Introduction:
Chronic kidney disease (CKD) affects up to 10% of modern societies and its prevalence increases with age. In most epidemiological reports CKD is diagnosed based mainly or exclusively on estimated glomerular filtration rate (eGFR) assessment. Since no ‘‘gold standard’’ or reference method of eGFR calculation exists and other diagnostic criteria of CKD are rarely employed, the true prevalence of clinically significant CKD seems to be lower than reported in large epidemiological studies.

Aim:
We aimed to analyze the prevalence of CKD and its clinical significance in the cohort of patients aged 65 years and older in general practice, applying all recommended criteria.

Material and methods:
108 consecutive patients (40 men and 68 women) aged 65 years and older (mean age 72 ± 5.2 years; range 65–87 years) were analyzed. Biochemical tests available in general practice with eGFR calculation using modification of diet in renal disease (MDRD), CKD epidemiology collaboration (CKD-EPI), Cockcroft–Gault formula and renal ultrasound were performed.

Results and discussion:
50% of patients were characterized with significantly reduced MDRD/CKD-EPI-eGFR (<60 mL/min/1.73 m²). Detailed analysis revealed that patients with low eGFR do not differ from those with eGFR more than or equal to 60 mL/min/1.73 m² in terms of serum biochemical parameters (except for urea and creatinine), proteinuria/albuminuria, urinalysis, renal ultrasound, blood pressure or history of cardiovascular disease.

Conclusions:
Stage 3 CKD (eGFR < 60 mL/min/1.73 m²) in patients aged 65 years or older seems to be a ‘‘benign’’ finding with no important clinical consequences. It should be emphasized that these results apply to ambulant elderly patients with relatively low co-morbidities.