OBJECTIVES: To validate the Cockroft-Gault and the abbreviated Modification of Diet in Renal Disease (MDRD) formulas in a hypertense population aged over 60 and with blood pressure monitored in out-patients. To evaluate the prevalence of various stages of hidden chronic kidney disease in this population. DESIGN: Descriptive study of validation of diagnostic tests. SETTING: Urban primary care centre. PARTICIPANTS: A total of 113 patients over 60 (53.8% female) with hypertension and no history of chronic kidney disease, on whom blood pressure could be monitored in a 24-hour session. MAIN MEASUREMENTS: Calculation of the glomerular filtration rate. Validity parameters of diagnostic tests. RESULTS: Renal clearance estimated in the Cockroft-Gault and MDRD equations was similar (77.9 mL/min and 76.9 mL/min, respectively). There was 37.3% prevalence of chronic kidney disease, using the Cockroft-Gault equation; and 27.0%, using the MDRD. The degree of agreement between the two equations was excellent in classifying patients with stage-2 chronic kidney disease (kappa index =0.9) and it was acceptable for stage-3 (kappa index =0.5). In both equations, validity indexes were acceptable for the presence of microalbuminuria as a manifestation of renal damage. CONCLUSIONS: There is a high prevalence of hidden chronic kidney disease in the hypertense population over 60 years old. Glomerular filtration should be determined systematically in these patients, even when their plasma creatinine figures are normal.
OBJECTIVES: To validate the Cockroft-Gault and the abbreviated Modification of Diet in Renal Disease (MDRD) formulas in a hypertense population aged over 60 and with blood pressure monitored in out-patients. To evaluate the prevalence of various stages of hidden chronic kidney disease in this population. DESIGN: Descriptive study of validation of diagnostic tests. SETTING: Urban primary care centre. PARTICIPANTS: A total of 113 patients over 60 (53.8% female) with hypertension and no history of chronic kidney disease, on whom blood pressure could be monitored in a 24-hour session. MAIN MEASUREMENTS: Calculation of the glomerular filtration rate. Validity parameters of diagnostic tests. RESULTS: Renal clearance estimated in the Cockroft-Gault and MDRD equations was similar (77.9 mL/min and 76.9 mL/min, respectively). There was 37.3% prevalence of chronic kidney disease, using the Cockroft-Gault equation; and 27.0%, using the MDRD. The degree of agreement between the two equations was excellent in classifying patients with stage-2 chronic kidney disease (kappa index =0.9) and it was acceptable for stage-3 (kappa index =0.5). In both equations, validity indexes were acceptable for the presence of microalbuminuria as a manifestation of renal damage. CONCLUSIONS: There is a high prevalence of hidden chronic kidney disease in the hypertense population over 60 years old. Glomerular filtration should be determined systematically in these patients, even when their plasma creatinine figures are normal.