Urinary Albumin Excretion and Glomerular Filtration Rate across the Spectrum of Glucose Abnormalities in Essential Hypertension Josep Redon,* Francisco Morales-Olivas, † Alberto Galgo, ‡ Miguel A ´ ngel Brito, § Javier Mediavilla,  Rafael Marı ´n, ¶ Pilar Rodrı ´guez,** Salvador Tranche, †† Jose ´ Vicente Lozano, ‡‡ Claudia Filozof; §§ and the MAGAL Group *Internal Medicine Service, Hospital Clı ´nico, and † Department of Pharmacology, University of Valencia, Valencia, ‡ Centro de Salud Espronceda and § Endocrinology, Hospital Puerta de Hierro, Madrid,  Centro de Salud Pampliega, Burgos, ¶ Nephrology Service, Hospital Universitario Central de Asturias, Oviedo, **Fingoi Health CareCentre, Lugo, †† El Cristo Health Centre, Oviedo, ‡‡ Centro de Salud Serrerı ´a 2, Valencia, and §§ Scientific Department, Cardiovascular Section, Bristol-Myers-Squibb, Madrid, Spain The objective of this study was to assess the relationship between urinary albumin excretion (UAE) and GF across the spectrum of the glucose metabolism abnormalities in a large population of patients with hypertension. The Microaluminuria en Pacientes con Glucemia Basal Alterada (MAGAL) is a multicenter, cross-sectional study that was carried out by 1723 primary care physicians. A total of 6227 patients with essential hypertension (in three groups: [1] normal fasting glucose <100 mg/dl, [2] impaired fasting glucose >100 to 126 mg/dl, and [3] type 2 diabetes) were analyzed in this substudy. GFR was estimated by using the Modification of Diet in Renal Disease (MDRD) abbreviated equation. A single first-morning urine albumin/creatinine ratio was measured using Bayer reagent strip Microalbustix, a semiquantitative method. Abnormal UAE was defined as an albumin/creatinine ratio >3.4 mg/mmol (equivalent to >30 mg/g). The prevalence of abnormal UAE, >3.4 mg/mmol, increased across the spectrum of glucose abnormalities: 39.7, 46.2, 48.6, and 65.6% for normoglycemic, low-range, and high-range impaired fasting glucose and diabetes, respectively. UAE was positively related to SBP (P  0.003) and inversely to GFR (P < 0.001). Renal insufficiency (GFR <60 ml/min per 1.73 m 2 ) was present in 21.8% of the patients, more frequently older patients, women, and those with diabetes. The factors that were related to renal insufficiency were UAE >3.4 mg/mmol (odds ratio 1.86; 95% confidence interval 1.60 to 2.17) and diabetes (odds ratio 1.62; 95% confidence interval 1.29 to 2.04). There is a close relationship between abnormal UAE and renal insufficiency in essential hypertension. This is more marked in patients with diabetes and moderate in patients with high-range impaired fasting glucose. J Am Soc Nephrol 17: S236 –S245, 2006. doi: 10.1681/ASN.2006080920 A n increase in urinary albumin excretion (UAE) even to a small extent, microalbuminuria, has become a marker for cardiovascular and renal disease. Initially tested in diabetes, its prognostic value in hypertensive patients without diabetes and in subgroups of the general population has been well established during the past few years (1–11). In both patients with diabetes and without diabetes, elevated SBP and glucose levels are the main factors related to develop- ment of increased UAE. One of the largest epidemiologic stud- ies, the Australian Diabetes Obesity and Lifestyle Study (Aus- Diab) (12), clearly showed the interaction of both factors in the prevalence of microalbuminuria. The relationship between UAE and estimated GFR, however, has received less attention even though GFR, like UAE, is a predictor of cardiovascular risk. Widespread use of formulas to calculate GFR has enabled the influence of renal function in cardiovascular risk to be assessed. Therefore, alterations in renal function have emerged as a pre- dictive marker for cardiovascular disease, and it has been re- flected as such in the guidelines for clinical management (13,14). Several studies have shown calculated GFR to be a risk indicator for general mortality and cardiovascular death after myocardial infarction (15–20) and also for mortality associated with heart failure (21). Likewise, a large health registry has revealed a gradual relationship between estimated GFR and the risk for death, cardiovascular events, and hospitalization, inde- pendent of other risk factors (22). Microalbuminuria and renal insufficiency frequently run in parallel (23). Both of them are influenced by BP and glucose levels. Whereas BP is the major determinant of microalbumin- uria, glucose level is the major determinant of renal insuffi- ciency (23). Despite the frequent cluster of microalbuminuria and low GFR, the potential interaction between UAE and GFR is not well understood even though it can provide useful clin- ical information. Therefore, the objective of the present study was to analyze the relationship between UAE and GFR across Address correspondence to: Dr. Josep Redon, Hypertension Clinic, Internal Med- icine, Hospital Clinico, University of Valencia, 46010 Valencia, Spain. Phone: +34-963862647; Fax: +34-963862647; E-mail: josep.redon@uv.es Copyright © 2006 by the American Society of Nephrology ISSN: 1046-6673/1712-0236