Correlation between creatinine clearance and transtubular potassium concentration gradient in old people and chronic renal disease patients

• Published in: Saudi journal of kidney diseases and transplantation Vol. 18; no. 4; pp. 551 - 555
• Main Authors: Musso, Carlos, Liakopoulos, Vassilis, Stefanidis, Ioanis, De Miguel, Raul, Imperiali, Nora, Algranati, Luis
• Format: Journal Article
• Language: English
• Published: Saudi Arabia Medknow Publications and Media Pvt. Ltd 01.11.2007
• Subjects: Aged; Aged, 80 and over; Chronic kidney failure; Creatinine - metabolism; Glomerular Filtration Rate; Humans; Kidney Failure, Chronic - blood; Kidney Failure, Chronic - urine; Kidney Tubules - metabolism; Middle Aged; Osmolar Concentration; Potassium - metabolism; Severity of Illness Index
• ISSN: 1319-2442

Senescence and chronic kidney disease (CKD) reduce progressively glomerular filtration rate (GFR), which usually results in an increase in potassium renal secretion. To evaluate whether the transtubular potassium concentration gradient (TTKG) is more accurate parameter for evaluating the renal secretion of this cation than using fractional excretion of potassium as its urinary secretion marker, we studied 55 subjects, 43 of them were healthy elderly volunteers and 12 were CKD patients. Exclusion criteria were: abnormal plasma potassium level or presence of any disease or drug that could induce alteration of balance of this electrolyte levels. All the subjects were on a diet with a potassium content around 50 mmol/day. The curves, which demonstrate the relationship between creatinine clearance and TTKG and the grade of correlation between these two parameters were analyzed in both groups. We found that the transtubular potassium concentration gradient had a significant negative correlation with the creatinine clearance level in the healthy elderly group, while there was no correlation in the CKD group.