ABSTRACT
Background : hypercalciuria is defined as normocalcemia and increased urinary calcium excretion without any cause. Many studies have demonstrated that urinary calcium excretion is increased and glomerular hematuria is related to hypercalciuria in diabetic patients with severe proteinuria. This study was undertaken to elucidate whether patients with NIDDM are hypercalciuric and whether there is a pathophysiologic relationship between urinary calcium excretion, hematuria and the degree of diabetic nephropathy. The purpose of this study was to evaluate the incidence of hypercalciuria in NIDDM patients and the possible relationship among urinary calcium excretion, hematuria and proteinuria in diabetic nephropathy. Methods : We studied with 18 control subjects and 101 NIDDM patients without urinary infection. NIDDM patients with normal renal function (s- Cr<133micromol/L) followed at Kangbuk Samsung Hospital were included in this study from June, 1993 through March, 1995. Control group included 18 normal subjects and 101 NIDDM patients were divided into 3 groups : normoalbuminuria group, microalbuminuria group and macroalbuminuria group. Urinary albumin excretion rate (microalbumin) and urinary calcium and creatinine excretion ratio were measured. Kruskal-Wallis 1-way ANOVA test and multifactorial regression test were used to analyze. Results : 1) Age, duration of DM and serum creatinine level in macroalbuminuria group were significantly higher than normoalbuminuria group. 2) Calcium-creatinine ratio was significantly higher in NIDDM patients than in control subjects. Among diabetics it is significantly higher in microalbuminuria and macroalbuminuria groups than normoalbuminuria group. The incidence of hypercalciuria is 44.6% in patients with NIDDM. 3) Albumin excretion rate is correlated positively with calcium-creatinine ratio(r=0.26, p=0.0006), while no correlation was observed with serum creatinine, serum calcium, fasting blood glucose, postprandial 2hrs blood glucose, HbA1C, creatinine clearance, and body mass index. 4) Hematuria was observed in 3 cases with hypercalciuria(6.7%) and 4 cases without hypercalciuria(7.1%). No significant difference was observed between two groups. Conclusion : Hypercalciuria was more frequent in patients with NIDDM than in control. The severity of calciuria was correlated with the progression of diabetic nephropathy. There was no definite correlation between urinary calcium excretion and hematuria.