Urinary albumin excretion rate and glomerular filtration rate in single-kidney type 2 diabetic patients

Abstract

OBJECTIVE: To evaluate the urinary albumin excretion rate and the glomerular filtration rate of single-kidney type 2 diabetic patients and of single-kidney nondiabetic patients. PATIENTS AND METHODS: Patients who had only one kidney for at least 5 years, with no renal disease or hypertension at the time of the nephrectomy and with no calculus or systemic disease at the time of the evaluation, were included in this controlled cross-sectional study. A total of 20 single-kidney type 2 diabetic patients (eight men, age 62 ± 9 years; diabetes duration 8.5 ± 7 years), 17 single-kidney nondiabetic patients (two men, age 57 ± 13 years), and 184 type 2 diabetic patients who were matched to the single-kidney diabetic group for age, sex and body mass index were studied. Urinary albumin excretion rate was measured by immunoturbidimetry in timed 24-h sterile urine, and glomerular filtration rate was determined by the 51CrEDTA single-injection method. RESULTS: Single-kidney type 2 diabetic patients presented a higher proportion (eight of 20; 40%) of microalbuminuria (urinary albumin excretion rate 20-200 mg/min) than single-kidney nondiabetic patients (three of 17; 17.6%) and type 2 diabetic patients (37 of 184; 20%). Single-kidney diabetic patients presented a higher proportion of macroalbuminuria (urinary albumin excretion rate >200 mg/min; six of 20; 30%) than single-kidney nondiabetic patients (one of 17; 6%) but were similar to type 2 diabetic patients (43 of 184; 23%). The glomerular filtration rates of normaoalbuminuric singlekidney nondiabetic patients (71.7 ± 21.4 ml × min-1 × 1.73 m-2 ) and single-kidney type 2 diabetic patients (73.0 ± 21.5 ml × min-1 × 1.73 m-2 ) were similar but higher than the one-kidney glomerular filtration rate (GFR¸ 2) of the age-, sex-, and body mass index-matched normoalbuminiric type 2 diabetic patients (54.0 ± 11.6ml × min-1 × 1.73m-2). CONCLUSIONS: Increased GFR related to single-kidney status confers an increased risk of developing renal disease in the presence of diabetes.