Normal values of glomerular filtration rate in geriatrics in Bandung and its correlation with serum cystatin-C levels

Full text: Determination of the normal values of glomerular filtration rate (GFR) is an essential part of the evaluation of patient with kidney disease. GFR almost linearly decreases with age at a mean annual rate of 0.8 ml/min/1.73 m2 over the age of 30 years old. According to NHANES III mean GFR for population with age > 60 years was 80 mL/min/1.73 m2. It is recommended for each centre to determine their own normal values of GFR for different age groups particularly in geriatric population. Recently, serum cystatin-C has been proposed as a new endogenous marker of glomerular filtration rate. Aim of the study was to determination of normal values of glomerular filtration rate (GFR) in geriatrics in Bandung and its correlation with serum Cystatin-C levels. Subjects were 24 males and 36 females (mean age 66.71 ± 6.7 years; range 60-87 yrs), without any renal and/or systemic disease. Creatinine clearance was estimated by using Cockroft-Gault formula and serum cystatin-C level were determined by using particle enhanced immunonephelometric method, while GFR values were determined by external body counting methods using Tc-99m DTPA ( Gates' methods ). Pearson correlation was used to determine correlation between variables and a P value < 0.05 is considered significant. Results and Discussion. Mean total GFR was 67.57 ml/min/1.73 m2 (SD ± 16.02), range from 45 to 100 ml/min/1.73 m2. Mean total GFR for male was 69.46 ml/min/1.73 m2, and female was 66.31 ml/min/1.73 m2, the difference was statistically significant (p < 0.05). The results were lower than NHANES III values. There was a better correlation between total GFR and cystatin-C level (r = -0.522 and p < 0.001) compared to total GFR and creatinine clearance (r 0.306 and p < 0.005). Mean creatinine clearance was 57.93 ml/min and serum cystatin-C was 0.97 mg/dl, the correlation was statistically significant (r -0.414 and p < 0.005). Conclusions: The normal values of GFR in geriatric population in Bandung were 69.46 ml/min/1.73 m2 for male (SD ± 16.02) and 66.30 ml/min/1.73 m2 for female (SD ± 19 ) respectively. The correlation between GFR, cystatin-C level and creatinine clearance were statistically significant. (author)