title: Low glomerular filtration rate in normoalbuminuric type 1 diabetic patients: an indicator of more advanced glomerular lesions.
abstract: Increased urinary albumin excretion rate is widely accepted as the first clinical sign of diabetic nephropathy. However, it is possible that some diabetic patients could first manifest reduced glomerular filtration rate (GFR) or hypertension. Relatively advanced diabetic renal lesions can be present in some diabetic patients with long-standing normoalbuminuria, and this might indicate increased risk of progression to microalbuminuria and then to overt diabetic nephropathy. The aim of this study was to identify a group of normoalbuminuric type 1 diabetic patients with low GFR and compare them with normoalbuminuric patients with normal GFR. Altogether, 105 normoalbuminuric type 1 diabetic patients with at least 10 years of diabetes duration that had a renal biopsy performed for research purposes were studied. Patients were divided according to GFR into groups with normal (>/=90 ml x min(-1) x 1.73 m(-2)) or reduced (<90 ml x min(-1) x 1.73 m(-2)) GFR. Clinical and renal structural parameters were compared between these two groups. Glomerular structural parameters were estimated by electron microscopic morphometry. The 23 patients with reduced GFR had more advanced diabetic glomerular lesions. The finding of reduced GFR was much more common among female patients, particularly if retinopathy and/or hypertension were also present. This report confirms that reduced GFR occurs among long-standing normoalbuminuric type 1 diabetic patients and is associated with more advanced diabetic glomerular lesions and, probably, with increased risk of progression. For these reasons, we suggest that regular measurements of GFR be performed in long-standing normoalbuminuric type 1 diabetic female diabetic patients, especially in those with retinopathy or hypertension.
authors.affiliation: Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: M Luiza
authors.initials: ML
authors.lastname: Caramori
authors.forename: Paola
authors.initials: P
authors.lastname: Fioretto
authors.forename: Michael
authors.initials: M
authors.lastname: Mauer
mesh_terms: D000328:Adult; D000419:Albuminuria; D001485:Basement Membrane / Q000473:pathology; D001706:Biopsy; D003922:Diabetes Mellitus, Type 1 / Q000473:pathology / Q000503:physiopathology*; D003928:Diabetic Nephropathies / Q000503:physiopathology*; D005260:Female; D005919:Glomerular Filtration Rate; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D006973:Hypertension / Q000150:complications; D007668:Kidney / Q000473:pathology; D007678:Kidney Glomerulus / Q000473:pathology / Q000503:physiopathology*; D008297:Male
chemical_list: D006442:Glycated Hemoglobin