Urinary Albumin Excretion and Glomerular Filtration Rate across the Spectrum of Glucose Abnormalities in Essential Hypertension

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 > or =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 > or =3.4 mg/mmol (equivalent to > or =30 mg/g). The prevalence of abnormal UAE, > or =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 m2) 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 > or =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.