The prevalence of chronic kidney disease (CKD), especially the early stages, is still not exactly known. This is also true for CKD stage 3, when cardiovascular and other major complications generally appear. The NANHES data have shown a steady increase in the prevalence of CKD 3 up to 7.7% in 2004. Chronic kidney disease and renal failure are underdiagnosed all over the world. In Italy, prevalence estimates for stage 3 to 5 CKD are around 4 million yet, less than 30% of these subjects are believed to be followed at nephrology clinics. This means that in Italy for every dialyzed patient there are about 85 individuals with possibly progressive kidney disease, while fewer than five (mainly stage 4 and 5 patients) are actually followed by a nephrologist.