title: Hyperfiltration in patients with type I diabetes mellitus: a prevalence study.
abstract: OBJECTIVE
  An increase in glomerular filtration rate (GFR) and renal plasma flow (EFPR) may be considered as prognostic factors for the progression of diabetic nephropathy; however the real predicting value of hyperfiltration in the development of incipient and overt nephropathy is as yet unknown. We have examined the prevalence of hyperfiltration in a population of normotensive adult IDDM patients and the possible effect of long-term metabolic control on glomerular hemodynamics.
  
  
  METHODS
  We measured GFR and ERPF values in 177 normotensive, normoalbuminuric insulin-dependent diabetic patients and in 30 healthy subjects by single bolus intravenous injection of 1 miroCu/kg [51Cr]-EDTA and 0.2 microCu/kg [125I]-Hippuran intravenously. We have correlated the GFR values with parameters of metabolic control over the last 3 years and with age, sex, and duration of diabetes.
  
  
  RESULTS
  Patients with a GFR greater than the 95 degrees percentile value of controls (135 ml/min/1,73 m2) were defined as hyperfiltering. They represented the 55.9% (99/177) of our population. We found a strong correlation between GFR and ERPF (p <0.001), and between GFR and average HbA1c levels (p = 0.016) in multiple regression analysis, with age, sex, ERPF, and average HbA1c levels entered as variables (r2 = 0.45). There appeared to be no correlation with the duration of the disease.
  
  
  CONCLUSIONS
  Long-term hyperglycemia provides a significant contribution in GFR and a poor metabolic control is predictive of overt nephropathy. In this study hyperfiltration does not appear to be the major factor of diabetic nephropathy. A follow-up of these patients is necessary to clarify the role of hyperfiltration in the development of overt nephropathy in diabetes.
authors.affiliation: Department Internal Medicine and Geriatric, Università Cattolica del Sacro Cuore, Roma, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Cotroneo
authors.forename: A
authors.initials: A
authors.lastname: Manto
authors.forename: L
authors.initials: L
authors.lastname: Todaro
authors.forename: A
authors.initials: A
authors.lastname: Manto
authors.forename: D
authors.initials: D
authors.lastname: Pitocco
authors.forename: C
authors.initials: C
authors.lastname: Saponara
authors.forename: C
authors.initials: C
authors.lastname: Vellante
authors.forename: M L
authors.initials: ML
authors.lastname: Maussier
authors.forename: G
authors.initials: G
authors.lastname: D'Errico
authors.forename: P
authors.initials: P
authors.lastname: Magnani
authors.forename: G
authors.initials: G
authors.lastname: Ghirlanda
mesh_terms: D000328:Adult; D000367:Age Factors; D002860:Chromium Radioisotopes; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism / Q000503:physiopathology* / Q000517:prevention & control; D003928:Diabetic Nephropathies / Q000209:etiology / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006442:Glycated Hemoglobin / Q000032:analysis; D006439:Hemodynamics; D006801:Humans; D006943:Hyperglycemia / Q000503:physiopathology / Q000517:prevention & control; D007457:Iodine Radioisotopes; D007678:Kidney Glomerulus / Q000503:physiopathology; D008297:Male; D015995:Prevalence; D011379:Prognosis; D019275:Radiopharmaceuticals; D012044:Regression Analysis; D017595:Renal Plasma Flow / Q000502:physiology*; D012737:Sex Factors; D013997:Time Factors
chemical_list: D002860:Chromium Radioisotopes; D006442:Glycated Hemoglobin; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals