Cross-sectional survey of the prevalence of reduced estimated glomerular filtration rate, albuminuria and cardiovascular risk in a native Spanish population

Objectives: HERMEX is a population-based study which tries to evaluate the relative weight of cardiovascular risk factors in inhabitants of Extremadura, Spain. This report presents the data about chronic kidney disease (CKD) in a Spanish population sample. Methods: For an observational cross-sectional population-based study, 3,402 subjects were randomly selected from health care system records. The final sample included 2,813 participants (mean age 51.2 years, 53.5% women). Renal function was estimated from serum creatinine using the 4-variable Modification of Diet in Renal Disease (MDRD-4) Study and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations. Individual renal risk was calculated using the Kidney Disease Improving Global Outcomes (KDIGO) table. Results: Using the CKD-EPI formula, 3.6% of participants had a glomerular filtration rate (GFR) < 60 ml/min. MDRD-4 gave a result of 4.0%. Prevalence of albuminuria was 5.5%. Taken together, in patients with albuminuria and/or reduced GFR, the prevalence of renal disease was 8.1%. The KDIGO renal risk table suggested that 0.05% of patients were at high or very high risk of CKD progression and 1.6% at medium risk. CKD was more common in those who were obese, hypertensive, dyslipidemic or had diabetes. Multivariate analysis showed an independent negative association of CKD as dependent variable with systolic blood pressure and body mass index, but a positive correlation with diastolic blood pressure and male sex. Conclusions: A low frequency of abnormal GFR was detected in a randomly selected sample of the Spanish general population. This finding agreed with the low rates of cardiovascular mortality and morbidity observed in Spain in spite of a high prevalence of classic cardiovascular risk factors.