
- Alessandro Del Maschio6,
- Ferruccio Fazio4,
- Livio Luzi1 and
- Giuseppe Chiumello6
- 1Renal Pathophysiology Unit, Section Nutrition-Metabolism, Department of Medicine, Istituto Scientifico San Raffaele, Milan, Italy
- 2Endocrine Unit, Department of Pediatrics, Istituto Scientifico San Raffaele, Milan, Italy
- 3Department of Radiology, Istituto Scientifico San Raffaele, Milan, Italy
- 4Division of Nuclear Medicine, Istituto Scientifico San Raffaele, Milan, Italy
- 5Epidemiology Unit, Istituto Scientifico San Raffaele, Milan, Italy
- 6Universitá Vita-Salute San Raffaele, Milan, Italy
- Address correspondence and reprint requests to Dr. Gianpaolo Zerbini, Department of Medicine, San Raffaele Scientific Institute, Via Olgettina, 60, I-20132 Milan, Italy. E-mail: g.zerbini{at}hsr.it
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 m2, 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.
Footnotes
-
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
- Accepted June 15, 2006.
- Received May 2, 2006.
- DIABETES
