This study aims to investigate the influence of estimated glomerular filtration rate (eGFR) with two equations (and by one or two separate measurements), on the prevalence of chronic kidney disease (CKD) and its association with blood pressure, and cardiovascular and metabolic risk factors.
Between January 2010 and October 2011, the Ibermutuamur CArdiovascular RIsk Assessment project included 128 588 workers (77.2% men, mean age 39.3 years, range 16–75), who underwent two consecutive yearly medical check-ups and had information for eGFR according to the MDRD-IDMS and CKD-EPI equations (serum creatinine was measured by a isotope-dilution mass spectrometry traceable method in a single central laboratory). CKD was defined by an eGFR less than 60 ml/min per 1.73 m2. Subclinical (occult) renal disease was defined as an eGFR less than 60 ml/min per 1.73 m2 in patients with serum creatinine below 1.3 mg/dl and below 1.2 mg/dl in men and women, respectively.
In this working population, prevalence of CKD was very low, but two to six times lower when two separate eGFRs below 60 ml/min per 1.73 m2 were used. The prevalence of CKD was significantly lower with the CKD-EPI compared to the MDRD-IDMS equation. The same applies to occult CKD. In male workers, occult CKD was practically nonexistent.
Multivariate analyses show that blood pressure, total serum cholesterol, and serum glucose (positively), and high-density lipoprotein and low-density lipoprotein (negatively) were associated with CKD, with both equations. Another metabolic factor (waist circumference) was only associated (positively) with CKD defined by the CKD-EPI equation, which appears to be associated with most components of the metabolic syndrome.
The CKD-EPI formula, calculated on the basis of two reported blood samples, may provide the most specific definition of CKD.
aDepartment of Internal Medicine, University Hospital ‘Virgen de la Victoria’ and University of Málaga, Málaga
bIbermutuamur (Mutua de Accidentes de Trabajo y Enfermedades Profesionales de la Seguridad Social 274), Madrid
cDepartment of Internal Medicine, University of Santiago de Compostela
eHypertension Unit, 12 de Octubre Hospital, Madrid, Spain
fCentro Fisiologia Clinica e Ipertensione, University of Milan, and Istituto Auxologico Italiano, Milan, Italy
Correspondence to Miguel Angel Sánchez-Chaparro, Department of Internal Medicine, University Hospital ‘Virgen de la Victoria’ and University of Málaga, Málaga, Spain. Tel: +34 629175770; fax: +34 915765644; e-mail: firstname.lastname@example.org
Abbreviations: CI, confidence interval; CKD, chronic kidney disease; CKD-EPI equation, Chronic Kidney Disease-Epidemiology Collaboration equation; eGFR, estimated glomerular filtration rate; MDRD-4-IDMS equation, Modification of Diet in Renal Disease for Standardized Isotope-Dilution Mass Spectrometry Serum Creatinine equation; sCrs, erum creatinine
Received 12 November, 2013
Revised 12 May, 2014
Accepted 12 May, 2014