Renal potassium excretion: comparison between chronic renal disease patients and old people.
Senescence and chronic renal failure bring about a progressive glomerular filtration reduction. Moreover, a reduction in glomerular filtration usually modifies the potassium renal excretion. In the present study, we compared the renal potassium handling between old and chronic renal disease populations.


METHODS
Fifty-five volunteers were studied, 43 of them were healthy old persons and 12 were predialysis chronic renal disease patients. Exclusion criteria were: presence of altered plasma potassium (Kp), diabetes mellitus, obstructive uropathy, drugs that could alter plasma potassium levels. All volunteers were on a diet with a potassium content around 50 mmol/day (3-day dietary register). We measured potassium, creatinine, urea in plasma and 24 hours urine. We also measured creatinine clearance (CrCl) and fractional excretion of potassium (FEK), and we studied the relationship between these parameters. Statistical analysis was made using Student's test.


RESULTS
Slopes of the correlation curves between CrCl and FEK. [Table: see text].


CONCLUSIONS
The relationship between creatinine clearance and fractional excretion of potassium in old and chronic renal disease groups were different with the excretion of potassium being lower in the elderly.
Musso
C G
CG
Nephrology Department, Hospital Italiano de Buenos Aires, Argentina. carlos.musso@hospitalitaliano.org.ar
Miguel
R de
Rd
Algranati
L
L
Farias
E Dos Ramos
Edos R
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002908:Chronic Disease; D003404:Creatinine / Q000652:urine; D005919:Glomerular Filtration Rate; D006801:Humans; D007674:Kidney Diseases / Q000378:metabolism / Q000652:urine*; D008875:Middle Aged; D011188:Potassium / Q000652:urine*
D003404:Creatinine; D011188:Potassium