Objective To evaluate the potential role of Serum Cystatin C (Scys) for glomerular filtration rate (GFR) of very old patients with chronic kidney disease (CKD).
Methods 50 male CKD patients who were above 75 years old in our hospital were selected for detecting GFR by nephrogram using 99mTc-DTPA. Meanwhile, the concentrations of serum creatinine (Scr) and Scys were tested. eGFR were calculated by the equations of Cockcroft-Gault (CG), simplified Chinese Modification of Diet in Renal Disease equations for Scr, and the equations of Hoek, Le Bricon for Scys respectively. The results were analysed statistically.
Results All patients were diagnosed to CKD stage 3 to stage 5 according to the results of GFR by nephrogram. The concentration of Scys was not effected by age, weight and height (p>0.05), and the average concentration of Scys had significant difference among stage 3, 4, and 5 of CKD patients (p<0.05). For Scys and the equations of Hoek and Le Bricon, their correlation coefficients to GFR were higher than those of Scr and the equations of CG, Chinese simplified Modification of Diet in Renal Disease in stage 5 CKD patients, but lower in stage 3 and 4 CKD patients (p<0.05).
Conclusions The evaluation accuracy of GFR using Scys were not concordant in different stage of very old CKD patients. Whether Scys was the better marker for evaluating GFR of very old CKD patients needed future researching.