[Clinical significance of urinary methylguanidine in non-dialyzed patients with chronic renal failure--prediction of progression rate of renal dysfunction].

To clarify a clinical significance of urinary methylguanidine (U-MG, micrograms/dl) in non-dialyzed patients with chronic renal failure, we measured U-MG, urinary creatinine (U-Cr, mg/dl) and serum creatinine (S-Cr, mg/dl), concurrently and continually in 36 out-patients whose S-Cr was over 4.0 mg/dl. Fresh urine sample was obtained and U-MG was measured by an enzymic method. S-Cr concentrations (mean +/- SD) at the initiation of dialysis therapy were comparable in non-diabetics and in diabetics, being 13.4 +/- 4.54mg/dl and 8.23 +/- 1.96mg/dl, respectively, with statistical significance (p < 0.01). U-MG/Cr (micrograms/mg. Cr) values were also different between them, being 9.28 +/- 4.97 in non-diabetics and 5.19 +/- 1.29 in diabetics, but with lesser statistical significance (p < 0.05) than S-Cr. U-MG/Cr correlated well with the terms till the initiation of dialysis therapy (r = 0.7189, p < 0.001), more significantly than S-Cr (r = 0.5506, p < 0.001) in parabolic regression analysis. U-MG/Cr were greatly varied among the 7 patients, although whose S-Cr was nearly the same level (6.0-6.9mg/dl). Most importantly, the tendency was found in these patients that the higher U-MG/Cr, the earlier the renal replacement therapy instituted. These results suggests that U-MG/Cr can be reliable parameter to predict the progression rate of renal failure and to help to know when renal replacement therapy should be instituted.