[Prevalence of anemia, calcium-phosphorus abnormalities and metabolic acidosis in different stages of chronic renal failure].

BACKGROUND: Chronic kidney disease (CKD) is associated with the reduction of haemoglobin concentration and a variety of biochemical abnormalities including changes in serum concentration of sodium, potassium, calcium, phosphate, bicarbonate, and hydrogen ions. However, data concerning epidemiology of these abnormalities are rare and incomplete, especially among subjects with mild to moderate CKD.

PATIENTS AND METHODS: Patients with a serum creatinine concentration > 110 micromol/l hospitalized in the Department of Nephrology, Endocrinology and Metabolic Diseases Medical University of Silesia from 1998 to 2002 were analyzed. Patients with acute renal failure or chronic renal failure treated with renal replacement therapy were excluded from this study. A total of 653 patients (262F and 391M) were divided into 9 subgroups differing from each other by progressive decline of glomerular filtration rate (GFR).

RESULTS: A statistically significant decrease in haemoglobin concentration and increase in the prevalence of anaemia were found in patients with GFR < 50 ml/min. In a large number of patients with a GFR < 80 but > 50 ml/min, Hb concentration <11 g/dl was observed. Mean MCV, MCH and serum iron concentration were similar in all studied subgroups. A progressive increase in serum phosphorus concentration and decrease of calcaemia was found in patients with GFR < 30 ml/min. The elevated Ca x P product (> 4.44 mmol2/12) was noticed almost exclusively in patients with GFR< 30 ml/min. A decompensated metabolic acidosis was observed in 29.8% of patients with GFR <30 ml/min.

CONCLUSIONS: Anaemia is an early symptom of chronic kidney disease preceding disturbances of calcium, phosphate and hydrogen ions metabolism. These abnormalities seem to be of therapeutic relevance.