Prevalence of low glomerular filtration rate in the elderly population of Spain.: The PREV-ICTUS study

BACKGROUND AND OBJECTIVE: To assess the prevalence of low glomerular filtration rate (GFR < 60 l ml/min/1.73 m) in general population of subjects aged 60 years or older of Spain, and the related factors. PATIENTS AND METHOD: Analysis of PREV-ICTUS, a population-based study carried out in a sample of subjects aged 60 years or more, randomly selected and stratified by Autonomic Communities according to the census of inhabitants and the habitat in each Community. Demographic data, cardiovascular risk factors and diseases were collected. GFR was calculated using the MDRD (Modification of Diet in Renal Disease) equation. RESULTS: In 6,799 subjects (age 71.9 years-old; 53.6% women; 72.9% with arterial hypertension [HT]; 27.0% with diabetes mellitus [DM]; 24.3% with cardiovascular disease), 25.9% had low GFR (95% confidence interval, 24.8-26.9). The prevalence increased linearly, from 16.5% in subjects aged 60-64 years to 46.5% in those aged 85 or more (p < 0.001), and was higher in women (36.1% vs 14.1% in men, p < 0.001). In the multivariate analysis, low GFR was independently related to advanced age (odds ratio [OR] between 1.30 y 4.20), female gender (OR = 5.82), HT older than 7 years (OR = 1.23), uric acid (OR = 1.52 for each increment of 1 mg/dl) and cardiovascular disease (OR = 1.68). The association with DM did not reach statistical significance. In a model without cardiovascular disease, related factors remained the same, increasing the significance of HT older than 7 years (OR = 1.31) and of DM (OR = 1.19). CONCLUSION: One out or 4 subjects of this sample showed low GFR. The variables directly associated with low GFR were advanced age, female gender, HT of longer evolution, cardiovascular disease, increased uric acid, and, in one model, DM.